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  • 1995-1999
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  • 1995-1999
  • 1985-1989  (1.388)
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  • 1
    Digitale Medien
    Digitale Medien
    Prenatal development of the cat thyroid: immunohistochemical demonstration of calcitonin in the “C” cells (1987)
    Springer
    Anatomy and embryology 177 (1987), S. 51-54 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Development ; Thyroid “C” cell ; Cat ; Immunohistochemistry ; Calcitonin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The presence of calcitonin in the cat thyroid was studied immunohistochemically in a series of gland development. the first positive cells are to be found on the 38th day of gestation, i.e. 1–2 days after level nine of ontogenetic development has been reached. The cytoplasm of these cells form only a narrow border round the nucleus. With advancing development the bumber of calcitonin-positive and its amount increases. From approximately the 50th day of prenatal development, the initially diffusely scattered, solitary calcitonin-positive cells are gradually replaced by groups of cells, which begin to occupy a characteristic position in relation to the follicular epithelium. The largest quantity of calcitonin-positive cells is found in foetuses about to be born. In non-pregnant adult cats, the incidence of immunohistochemically calcitonin-reactive cell is more sporadic and their distribution in the lobes of the thyroid is uneven.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00325289
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  • 2
    Digitale Medien
    Digitale Medien
    An investigation of pulp capillaries and tight junctions between odontoblasts in cats (1987)
    Springer
    Anatomy and embryology 177 (1987), S. 131-138 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Capillaries ; Tooth pulp ; Tight junctions ; Odontoblasts ; Ultrastructure ; Mineralisation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The relative roles of capillaries and odontoblasts in the process of dentinogenesis and in pulp reactions to trauma and pathology are not clear. Contributing to the problem is the paucity of information on odontoblast —capillary relationships and tight junctions between odontoblasts. Using light microscopy the capillaries have now been examined in semithin transverse sections of perfusion fixed teeth at different positions in the long axis from the apical foramina to the pulp horns. Odontoblastic capillaries were prominent in the coronal and middle regions of canines and present at the same levels of incisors. In the pulp horns and just coronal to the pulp horns capillaries were all subodontoblastic but near the apex there were also a few odontoblastic capillary profiles. Transmission electron microscopy on ultrathin sections revealed that a high proportion of middle and coronal odontoblastic capillary profiles were fenestrated but subodontoblastic profiles coronal to the pulp horns were the most fenestrated. In a search for tight junctions in ultrathin sections some typical strands were observed between odontoblasts. The difficult of obtaining the latter evidence was explained by the cellular arrangement of the odontoblasts which differed markedly from an ideal parallel, apically coplanar arrangement. The results question the possibility that there is a direct exchange of materials between pulp capillaries and dentine in teeth of limited growth and provide a baseline for future experiments to test the permeability of the odontoblast layer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00572537
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  • 3
    Digitale Medien
    Digitale Medien
    Structural alterations in the spinal cord during progressive communicating syringomyelia. An experimental study in the cat (1987)
    Springer
    Acta neuropathologica 72 (1987), S. 248-255 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Experimental communicating syringomyelia ; Ependyma ; Spinal cord ; Cat ; Scanning electron microscope
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A hydrocephalic-hydromyelic condition was induced in adult cats by causing the closure of the lateral apertures with intracisternal injections of kaolin. After displaying the symptoms characteristic of increased intracranial pressure, which lasted about 10–14 days but varied somewhat in intensity from animal to animal, the cats recovered. From approximately the 2nd post-operative week onward, a distended central canal was revealed by ventriculography; subsequently cavities developed in the tissue of the cord that communicated with the canal. Most cavities were located dorsal to the canal. The surfaces of the distended canal and the cavities showed that in ventral areas the ependyma streched but remained intact, whereas in dorsal areas it ruptured, exposing the nerve fibers to the cerebrospinal fluid (CSF). In cats which had been hydrocephalic for up to 2 years the walls of the cavities were covered by gliotic scar tissue; the nerve fibers were no longer exposed directly to the CSF.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00691097
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  • 4
    Digitale Medien
    Digitale Medien
    Vestibular and optokinetic eye movements evoked in the cat by rotation about a tilted axis (1987)
    Springer
    Experimental brain research 66 (1987), S. 522-532 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Off-vertical-axis rotation ; Eye movements ; Vestibulo-ocular reflex ; Optokinetic nystagmus ; Otoliths ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Horizontal and vertical eye movements were recorded from cats in response to either a) off-vertical axis rotation (OVAR) at a range of velocities (5–72 deg/s) and a range of tilts (0–60 deg) or b) horizontal (with respect to the cat) optokinetic stimulation (10–80 deg/s), also around a range of tilted axes (0–60 deg). The responses to stopping either of these stimuli were also measured: post-rotatory nystagmus (PRN) following actual rotation, and optokinetic after nystagmus (OKAN) following optokinetic stimulation. The response found during OVAR was a nystagmus with a bias slow-phase velocity that was sinusoidally modulated. The bias was dependent on the tilt and reached 50% of its maximum velocity (maximum was 73±23% of the table velocity) at a tilt of 16 deg. The phase of modulation in horizontal eye velocity bore no consistent relation to the angular rotation. The amplitude of this modulation was roughly correlated with the bias with a slope of 0.13 (deg/s) modulation/(deg/s) bias velocity. There was also a low-velocity vertical bias with the slow-phases upwardly directed. The vertical bias was also modulated and the amplitude depended on the bias velocity (0.27 (deg/s) modulation/ (deg/s) bias velocity). When separated from the canal dependent response, the build up of the OVAR response had a time constant of 5.0±0.8 s. Following OVAR there was no decline in the time constant of PRN which remained at the value measured during earth-vertical axis rotation (EVAR) (6.3±2 s). The peak amplitude of PRN was reduced, dependent on the tilt, reaching only 20% of its EVAR value for a tilt of 20 deg. When a measurable PRN was found, it was accompanied by a slowly-emerging vertical component (time constant 5.4±2s) the effect of which was to vector the PRN accurately onto the earth horizontal. OKN measured about a tilted axis showed no differences in magnitude or direction from EVAR OKN even for tilts as large as 60 deg. OKAN following optokinetic stimulation around a tilted axis appeared normal in the horizontal plane (with respect to the animal) but was accompanied by a slowly emerging (time constant 4.1±2 s) vertical component, the effect of which was to vector the overall OKAN response onto the earth horizontal for tilts less than 20 deg. These results are compared with data from monkey and man and discussed in terms of the involvement of the velocity storage mechanism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00270685
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  • 5
    Digitale Medien
    Digitale Medien
    Expression of “retinal” contrast gain control by neurons of the cat's lateral geniculate nucleus (1987)
    Springer
    Experimental brain research 66 (1987), S. 589-596 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Contrast gain control ; Lateral geniculate nucleus ; Temporal frequency ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This paper describes the temporal tuning of cells in the lateral geniculate nucleus of the cat (27 X cells, 51 Y cells) and how this changes with stimulus contrast. Drifting sinusoidal gratings of optimal spatial frequency were presented at 7 temporal frequencies (0.5, 1, 2, 4, 8,16 and 32 Hz) and 4 contrasts (10, 20, 40, 80%). For some cells response growth at all temporal frequencies was proportional to changes in contrast. Thus, their temporal tuning functions, on log-log axes, were displaced vertically with increasing contrast. This shift also largely characterizes the response to low temporal frequencies of the other neurons studied. For these other cells, however, responses to high temporal frequencies grew disproportionately large with increasing contrast generally causing their tuning functions to change shape. Typically the peaks of these functions shifted to higher frequencies at higher contrasts. Most of the X cells studied displayed behavior of the first type, while Y cells usually followed the second pattern. This qualitative impression was confirmed quantitatively. Cubic spline functions were fit to the temporal tuning functions obtained at different contrast levels and the peaks of the curves were extracted. X and Y cells preferred similar temporal frequencies at low contrast levels (X mean=8.1 Hz; Y mean=8.4 Hz) but Y cell values were significantly higher at higher contrasts (80%) (X mean= 12.0 Hz; Y mean=16.8 Hz). These contrast-dependent changes in the temporal characteristics of geniculate cells resemble those described for retinal ganglion cells by Shapley and Victor (1978 and subsequent). Thus, the gain control behavior of geniculate cells probably reflects the temporal properties of their retinal inputs with relatively little modification.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00270692
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  • 6
    Digitale Medien
    Digitale Medien
    Reduced binocularity in the noradrenaline-infused striate cortex of acutely anesthetized and paralyzed, otherwise normal cats (1987)
    Springer
    Experimental brain research 68 (1987), S. 593-605 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Ocular dominance ; Plasticity ; Noradrenaline ; Cat ; Visual cortex ; Squint effect
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In anesthetized and paralyzed cats, the normal alignment of the visual axes is disturbed by paralysis of the eye muscles. Thus, the separation between paired receptive fields of binocular cells in visual cortex is increased (paralysis squint). This increased separation is normally tolerated by the majority of visuocortical cells, about 80% of them being binocularly driven (Hubel and Wiesel 1962). It was shown previously that neuronal plasticity in visual cortex can be enhanced in both normal adult cats (Kasamatsu et al. 1979) and kittens (Kuppermann and Kasamatsu 1984) by intracortical microinfusion of noradrenaline (NA). In the present study we tested whether the usual range of disparity produced by the paralysis squint is sufficient to induce ocular dominance changes in visual cortex of adult cats when the neuronal plasticity is enhanced by NA. NA was continuously infused into visual cortex throughout the experiments. The period of the paralysis squint varied from experiment to experiment between 9 and 47 h. We found: (1) These short periods were sufficient to produce a marked reduction in the proportion of binocular cells. (2) The proportion decreased linearly with increasing the duration of the squint period at a rate of 0.17 per 10 h up to about 22 h. (3) At longer durations the average binocularity remained at about 0.30 and could not be further reduced in the present paradigm. (4) The binocularity seemed to decrease with increasing separation of paired receptive fields. (5) Binocularity increased again toward the normal value after optical correction of the squint. (6) The amount of increased binocularity was linearly correlated with the duration of the period after the squint correction. (7) The binocularity increased at a rate of 0.18 per 10 h, reaching the normal value in less than 30 h. We thus concluded that if visuocortical plasticity is maintained at a high level through the continuous infusion of NA it is possible to change the ocular dominance distribution in the mature visual cortex by manipulations of the alignment of the visual axes even in the acutely anesthetized and paralyzed condition.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00249802
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  • 7
    Digitale Medien
    Digitale Medien
    Receptive field properties of cells in area 19 of the cat (1987)
    Springer
    Experimental brain research 65 (1987), S. 549-558 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Area 19 ; Sinusoidal grating ; End-zone inhibition ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We have recorded extracellularly from single cells in area 19 of the cat for the purpose of providing a quantitative description of response characteristics. A prominent feature of this area is a high incidence of cells that are end-stopped. Drifting sinusoidal gratings were used to determine spatial and temporal characteristics of the discharge region. In addition, we have conducted independent tests to characterize end zones of receptive fields. When a grating patch was used to stimulate the discharge region alone, all of the cells showed a band-pass spatial frequency tuning characteristic. The optimal spatial frequency ranged from 0.1 to 1.13 cycles/deg, and the distribution had a peak at 0.4 cycles/deg. The bandwidth at half peak amplitude ranged widely from 0.7 to 3.3 octaves (mean 2.0 octaves). When gratings were also presented to the end zones, responses to stimulation of the central region were suppressed. The surround was phase-insensitive in that the relative phase between the grating in the two regions generally did not affect the strength of the suppression. To determine spatial characteristics of the end-zone inhibition, the spatial frequency of the end-zone grating was changed while that for the central pattern was fixed. All cells showed a bandpass characteristic for end-zone inhibition, but in each case, the tuning width was broader than that for excitation. The mean spatial frequency bandwidth of end-zone inhibition was 2.7 octaves. The peak of the inhibition generally coincided with the peak of the excitatory spatial frequency tuning of the discharge center. Considered together, these results show that neurons in area 19 share common properties with those in areas 17 and 18, but they exhibit phase-insensitve end-zone inhibition more frequently.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235978
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  • 8
    Digitale Medien
    Digitale Medien
    Automatic postural responses in the cat: responses of proximal and distal hindlimb muscles to drop of support from a single hind- or forelimb (1987)
    Springer
    Experimental brain research 65 (1987), S. 527-537 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Postural reflexes ; Unexpected postural perturbations ; Electromyographic activity ; Hindlimb muscles ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Cats respond to drop of the support from beneath a single limb with the “diagonal stance response” (Coulmance et al. 1979). They load the limbs on the diagonal opposite to the one containing the dropped limb and unload the third supporting limb in the diagonal containing the dropped limb. Characteristic biomechanical delays in limb motion and in vertical force changes imposed upon the limbs are observed. These delays range from 30 to 45 ms, depending upon the location of the dropped limb. This study describes the kinematics of the “diagonal stance response” and the activation of selected agonist-antagonist muscle pairs acting on the joints of the hindlimb during the response. Proximal and distal hindlimb muscles respond to perturbations in groups that are appropriate to the vertical forces imposed upon the limb. When the hindlimb containing the recording electrodes is loaded by drop of the contralateral hindlimb or the ipsilateral forelimb medium latency (25–45 ms) EMG responses occur in the extensors. This response serves to stiffen the limb against the increased vertical force of loading. A similar response is observed when the hindlimb is reloaded after being dropped. In this case, however, short latency responses precede the medium latency responses in muscles that are passively stretched by the limb drop. When drop of the diagonal forelimb unloads the hindlimb containing the electrodes, medium latency responses are observed in the distal hindlimb flexors, which indicates that the unloading is evoked in part by active lifting of the limb. In most cases, the medium latency responses precede or are coincident with the changes in force imposed on the limb, suggesting that the observed responses are centrally programmed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235976
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  • 9
    Digitale Medien
    Digitale Medien
    Neuronal dynamics in the visual corticothalamic pathway revealed through binocular rivalry (1987)
    Springer
    Experimental brain research 66 (1987), S. 10-20 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Corticothalamic feedback ; Binocular rivalry ; Lateral geniculate ; Vision ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Single unit activity was recorded from principal cells in the A-laminae of the cat dorsal lateral geniculate nucleus (dLGN). A steady state pattern of afferent activation was induced by presenting a continuously drifting square wave grating of constant spatial frequency to the eye (the dominant eye) that provided the excitatory input to the recorded cell. Intermittently, a second grating stimulus was presented to the other, nondominant, eye. In most neurones nondominant eye stimulation led to inhibition of relay cell responses. The latency of this suppressive effect was unusually long (up to 1 s) and its intensity and duration depended critically on the similarity between the gratings that were presented to the two eyes. Typically suppression was strongest when the gratings differed in orientation, direction of movement and contrast and when the nondominant eye stimulus was moving rather than stationary. Ablation of visual cortex abolished these long latency and feature-dependent interferences. We conclude that the visual cortex and the corticothalamic projections are involved in the mediation of these interocular interactions. We interpret our results as support for the hypothesis that corticothalamic feedback modifies thalamic transmission as a function of the congruency between ongoing cortical activation patterns and afferent retinal signals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00236196
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  • 10
    Digitale Medien
    Digitale Medien
    Responses of bradykinin sensitive tooth-pulp driven neurons in cat cerebral cortex (1987)
    Springer
    Experimental brain research 66 (1987), S. 435-439 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Bradykinin ; Tooth-pulp ; Cortical neuron ; Coronal gyrus ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The properties of single cortical neurons responding to electrical stimulation of the tooth-pulp and to intrapulpal application of bradykinin were studied in the cat. The activities of tooth-pulp driven neurons (TPNs) were recorded from the middle and anterior parts of the coronal gyrus of the cerebral cortex. Bradykinin-sensitive tooth-pulp driven neurons (BK-TPNs) were located in layer IV of area 3b of the anterior part of the coronal gyrus. These neurons had a large cutaneous oro-facial receptive field and received a nociceptive input from the facial skin as well as from the tooth-pulp. The BK-TPNs had a higher threshold and longer latency to electrical stimulation than TPNs insensitive to bradykinin (non BK-TPNs). These findings suggest that BK-TPNs in this cortical area may be involved in sensory processing of noxious information from trigeminal regions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00243318
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  • 11
    Digitale Medien
    Digitale Medien
    Responses of cat preoptic neurons to stimulation of the medial frontal cortex and the medial basal hypothalamus (1987)
    Springer
    Experimental brain research 66 (1987), S. 555-564 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Preoptic region ; Frontal cortex ; Medial basal hypothalamus ; Electrophysiology ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Responses of single preoptic neurons to electrical stimulation of the medial frontal cortex, the mediobasal hypothalamus (MBH) and the medial forebrain bundle (MFB) were recorded in anaesthetised cats. Single pulse stimulation of the medial frontal cortex orthodromically drove 96 otherwise quiescent preoptic neurons, which were found more frequently in the dorsal preoptic region, inhibited 53% of the spontaneously active preoptic neurons and excited 16%. Testing of cortically influenced preoptic neurons with MBH or MFB stimulation resulted in antidromic invasion of 6% (MBH) and 9% (MFB). Convergence of orthodromic inputs from medial frontal cortex and MBH was detected in 78% of spontaneously active preoptic neurons, and three-way convergence including input from MFB was noted in 17% of neurons tested with all stimulators. Some cortex-responsive neurons were found to also respond to vaginal or anal probing, paw squeezing and haemorrhage. The role of this input to the preoptic region from medial frontal cortex remains to be elucidated, but may include neuroendocrine, behavioural and homeostatic functions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00270688
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  • 12
    Digitale Medien
    Digitale Medien
    Branching cortical neurons in cat which project to the colliculi and to the pons: a retrograde fluorescent double-labeling study (1987)
    Springer
    Experimental brain research 67 (1987), S. 1-15 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Corticopontine collaterals ; Corticotectal neurons ; Cortex ; Cat ; Fluorescent tracers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The fluorescent double-labeling technique has been used to determine whether the corticopontine and the corticotectal fibers in the cat are derived from two different sets of neurons or whether they are derived from branching neurons which distribute collaterals to the pontine grey and the colliculi. After unilateral DY.2HCl injections in the pontine grey and FB injections in the ipsilateral colliculi, large numbers of FB-DY.2HCl double-labeled neurons were present in the cortex of the ipsilateral hemisphere. However, the labeled neurons in its rostral part may have represented pyramidal tract neurons which were labeled retrogradely because their fibers descended through the DY.2HCl injection area. Therefore, also DY.2HCl injections were made in the pyramid (i.e. caudal to the pons) and the cortical pyramidal tract area, containing the retrograde DY.2HCl-labeled neurons, was delineated. In the rest of the experiments only the DY.2HCl-labeled neurons in the caudal two thirds of the hemisphere (outside the pyramidal tract area) were taken into account because only these neurons could, with confidence, be regarded as corticopontine neurons. In some anterograde HRP transport experiments the trajectories of the corticotectal and the corticopontine fibers were visualized. On the basis of the findings the DY.2HCl injections in the pontine grey were placed such that they could not involve any of the corticotectal fibers passing from the cerebral peduncle to the colliculi. Thus artifactual doublelabeling of cortical neurons was avoided. However, also under these circumstances many double-labeled neurons were present in the caudal two thirds of the hemisphere. This led to the conclusion that in the cat a large proportion of the corticopontine neurons in the caudal two thirds of the hemisphere represent branching neurons which also distribute collaterals to the colliculi. The parietal (anterior part of the lateral gyrus, middle and posterior suprasylvian gyri) and the cingulate areas together contained three quarters of all labeled corticopontine neurons outside the pyramidal tract area. In the parietal areas roughly 25% of them were double-labeled and in the cingulate area 14%. However, in the visual areas 18 and 19 a much larger percentage (30–60%) was doublelabeled. In a recent study from our laboratory it was found that in the cat the pyramidal tract fibers distribute an abundance of collaterals to the pontine grey. Therefore, a large proportion of all corticopontine connections in this species appear to be established by branching neurons which also distribute fibers to other cell groups in the brain stem and the spinal cord.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00269447
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  • 13
    Digitale Medien
    Digitale Medien
    Detection latencies of X and Y type cells of the cat's dorsal lateral geniculate nucleus (1987)
    Springer
    Experimental brain research 65 (1987), S. 703-706 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cat ; Electrophysiology ; Lateral geniculate cells ; Signal detection ; Visual latencies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The latencies of visually-evoked responses from X- and Y-type neurons of the cat's dorsal lateral geniculate nucleus were measured in a manner that takes account of the inherent variability of discharge in these cells. Latencies measured in this way vary from trial to trial in one cell (and also between cells) by tens to as much as hundreds of milliseconds. This variability in the time for generation of reliable responses suggests that the much emphasized conduction advantage of the Y pathway plays a minor role in the detection of visual stimuli by the cat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235998
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  • 14
    Digitale Medien
    Digitale Medien
    Convergent inputs from articular, cutaneous and muscle receptors onto ascending tract cells in the cat spinal cord (1987)
    Springer
    Experimental brain research 66 (1987), S. 479-488 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Joint ; Spinal cord ; Pain ; Ascending tracts ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1.Responses were recorded from 160 ascending tract cells in segments L4 to L6 of the spinal cord in chloralose anaesthetized, spinalized cats. The tract cells were identified by antidromic activation following stimulation of pathways in the lateral and ventral funiculi at the level of the spinal cord transection at the thoracolumbar junction. Axonal conduction velocities ranged from 9 to 114 m/s. 2. A sample of 152 of the neurones examined could be subdivided according to the distribution of their receptive fields into 49 cells activated just from receptors located in skin (“s” cells), 17 neurones excited by receptors in deep tissues (“d” cells), 15 units with a convergent input from receptors in skin and deep tissues (“sd” cells), and 25 neurones with a convergent input from the knee joint and either skin (“sj” cells), deep tissues (“dj” cells) or both (“sdj” cells). No receptive fields could be demonstrated for the remaining 46 neurones. 3. “S” and “sj” cells were found almost exclusively in the dorsal horn, whereas many “d”, “sd”, “sdj” and “dj” units were in the ventral horn. Almost all of the cells that lacked receptive fields were in the ventral horn or intermediate grey. 4. Ninety-one of 158 cells (56%) demonstrated no background activity. Of these, 43 cells (27%) lacked receptive fields. Many of the silent neurones were in the ventral horn, but some were in the dorsal horn. Of 25 cells having knee joint input, 18 (72%) had background activity. 5. All of the neurones that had a receptive field in the knee joint also had a convergent input from receptors in other tissues. In 3 cases, there was a receptive field in the skin over the foot (“sj” cells). For 16 cells, receptive fields included not only the knee joint but also skin and deep tissue (“sdj” cells). Usually, the cutaneous receptive field was near the knee joint, but sometimes it was remote, such as on the foot. The deep receptive fields were chiefly in the muscles of the thigh and/or leg. For 6 “dj” cells, the receptive fields included not only the knee joint but also deep fields like those of “sdj” cells. 6. Cutaneous receptive fields were classified as “low threshold” (cells excited best by innocuous intensities of mechanical stimulation), “wide dynamic range” (cells activated by weak mechanical stimuli, but the best responses were to noxious stimuli) or high threshold (innocuous stimuli had little effect, but noxious mechanical stimuli produced a vigorous discharge). Similarly, stimulation of the knee joint with weak mechanical stimuli could excite some neurones, while others could be activated by weak or strong articular stimuli but were excited best by noxious stimuli, and still other neurones were activated by knee joint stimuli only if the intensity was noxious. 7. In several instances, contralateral receptive fields were noted. These were generally in deep tissue or in the knee joint. 8. It was concluded that many of the responses to articular stimulation of the spinal cord ascending tract cells examined in this study could have been mediated by the fine afferent fibres that supply the knee joint. Although further work will be required to determine which particular ascending tracts transmit nociceptive information concerning the knee joint, it can be proposed that many of the responses demonstrated here were likely to play a role in either joint pain of in triggering responses associated with joint pain.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00270680
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  • 15
    Digitale Medien
    Digitale Medien
    Lateral excitation in the cat lateral geniculate nucleus (1987)
    Springer
    Experimental brain research 67 (1987), S. 291-298 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Lateral inhibition ; Lateral excitation ; Cat ; Dorsal lateral geniculate nucleus ; GABA ; Silent synapses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Visual responses were elicited by global phase reversal stimuli in cells of the cat dorsal lateral geniculate nucleus (dLGN) after small retinal lesions had been centered on each receptive field. After acute lesions of different sizes exclusively lateral inhibition was found. When GABAergic inhibition was blocked by continuous microiontophoretic application of bicuculline lateral excitation emerged in dLGN cells partially deafferented by small and medium size acute retinal lesions, but not in those affected by large lesions. This indicates the presence of excitatory retinal inputs at the periphery of the dLGN cell dendrites which are normally suppressed by strong, long-ranging lateral inhibitory processes. After chronic deafferentation, the remaining excitatory inputs increase in effectiveness and lateral excitation is seen without blockade of inhibition. The maximal lateral spread of excitation (300 μm) in the dLGN is distinctly smaller than the extent of lateral inhibition (1000 μm).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00248550
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  • 16
    Digitale Medien
    Digitale Medien
    Automatic postural responses in the cat: responses of distal hindlimb muscles to paired vertical perturbations of stance (1987)
    Springer
    Experimental brain research 68 (1987), S. 477-490 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Postural reflexes ; Unexpected postural perturbations ; Electromyographic activity ; Motor control ; Hindlimb muscles ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The active components of the quadrupedal diagonal stance response to rapid removal of the support from beneath a single limb were studied in cats to further define the mechanisms that trigger and generate the response. We recorded EMG activity from lateral gastrocnemius and tibialis anterior muscles in awake, behaving cats while they stood on an hydraulic posture platform. By dropping the support from beneath a single limb, we evoked the diagonal stance response, with its characteristic changes in vertical force and EMG patterns. As the animal responded to this drop, a second perturbation of posture was then presented at intervals of 10 to 100 ms following the first. This second perturbation, which consisted of dropping the support from beneath the two limbs that were loaded as a result of the initial limb drop, made the first response biomechanically inappropriate. The EMG responses observed in both muscles during paired perturbations were triggered by the somatosensory events related to the perturbations. Muscle responses that were appropriate for the first perturbation always occurred with amplitudes and latencies similar to control trials. This was true even when the second perturbation occurred 10–20 ms after the first, that is, when this perturbation either preceded or was coincident with the response to the initial limb drop. The EMG responses that were normally associated with the second perturbation were delayed and/or reduced in amplitude when the time interval between perturbations was short. As the inter-perturbation interval was lengthened beyond 60–100 ms, however, EMG responses to the second perturbation were unaffected by the occurrence of the first perturbation. When the hindlimb containing the recording electrodes was dropped as part of the second perturbation, a myotatic latency response was observed in tibialis anterior. The amplitude of this response to the second perturbation was greater than controls when this displacement was presented during the period between initiation of the first perturbation and execution of the response to it. When the second displacement was presented after execution of the first response began, the amplitude of the myotatic response was reduced below control levels. While the results do not preclude the possibility that these “automatic” postural responses are segmental or suprasegmental reflexes, they support the hypothesis that the active component of the response to drop of the support beneath a single limb is centrally programmed and that the appropriate response can be riggered very rapidly by the somatosensory information signalling the perturbation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00249792
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  • 17
    Digitale Medien
    Digitale Medien
    The pattern of ocular dominance columns in flat-mounts of the cat visual cortex (1987)
    Springer
    Experimental brain research 68 (1987), S. 661-666 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Visual cortex ; Ocular dominance columns ; Flat-mount ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Ocular dominance (OD) columns in the cat visual cortex were visualized with autoradiography after intravitreal injection of (3H)proline. Extending previous studies, a flat-mount technique was applied that enabled the analysis of the distribution of label throughout extensive regions of the visual cortex without requiring reconstructions from serial sections. OD-columns were confined to layer IV and consisted of isolated patches and short bands. The latter were parallel to each other and regularly spaced, the main trajectory being orthogonal to the 17/18 border. This pattern of the geniculo-cortical terminals was similar in the hemispheres ipsi- and contralateral to the injected eye. The mean periodicities of the OD-bands were virtually identical in the two hemispheres of the same animal: 850 μm and 830 μm in cat D1 and 770 μm and 800 μm in cat D2. However, the ipsilateral OD-columns appeared smaller, more heavily labeled and more sharply delineated than the contralateral columns.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00249809
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  • 18
    Digitale Medien
    Digitale Medien
    Enhancement of the responses of ascending tract cells in the cat spinal cord by acute inflammation of the knee joint (1987)
    Springer
    Experimental brain research 66 (1987), S. 489-499 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Joint ; Pain ; Inflammation ; Spinal cord ; Ascending tracts ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. Recordings were made from 16 ascending tract cells in the spinal cords of anaesthetized, spinalized cats before and after an acute arthritis was produced by injection of kaolin and carrageenan into the knee joint. 2. The responses tested routinely were to passive flexion of the knee, an innocuous movement. In some cases, responses to other movements were also tested, and changes in background discharge rates were monitored. 3. Control recordings for a period of 1 h or in 3 cases of 3 h indicated that the responses to flexion were reasonably stationary. 4. Four tract cells that initially showed little or no response to flexion of the knee joint developed large responses within 1 to 2 h after inflammation of the joint. 5. Another 9 cells were tested that had responses to flexion of the knee joint prior to inflammation. In 6 cases, inflammation produced enhanced static or transient responses. In 2 cases, the effect of flexion was initially inhibitory or variable, but after inflammation these cells showed large excitatory responses. In the other case, inflammation had no effect. Background discharges were increased by inflammation in 6 of these 9 cells. 6. The effect of inflammation of the knee joint was tested on 3 tract cells that had no clearly defined receptive field in the knee. In 1 case, a response developed to knee flexion after acute inflammation was produced. In the other 2 cases, there were initially responses to knee flexion, but these were unchanged by inflammation. 7. Two of the cells tested had bilateral receptive fields in or around the knee joints. Inflammation of one knee joint enhanced the responses to flexion of the same but not of the contralateral knee in one case but greatly increased the responses to flexion of both knees in the other case. 8. Injections of prostaglandin (PGE2) caused an enhancement of the responses to knee flexion beyond that caused by inflammation in 5 of 7 cases. One cell whose responses to flexion of the knee were unaffected by inflammation showed inhibitory responses to prostaglandin injections into the inflamed knee joint. 9. The effects of inflammation on the responses of ascending tract cells of the spinal cord appear to serve as a useful neural model of the events responsible for the development of arthritic pain.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00270681
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  • 19
    Digitale Medien
    Digitale Medien
    Synaptic organization of olfactory inputs and local circuits in the entorhinal cortex: a current source density analysis in the cat (1987)
    Springer
    Experimental brain research 67 (1987), S. 615-622 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Entorhinal area ; Current source density ; Olfactory afferents ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The distribution of the olfactory afferents within the ventrolateral part of the entorhinal cortex (EC) was studied by means of field potentials evoked by stimulation of the olfactory bulb (OB) and the olfactory cortex (PPC). Depth profiles of the field potentials evoked by OB or PPC stimulation were studied using current source density analysis. After OB or PPC stimulation an early superficial sink-deep source configuration was found, which some time later reversed into a superficial source-deep sink. Both OB and PPC activated mainly the superficial dendrites of the cells of layers II and III. In layers II and III evidence for strong recurrent inhibition was found, using double pulse stimulation. The results indicate that there exists a common basic design of the synaptic organization of the olfactory areas of the base of the brain extending to the EC.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00247292
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  • 20
    Digitale Medien
    Digitale Medien
    Direct projections from Ammon's horn to the septum in the cat (1987)
    Springer
    Experimental brain research 68 (1987), S. 179-188 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Ammon's horn ; Hippocampus ; Septum ; Dentate gyrus ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Direct projections from Ammon's horn to the septum were studied in the cat by the anterograde tracing method after injecting WGA-HRP (wheat germ agglutinin-horseradish peroxidase conjugate) into Ammon's horn. The results were further confirmed by the retrograde WGA-HRP method after injecting WGA-HRP into the septum. Pyramidal neurons in fields CA1, CA2 and CA3 were observed to send their axons ipsilaterally to the lateral septal nucleus; the septal parts of the hippocampus sent projection fibers to the dorsomedial portions of the lateral septal nucleus via the medial aspects of the subcallosal fornix, while the hippocampal regions successively more proximal to the temporal pole sent projection fibers to progressively more ventrolateral portions of the lateral septal nucleus via more lateral aspects of the subcallosal fornix. It was also found that the septal parts of fields CA1, CA2 and CA3 sent projection fibers bilaterally to the dorsomedial aspects of the lateral septal nucleus. Field CA4 appeared to send projection fibers only sparsely, if at all, to the medial septal nucleus. The rudimentary parts of the hippocampal formation, taenia tecta and indusium griseum, were found to have reciprocal ipsilateral connections with the dorsal portions of the lateral septal nucleus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00255243
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  • 21
    Digitale Medien
    Digitale Medien
    Binocular interaction in the dorsal lateral geniculate nucleus of the cat (1987)
    Springer
    Experimental brain research 68 (1987), S. 305-310 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Binocular interaction ; Lateral geniculate nucleus ; Cat ; Retinal disparity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We have investigated binocular interaction in the dorsal lateral geniculate nucleus (LGN) of the cat. Neurons were recorded extracellularly during visual stimulation with sinusoidal gratings which were presented at different interocular phases (disparities). The large majority of cells (91%) exhibited some type of binocular interaction. For 75% and 16% of the total number of cells, the binocular interaction was inhibitory or facilitatory, respectively. For the remaining 9% of cells, no interaction was evident. In marked distinction from visual cortex, the facilitatory and inhibitory interactions in the LGN are independent of the relative interocular phase of the patterns. Neurons in the LGN are therefore insensitive to the stereoscopic depth cue, retinal disparity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00248796
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  • 22
    Digitale Medien
    Digitale Medien
    Processing of interaural time and intensity differences in the cat inferior colliculus (1987)
    Springer
    Experimental brain research 68 (1987), S. 379-392 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cat ; Inferior colliculus ; Single cell recording ; Binaural hearing ; Time/intensity trading
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. Binaural neurones were recorded in the central nucleus of the cat inferior colliculus and were stimulated with tone and noise bursts. Closed field sound systems were used to produce independent interaural time (ITD) and intensity (IID) differences. Particular attention was paid to high frequency (above 2 kHz) cells. 2. Three main types of binaural neurone were found: High frequency excitatory-inhibitory neurones (EI cells), excited by input from the contralateral ear and inhibited by ipsilateral input, high frequency excitatory-excitatory cells (EE cells), excited by inputs from either ear and low frequency cells sensitive to interaural phase differences (IPD cells). 3. The EI cells had characteristics similar to those of IE cells in the contralateral lateral superior olive. They were sensitive to envelope ITDs (most cells) and IIDs (all cells) favouring the contralateral ear. The response of these cells increased with increasing contra lead ITDs or contra loud IIDs up to values well outside the physiological range. 4. Low frequency binaural cells were sensitive to interaural phase differences (IPDs). The peak response was often in the contralateral physiological range and the response was unaffected by IIDs. 5. Many high frequency EE cells were sensitive to envelope ITDs. These units were relatively unaffected by IID. Although the ITD sensitivity of these cells was generally less than that of the IPD cells, the peak response of the ITD curve was also often in the contralateral physiological range. 6. Some of the high frequency EI and EE cells were sensitive to ongoing time differences (OTDs) in white noise signals, i.e. they showed ITD response curves to carrier only shifted noise bursts. 7. The EI cells often showed recovery from inhibition at large ipsilateral lead. This tendency was increased as the sound pressure level on the inhibitory side was lowered and by the use of click stimuli. Similarly, cycles of suppression could be seen to follow excitation in some EE cells. The time course of these effects was in the order of hundreds of μs. 8. Binaural characteristics (degree of ITD, IID or OTD sensitivity) showed considerable interunit variation within each cell type. These variations were also affected by signal type (tone or noise bursts) and did not appear to be correlated with best frequency, nature of the tuning curve or PSTH type. We suggest that the time course of the inhibitory and excitatory effects at each unit (and its interaction with the signal type) determines the type of ITD response and that this time course varies from cell to cell.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00248803
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  • 23
    Digitale Medien
    Digitale Medien
    Effects of monocular strobe rearing on kitten striate cortex (1987)
    Springer
    Experimental brain research 68 (1987), S. 525-532 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cat ; Visual cortex ; Stroboscopic exposure ; Monocular experience ; Motion deprivation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Monocular deprivation in kittens does not lead to an ocular dominance shift in striate cortex if the visual stimuli do not contain contours. In the present study we sought to find out whether an ocular dominance shift is produced if the visual environment does contain contours but is devoid of motion. Six kittens were reared with one eye occluded in a visual environment that was lit only by the light of a stroboscope (2 flashes per sec). Exposure was started at 5–6 weeks of age after dark-rearing from birth and extended until 8–12 weeks of age for 8 h per day. The rest of the time was spent in total darkness. Thus, the animals were completely deprived of vision in one eye, while the other eye experienced only stationary flashing contours. Single units in area 17 of these animals were studied and compared to normally reared cats. In all six animals ocular dominance was clearly shifted towards the eye with strobe experience. The ocular dominance shift showed, however, the following interdependencies with other parameters: neurones that responded to stationary flashing test stimuli were nearly always dominated by the strobe eye; neurones that responded only to moving bars or edges remained binocular. In the normal control animals the ocular dominance distribution was similar for both groups of cells. Track analysis according to cortical lamination revealed that neurones in infragranular layers consistently showed a weaker OD shift towards the strobe eye than neurones in supragranular layers (including layer 4). Response latencies to stationary flashing stimuli were significantly shorter in the strobe-reared animals than in the normal controls. Orientation tuning was normal in all animals. Directional tuning was reduced after monocular strobe experience, but not by the same amount as described after binocular strobe rearing. The present results demonstrate that monocular visual experience reduced to stationary flashing contours is sufficient to produce on ocular dominance shift in striate cortex. This adds further support to existing notions about the role of nervous activity for changes in cortical connections. Cortical responses to afferent stimulation and the resulting correlated activation of pre- and postsynaptic neurones seem to be a prerequisite for a stabilization of synaptic connections.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00249796
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  • 24
    Digitale Medien
    Digitale Medien
    Tonotopic organization in the medial geniculate body (MGB) of lightly anesthetized cats (1987)
    Springer
    Experimental brain research 69 (1987), S. 24-42 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Medial geniculate body ; Tonotopic organization ; Single unit pairs ; Frequency selectivity ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In the medial geniculate body (MGB) of nitrous oxide anesthetized cats, the pars lateralis (PL) was the only nucleus to show a clear topographic arrangement of its neurons according to their characteristic frequency (CF). When compared to barbiturate anesthetized cats (Imig and Morel 1985a), the tonotopic organization in PL appeared less strict and was characterized by a significant local CF disparity. Furthermore, the degree of tonotopic organization varied along the rostrocaudal axis of the nucleus: it was lower in its caudal than in its rostral half. In the pars ovoidea, the rostral half of the pars magnocellularis (PM) and the suprageniculate nucleus, CF sequences and quantitative evaluations of the tonotopicity indicated the presence of some degree of tonotopic organization which was lower than in PL. No such organization was observed in the caudal part of PM nor in the ventrolateral nucleus, while in the dorsal nucleus, the proportion of toneresponding units was too low for a significant analysis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00247026
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  • 25
    Digitale Medien
    Digitale Medien
    The effects of CO2 and fixed acid on the O2-Hb affinity of rabbit and cat blood (1987)
    Springer
    Pflügers Archiv 408 (1987), S. 451-457 
    Details
    ISSN: 1432-2013
    Schlagwort(e): O2-Hb affinity ; Bohr effect interaction ; CO2 Bohr effect ; Fixed acid Bohr effect ; Rabbit ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The action of respiratory and metabolic acid-base disturbances on the O2-Hb affinity was studied in rabbits and cats. Blood samples of both species were exposed to in vitro pH-changes, which were either achieved by variation ofPCO2 (2.8–8.3 kPa) at constant lactic acid concentration, or by addition of lactic acid (5–14 mmol·l−1) at constantPCO2. ThePO2 at halfsaturation (P50) and the Hill'sn were determined from O2-Hb dissociation curves (ODC) in a range between 20 and 80% SO2. Under standard conditions (T=331 K,PCO2=5.33 kPa, pH=7.4), the average P50 value was 4.66±0.05 kPa in rabbits, that is slightly higher than reported by others, and 5.17±0.03 kPa in cats. The average values of Hill'sn were 2.91±0.02 and 2.95±0.03 for rabbits and cats, respectively. When plasma pH was varied by CO2, the resulting classical CO2 Bohr factor φCO2=ΔlgP50/ΔpH50 was distinctly higher in cats (−0.560±0.006,n=25) than in rabbits (−0.504±0.014,n=22), although in the latter species being even higher than reported elsewhere. Concomitant metabolic acidosis did not significantly affect φCO2, but shifted the P50 at a given plasma pH to lower values. Substitution of lactic acid with equimolar amounts of sodium lactate left both φCO2 and P50 unchanged. When plasma pH was varied by lactic acid (LA), the resulting fixed acid Bohr factors φLA were similar for cats (−0.420±0.016,n=21) and rabbits (−0.427±0.010,n=18), and not influenced by additional respiratory acidosis. Concomitant respiratory acidosis, however, shifted the P50 at a given plasma pH to higher values. The deviation of lgP50 from that under standard conditions (lgP50st) induced by both, respiratory and metabolic acid-base changes, can generally be expressed by Eqs. (1) or (2) (1) $$1gP_{50} - 1gP_{50} st = \varphi CO_2 \left( {pH - 7.4} \right) - \left( {\varphi CO_2 - \varphi LA} \right) \cdot \left[ {pH\left( {LA} \right) - 7.4} \right]$$ (2) $$1gP_{50} - 1gP_{50} st = \varphi LA\left( {pH - 7.4} \right) + \left( {\varphi CO_2 - \varphi LA} \right) \cdot \left[ {pH\left( {CO_2 } \right) - 7.4} \right].$$ Thereby, the first term considers the total pH-deviation, irrespective of its origin, and the second term represents the metabolic (1) or the respiratory (2) correction. For practical use and within the physiological range of plasma pH (7.2–7.6), φCO2 and φLA are assumed to be additively linked and to be independent of pH. Once these factors are determined for a given species, together with the buffer capacity for CO2, they provide sufficient data to estimate fairly accurately the position of the ODC. This is particularly important for in vivo conditions where respiratory and metabolic acid-base disturbances often occur simultaneously.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00585068
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  • 26
    Digitale Medien
    Digitale Medien
    Responses of sacral visceral afferents from the lower urinary tract, colon and anus to mechanical stimulation (1987)
    Springer
    Pflügers Archiv 410 (1987), S. 296-303 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Sacral visceral afferents ; Pelvic nerve ; Urinary bladder ; Urethra ; Colon ; Anus ; Functional properties ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The discharge characteristics of sacral visceral afferents supplying the urinary bladder, urethra, colon and anus to mechanical stimuli were analyzed in the anaesthetized cat. The stimuli used were passive distension (urinary bladder, colon), isovolumetric contraction (urinary bladder), movements of the urethral catheter and mechanical shearing stimuli (mucosal skin of the anal canal). (1) In total 245 afferent units which projected in the pelvic nerve were isolated from the sacral dorsal roots. From one of the following organs, urinary bladder, colon, urethra and anus 117 afferent units were activated. By these stimuli from the bladder, urethra and anus 122 afferent units could not be activated, and as far as tested also not from the colon; in 6 afferent units the classification was unclear. (2) Afferent units from the urinary bladder and the colon responded consistently to passive distension of the respective organ. The units from the urinary bladder showed graded responses at intraluminal pressures of about 10–70 mm Hg and responded also to isovolumetric contractions of the organ. The thresholds of the units from the bladder to passive distension and contraction varied from about 5 to 20 mm Hg intravesical pressure. (3) The afferent units from the urethra and the anus did not react or showed some weak phasic and irregular responses to distension and contraction applied to the urinary bladder or to distension of the colon. They were consistently excited by low threshold mechanical stimulation of the urethra and anus, respectively. (4) The axons from the bladder, urethra and anus were presumably myelinated (conduction velocity above 2 m/s) and conducted at 10.3±6.1 m/s (n=34, mean±SD), 26.3±9.3 m/s (n=13) and 9.5±5.1 m/s (n=37), respectively. The axons from the colon conducted at about 0.5 to 16 m/s (n=20), 13 of them conducting at less than 2 m/s. About 75% of the axons which could not be activated by mechanical stimulation of the visceral organs were presumably unmyelinated (conduction velocity below 2 m/s). (5) Some ongoing activity was found in 9 out of 26 afferent units from the anus but, with one exception, the afferent units from the bladder, urethra and colon were silent. (6) It is concluded that the pelvic afferent units from the urinary bladder, urethra, colon and anus consist of distinct populations with characteristic response patterns. There is no indication from this investigation that the urinary bladder is supplied by sacral afferents which are only recruited at high intravesical pressures during passive distension and isovolumetric contractions and which are possibly associated with pain.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00580280
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  • 27
    Digitale Medien
    Digitale Medien
    Contraction properties and motor nucleus morphology of the two heads of the cat flexor carpi ulnaris muscle (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 17-23 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Previous studies have examined the isometric contraction properties of the two heads of the cat flexor carpi ulnaris acting as a single unit. In this study, the contraction properties and fiber architecture of each head of the flexor carpi ulnaris were determined separately and related to previous reports on the histochemical characteristics of this muscle. The morphology of retrograde-labeled motor nuclei for the two heads of the muscle was also examined. The humeral head had a significantly longer contraction time (48 msec) than the ulnar head (36 msec) as well as a significantly lower tetanic fusion frequency (28 Hz vs. 35 Hz). The maximum tetanic tension per gram of muscle tissue was 71% greater in the ulnar head. Motoneurons of the flexor carpi ulnaris formed a column 12 mm long and 0.5 mm wide in the center of the ventral grey in spinal segments C8 and T1. The ulnar head had α-motoneurons with greater soma diameters than those in the humeral head. The smaller soma diameter, slower contraction time, and weaker contraction in the humeral head correlate with the preponderance of oxidative-metabolic muscle fiber types found in the humeral head by other workers. These correlations suggest that the humeral head plays a major role in maintaining a sustained antigravity tension that prevents the wrist from buckling during standing.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910103
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  • 28
    Digitale Medien
    Digitale Medien
    Ontogeny of the hyobranchial apparatus in the salamanders Ambystoma talpoideum (Ambystomatidae) and Notophthalmus viridescens (Salamandridae): The ecological morphology of two neotenic strategies (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 205-214 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Comparison of metamorphosis of skull and hyobranchial system in two species of neotenic salamanders reveals two different types of neoteny. Ambystoma talpoideum is completely neotenic owing to delayed metamorphosis. Notophthalmus viridescens exhibits limited neoteny as a result of incomplete metamorphosis. Morphological details of neoteny are compared to life history in both species in order to discuss the ecological morphology of the two neotenic strategies. Comparisons to Taricha granulosa, Triturus vulgaris, and Ambystoma gracile indicate that these two strategies are widely employed and may represent familial patterns.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910210
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  • 29
    Digitale Medien
    Digitale Medien
    Neuromast topography in urodele amphibians (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 247-263 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Using scanning electron microscopy I determined neuromast number and orientation, neuromast sensory epithelial surface area and relative position, hair cell number per neuromast, hair cell size, and stitch formation in aquatic urodeles. All aquatic salamanders examined (34 specimens, 20 species, 16 genera, nine families) had neuromasts. The basic pattern of neuromast organization was similar in all species, consisting of a single row of circumorbital (supraorbital + infraorbital) neuromasts and anteriorly along the snout two rows of nasal and three rows of maxillary neuromasts. Nasal and maxillary groups consisted of orthogonally oriented neuromasts. Variation in most parameters occured at every taxonomic level, between individuals of the same species, and even on opposite sides of the same individual. Among species, primary neuromast number ranged from 94 to 150, with plethodontids having higher numbers. Despite high intraspecific variation, neuromast number fell into a sufficiently narrow range to be useful systematically. Hair cell number per neuromast was greater in species with larger animals. Hair cell number per neuromast and number of primary neuromasts did not increase with growth. In some species primary neuromasts divided to form secondary neuromasts (together termed a stitch). Two types of stitches-transverse and longitudinal-were formed. Transverse stitches were characteristic of ambystomatids and cryptobranchids, longitudinal stitches were characteristic of proteids and salamandrids. Because transverse stitches are also characteristic of anurans, this trait may be the generalized condition in at least these two amphibian orders. With stitch formation total number of hair cells on the dorsal surface of the head of these animals can be increased over tenfold to almost 20,000. Ecologically, lentic forms tended to form transverse stitches, while lotic forms had single neuromasts in epidermal pits or longitudinal stitches in epidermal grooves. Lotic forms also tended to have more primary neuromasts and more nasal and maxillary neuromasts.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910306
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  • 30
    Digitale Medien
    Digitale Medien
    Ultrastructural investigations on the labral glands of Daphnia obtusa (Crustacea, Cladocera) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 23-33 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The labral glands of Daphnia consist of three distinct functional units on each side: (1) several cells at the base of the head, (2) two large cells at the base of the labrum and one large cell (cell A) in the median part of the labrum and (3) one large cell (cell B) in the median part of the labrum. These gland cells do not form a syncytium, contrary to reports by previous investigators. With the exception of cell B, they have a well-developed rough endoplasmic reticulum and many active Golgi complexes. The Golgi activity changes during the molt cycle. The Golgi activity of the cells of the head base is different from that of the large cells of the labrum. Since clear exocytotic phenomena were not observed, the secretion can be assumed to flow into the hemolymph after accumulation in the enlarged intercellular spaces. Cell B has a distinctive cytoplasmic ultrastructure the function of which is not yet understood.The four large cells of the labrum are in contact with a duct cell (or several duct cells) characterized by a deep infolding of the plasma membrane. This delimits a narrow lumen, which contains no secretion. No passage of substance is visible from the gland cells to the duct cell(s).
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930104
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  • 31
    Digitale Medien
    Digitale Medien
    Comparative study of the adrenergic innervation of the teleost gill (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 63-73 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The adrenergic innervation of structures in the gills of six teleost species was studied with catecholamine fluorescence histochemistry. The species studied were the following: sand flathead, Platycephalus bassensis and blue-spot flathead Platycephalus caeuruleopunctatus (Platycephalidae); smooth toadfish, Tetractenos glaber (Tetraodontidae); Australian short-finned eel, Anguilla australis (Anguillidae); river blackfish, Gadopsis marmoratus (Gadopsidae); and common carp Cyprinus carpio (Cyprinidae).In all species except C. carpio fluorescent components were observed in the branchial nerves in the gill arch.In the arterio-arterial vascular pathway, the afferent and efferent branchial arteries were innervated only in Cyprinus. Fluorescent nerve fibres were found on afferent filamental arteries of all species except A. australis and on many afferent lamellar arterioles of all species except T. glaber. The secondary lamellae were devoid of fluorescent nerve fibres in all species. In Cyprinus and Anguilla, fluorescent nerve fibres were observed on occasional efferent lamellar arterioles. In Cyprinus, there was an additional innervation on the basal one-third of the efferent filamental artery. The innervation of the arteriovenous vascular pathway was similar in all species. Fluorescent nerve fibres were found on nutritive arterioles, and in the core of each filament between the surface epithelium and the wall of the filament venous sinus.Since most of the adrenergic innervation was found on afferent vessels of the arterio-arterial pathway, it is suggested that adrenergic nerves and circulating catecholamines may have distinct functions in the regulation of blood flow through the gills.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930107
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  • 32
    Digitale Medien
    Digitale Medien
    Ovary of the pipefish, Syngnathus scovelli (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 117-133 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Gross dissection, light microscopy, and transmission electron microscopy were used to generate a detailed understanding of the ovarian anatomy of the pipefish, Syngnathus scovelli. The ovary is a cylindrical tube bounded by an outer layer consisting of a smooth muscle wall and an inner layer of luminal epithelium, with follicles sandwiched between the two layers. A remarkable feature of this ovary is a sequential pattern of follicle development. This pattern begins at the germinal ridge with a gradient of follicles of increasing developmental age extending to the mature edge. The germinal ridge is an outpocketed region of the luminal epithelium containing early germinal cells and somatic prefollicular cells. Therefore, the germinal ridge and luminal epithelium share the same ovarian compartment and follicle formation occurs within this compartment. The mature edge is defined as the site of oocyte maturation and ovulation. The outer ovarian wall contains unmyelinated nerve fibers throughout. Longitudinally oriented unmyelinated nerves are also observed near the smooth muscle bundles associated with the mature edge. Oocytes near the mature edge are polarized such that the germinal vesicle (nucleus) is generally oriented toward the luminal epithelium. The sandwichlike organization of the ovary results in follicles that have a shared theca. An extensive lymphatic network is also interspersed among the follicles. Thus, the exceptional features of the pipefish ovary make it particularly well suited for the examination of early events in oogenesis. Specifically, we characterize pipefish folliculogenesis in detail.
    Zusätzliches Material: 25 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930202
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  • 33
    Digitale Medien
    Digitale Medien
    Hemocytes of Leiobunum limbatum and two other species of harvestmen (Arachnida, Opiliones): Morphological classification and functional aspects (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 185-196 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The hemocytes of Leiobunum limbatum, Mitopus morio, and Opilio ravennae number from about 8,000 (juveniles) to 41,000 (pregnant females) per microliter of hemolymph. Five different types of hemocytes occur in all three species and both sexes. According to their ultrastructural appearance and their similarities to other arthropod hemocytes these five types are designated as prohemocyte, plasmatocyte, granulocyte, coagulocyte, and spherulocyte. From the ultrastructural point of view the prohemocytes are interpreted as stem cells for plasmatocytes which on their part differentiate into granulocytes. Transitional stages which would indicate the origin of coagulocytes and spherulocytes could not be found.Granulocytes and spherulocytes are interpreted as being storage cells; coagulocytes burst when hemolymph is transferred to a microscopic slide. Plasmatocytes are involved in the removal of dead cells or cell fragments. Plasmatocytes are demonstrated as being able to phagocytize and digest bacteria.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930206
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  • 34
    Digitale Medien
    Digitale Medien
    Seasonal changes in a lizard pituitary: Immunocytochemistry and ultrastructural morphometry of lactotropes, corticotropes, and gonadotropes (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 225-239 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Pituitary glands of adult male lizards (Anolis carolinensis) were studied in an effort to monitor seasonal cytologic changes quantitatively. Cells were identified immunocytochemically and on the basis of ultrastructural characteristics.Electron micrographs of the anterior pars distalis (containing lactotropes, corticotropes, and gonadotropes) of lizards collected in spring and fall were analyzed morphometrically. Lactotropes are the most numerous cell type in this area and occupy the largest volume. They are closely followed by corticotropes. Neither kind of cell undergoes a marked seasonal change in number or size or in the percent of the analyzed volume they occupy. Morphometric and ultrastructural criteria indicate an increased level of activity in all three kinds of secretory cells in the spring, although changes are relatively modest in corticotropes and lactotropes.Gonadotropes occupy less than half the volume of either of the other secretory cells in the analyzed area, but undergo considerable seasonal modification. They are larger (〉 40%) and more numerous (20%) in the spring, and show an increase in biosynthetic organelles at this time. Although the density of secretion granules may be reduced in the enlarged spring gonadotropes, the number of granules per cell may not be altered seasonally.Seasonal changes in the three cell types analyzed are moderate in contrast to the cytologic modifications described in pituitary cells following castration or other experimental procedures. Necrotic cells appear to be a normal component of the pituitary gland of Anolis carolinensis throughout the year.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930302
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  • 35
    Digitale Medien
    Digitale Medien
    Formation of the septate junction in regenerating planarian gastrodermis (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 205-215 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Septate junctions develop initially just basad from apical junctional complexes at the apical ends of regenerating gastrodermal cells. The first morphological indication of differentiation of the junction is the appearance of gentle undulations of the plasma membranes of apposing cells. Subsequently dense dots develop at fairly regular intervals at the cytoplasmic surface of one cell, while SER cisternae become localized opposite them near the surface of the apposing cell. The dense dots are associated with bulges which narrow the intercellular space. Later the dense dots are replaced by filaments aligned along the inner leaflet of the parent cell. Strands of amorphous deposits form connections between SER cisternae and the sister membrane on the opposite side of the junction. Ruthenium red staining provides information on precursors which occupy the intercellular space between the apposed plasma membranes. As development of the junction progresses, ruthenium red stains only the newly formed septa but not the interseptal matrix. Regular arrangement of individual septa seems to be completed under the control of V-projections from both of their surfaces. Precursors for the structural material of the septa may be a secretory product derived from the SER. Dense dots and their derived filaments probably serve as reinforcing material for strengthening the cell membrane of the junction.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920303
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  • 36
    Digitale Medien
    Digitale Medien
    Fine structure and histochemistry of the freshly extruded and hardened spermatophore of the spiny lobster, Panulirus interruptus (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 237-246 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Freshly extruded and hardened spermatophores of the spiny lobster, Panulirus interruptus, were compared using light and electron microscopy (EM). The spermatophore is composed of a sperm tube embedded in an acellular matrix. The sperm tube consists of tightly packed spherical cavities in an acellular material within which the sperm lie. The extruded spermatophore is white, soft, and sticky on all surfaces. The highly coiled sperm tube can be seen near the surface of the foot of the spermatophore, which is the side that will attach to the exoskeleton of the female. The opposite surface, the cap, will harden and darken after exposure to seawater. In the soft spermatophore, the matrix surrounding the sperm tube and extending from foot to cap is composed of small (2-μm) granules embedded in a loose weave of filaments. In the hardened spermatophore, the matrix is composed of small (4-μm) empty spheres. At the cap region the matrix darkens, and at the foot the granules dissolve to form a thick layer characterized by vertical striations. The structure of this spermatophore is compared to those spermatophores of other decapods that have been described at the EM level. The chemical composition and possible function(s) of the various components are discussed.
    Zusätzliches Material: 17 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920306
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  • 37
    Digitale Medien
    Digitale Medien
    Morphology of the nervous and muscular systems in the heads of pedicellariae from the sea urchin Echinus esculentus L (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 35-51 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Light and electron microscopy reveal that simple receptor cells in the jaw epithelium of sea urchin pedicellariae are connected by nerve tracts to the neuropile that coordinates jaw movements. The muscles responsible for jaw opening and closure and for flexion of the stem are all innervated in this neuropile. At least two types of vesicles occur at the simple synapses between neurone profiles and at neuromuscular junctions. The muscles include both striated and smooth fibres; however, their distribution varies according to pedicellaria type, and an unexpected arrangement exists in trifoliate pedicellariae.
    Zusätzliches Material: 25 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930105
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  • 38
    Digitale Medien
    Digitale Medien
    Morphology, sense organs, and regeneration of the forelegs (whips) of the whip spider Heterophrynus elaphus (Arachnida, Amblypygi) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 75-89 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In the whip spider Heterophrynus elaphus the first pair of legs is specialized to serve sensory functions. The morphology of these “whips” and the sensory organs of their tarsi and tibiae are described using scanning and transmission electron microscopy. The tarsus is normally subdivided into 74 segments and bears 7 types of sensory hairs: bristles, club sensilla, two types of porous sensilla, two types of rod sensilla, and leaflike hairs. In addition there are modified claws, 3 kinds of slit sense organs, a “pit organ,” a “plate organ,” and probably a joint receptor. The tibia is usually subdivided into 33 segments. In addition to bristles the tibia bears 7 trichobothria at constant locations and a lyriform slit sense organ. The functional and systematic implications of these findings are discussed.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930108
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  • 39
    Digitale Medien
    Digitale Medien
    Cytological and cytochemical investigations of development from dormant gemmules of the marine sponge, Haliclona loosanoffi (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 99-116 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Vernalized gemmules of the marine sponge Haliclona loosanoffi were cultured at 20°C, fixed at 24-hour intervals (0-11 days), and processed for light microscopy by using a variety of absorption and fluorescent staining methods. The cytochemistry and morphology of development were compared to the well-studied developmental patterns of freshwater sponges and to the patterns described in the marine sponge Suberites domuncula. The precocious development of H. loosanoffi gemmules involves early morphogenesis occurring within the unhatched gemmule, as opposed to the patterns in freshwater sponges, where most development occurs after the gemmule hatches. Definitive sponge tissue surrounding a single osculum is present 9 days after release from dormancy.
    Zusätzliches Material: 25 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930110
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  • 40
    Digitale Medien
    Digitale Medien
    Distribution and innervation of short, interdigitated muscle fibers in parallel-fibered muscles of the cat hindlimb (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 1-15 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The cat hindlimb contains several long, biarticular strap muscles composed of parallel muscle fascicles that attach to short tendons. Three of these muscles -sartorius, tenuissimus, and semitendinosus -were studied by dissecting individual gold-stained fibers and determining the surface distribution of acetylcholinesterase-stained end-plate zones. In each muscle, fascicles were composed of muscle fibers that ran only part of the fascicle length and tapered to end as fine strands that interdigitated with other tapering fibers within the muscle mass. Most muscle fibers measured 2-3 cm in length. Fascicles of muscle fibers were crossed by short transverse bands of endplates (1 mm wide by 1-5 mm long) that were spaced at fairly regular intervals from the origin to the insertion of the muscle. The endplate pattern suggested that the fiber fascicles were organized into multiple longitudinal strips. In the sartorius, the temporospatial distribution of electromyographic (EMG) activity evoked by stimulating fine, longitudinal branches of the parent nerve confirmed that each strip was selectively innervated by a small subset of the motor axons. These axons appeared to distribute their endings throughout the entire length of the fascicles, providing for synchronous activation of their in-series fibers.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910102
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  • 41
    Digitale Medien
    Digitale Medien
    Optimal design of vertebrate and insect sarcomeres (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 49-62 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This paper offers a model for the normalized length-tension relation of a muscle fiber based upon sarcomere design. Comparison with measurements published by Gordon et al. (′66) shows an accurate fit as long as the inhomogeneity of sarcomere length in a single muscle fiber is taken into account. Sequential change of filament length and the length of the cross-bridge-free zone leads the model to suggest that most vertebrate sarcomeres tested match the condition of optimal construction for the output of mechanical energy over a full sarcomere contraction movement. Joint optimization of all three morphometric parameters suggests that a slightly better (0.3%) design is theoretically possible. However, this theoretical sarcomere, optimally designed for the conversion of energy, has a low normalized contraction velocity; it provides a poorer match to the combined functional demands of high energy output and high contraction velocity than the real sarcomeres of vertebrates.The sarcomeres in fish myotomes appear to be built suboptimally for isometric contraction, but built optimally for that shortening velocity generating maximum power. During swimming, these muscles do indeed contract concentrically only. The sarcomeres of insect asynchronous flight muscles contract only slightly. They are not built optimally for maximum output of energy across the full range of contraction encountered in vertebrate sarcomeres, but are built almost optimally for the contraction range that they do in fact employ.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910106
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  • 42
    Digitale Medien
    Digitale Medien
    Lymph heart musculature in birds (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 77-87 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Development and innervation of the lymph heart musculature of chicken, emu, rhea, and duck was studied by electron microscopy at posthatch ages from 3 days to adulthood. Development of innervation was monitored by acetylcholinesterase staining. Horseradish peroxidase was used to determine the extent of the transverse tubule network. Chickens were unusual among these birds in that lymph heart myocytes had already undergone a definitive differentiation and degeneration by 3 days. In ducks and ratite birds, lymph heart myocytes more slowly but progressively differentiate a cytomorphology that does not conform in all characteristics to cardiac or skeletal muscle and even resembles in some aspects, smooth muscle. Myofibrils become the dominant cytoplasmic structure, transverse tubules form ‘internal couplings’ with agranular reticulum cisternae, and ‘external couplings’ are formed between myocytes at myomyal junctions. The myomyal junctions also contain AChE-positive reaction product and some subplasmalemmal vesicles that lack a dense core. The lymph heart myocardium of ducks of 2 weeks demonstrated mitotic figures. In adult ducks the myosatellite cell numbers diminish and a characteristic pattern of myocyte degeneration appears. In juvenile ducks and ratites some myocytes differentiate to conductile cells, much as the conductile myocytes and myofibers of the blood heart. The lymph heart innervation is described, and the role of nerve in differentiation and maintenance of myocyte morphology in the lymph heart is discussed.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910108
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  • 43
    Digitale Medien
    Digitale Medien
    Scanning electron microscopy of vascular corrosion casts of the glomeruli of two species of turtles (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 145-149 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Scanning electron micrographs of microcorrosion casts of the renal vascular system of Pseudemys scripta and Testudo hermanni show fairly well-developed, round glomeruli in the former (mean diameter of casts: 83.1 μm) and fewer but bigger, ovoid glomeruli (mean diameter of casts: 111.1 μm/131.6 μm) in the more arid-adapted. T. hermanni. Furthermore, the intrarenal development of the pertiubular capillary system differs in these two species. These relatively minor morphological differences correlate well with the major differences in the ecology of these species, as well as with physiological data on urine composition from the literature.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910205
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  • 44
    Digitale Medien
    Digitale Medien
    Specializations within the lumbosacral spinal cord of the pigeon (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 41-53 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The prominent accessory lobes of Lachi in birds are considered to be marginal nuclei; similar nuclei have been implicated in mechanoreceptive functions in snakes and lampreys. Reptile studies emphasized the involvement of the denticulate ligament with this mechanoreceptive function. This investigation examines the fine structure of the accessory lobes of Lachi in pigeons and their interaction with ligaments for features which might support such a mechanoreceptive function. In the lumbosacral area of the spinal cord, the lateral longitudinal ligaments and the ventral longitudinal ligament are hypertrophied. The ventral transverse ligaments are present only within the lumbosacral segments of the spinal cord and they interconnect with the lateral and ventral longitudinal ligaments. The lateral longitudinal ligament makes intimate contact with the spinal cord, and many glial processes from the spinal cord mingle with and are firmly attached to collagenous fibers of the ligament. The lobes lie dorsal to the lateral longitudinal ligament in the exact area where it interconnects with the transverse ligament. The lobe's multipolar neurons have a number of synaptic contacts but no unusual specializations were noted. Most of each lobe is composed of interdigitating saccular structures filled to varying degrees with flocculent material. The sacs are extensions of the cytoplasm of neuroglial cells, which also give rise to membranes surrounding neuronal processes and the sacs themselves. A possible functional relationship of the lobes and the ligaments of the lumbosacral spinal segments within the vertebral column is described.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051940104
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  • 45
    Digitale Medien
    Digitale Medien
    Functional characteristics of rat gastrocnemius and tibialis anterior muscles during growth (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 75-84 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Several morphological and functional characteristics of the rat gastrocnemius medialis and tibialis anterior muscle were studied in young, adult, and old rats to assess the influence of growth. Antagonist muscles were studied to determine how changes of muscle architecture and functional characteristics are influenced by the demands of increased body weight and by the specific roles of these muscles in locomotion.Both muscles change drastically, for instance, in muscle length, volume, physiological cross-sectional area aponeurosis length, and their muscular geometry changes allometrically for both muscles. The relationships between muscle length, distance between origin and insertion, tendon length, and tibial length also change with growth. Both muscles are rather pennate, so that the increase of physiological cross-sectional area is a major factor in the determination of muscle length.No significant difference could be shown for fundamental physiological characteristics (i.e., functional characteristics normalized for muscular dimensions such as maximal work per unit volume). The changes of morphological and functional variables of both muscles parallel each other as is apparent from the index of antagonist characteristics, which is constant for all variables studied with the exception of muscle volume and tendon length.Consequently, the considerable and similar changes of TA and GM morphology and functional characteristics that take place during growth from approximately four weeks postnatally is not caused by changes of muscular material but by changes of the amount and architectural arrangement of the material involved.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051940107
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  • 46
    Digitale Medien
    Digitale Medien
    The growth of the skull and jaw muscles and its functional consequences in the New Zealand rabbit (Oryctolagus cuniculus) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 143-161 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Between weaning and adulthood, the length and height of the facial skull of the New Zealand rabbit (Oryctolagus cuniculus) double, whereas much less growth occurs in the width of the face and in the neurocranium. There is a five-fold increase in mass of the masticatory muscles, caused mainly by growth in cross-sectional area. The share of the superficial masseter in the total mass increases at the cost of the jaw openers. There are changes in the direction of the working lines of a few muscles. A 3-dimensional mechanical model was used to predict bite forces at different mandibular positions. It shows that young rabbits are able to generate large bite forces at a wider range of mandibular positions than adults and that the forces are directed more vertically. In young and adult animals, the masticatory muscles differ from each other with respect to the degree of gape at which optimum sarcomere length is reached. Consequently, bite force can be maintained over a range of gapes, larger than predicted on basis of individual length - tension curves. Despite the considerable changes in skull shape and concurrent changes in the jaw muscles, the direction of the resultant force of the closing muscles and its mechanical advantage remain stable during growth. Observed phenomena suggest that during development the possibilities for generation of large bite forces are increased at the cost of a restriction of the range of jaw excursion.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051940204
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  • 47
    Digitale Medien
    Digitale Medien
    The exocrine glands of Dysdercus cingulatus (Heteroptera, Pyrrhocoridae): Morphology and function of nymphal glands (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 195-207 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The exocrine glandular system of the nymphs and the adults of Dysdercus cingulatus were studied. The D. cingulatus nymphs present 3 dorso-abdominal glands (lying under the 3rd, 4th, and 5th abdominal terga) and a pair of dorso-lateral pygidial glands on the pygidium (tergum 8). Histological and ultrastructural studies show that the upper and lower walls of the dorso-abdominal glands differ in structure; 3 types of cells were described: epidermal cells, unicellular secretory cells, and multicellular secretory units. Each of these exocrine glands plays an important part in the behavior of the nymphs (gregariousness, alarm, defense). The morphology of the various glands is discussed, and the chemistry of their secretions and their biological functions are considered.
    Zusätzliches Material: 30 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051940208
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  • 48
    Digitale Medien
    Digitale Medien
    Comparative aspects of cerebellar cytoarchitecture in the European eel life cycle (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 25-36 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The major anatomical divisions of the cerebellum of the European eel, i.e., corpus cerebelli, lobus vestibulolateralis, and valvula, were studied morphologically and morphometrically. There were differences in cerebellar cytoarchitecture and gross morphology in two stages of the eel life cycle, the trophic stage (yellow eel), and the reproductive stage (silver eel), which are characterized by different degrees of swimming activity. The principal differences between silver and yellow eels in the cytoarchitecture of the corpus cerebelli and the lobus vestibulolateralis were in distribution of Purkinje or Purkinje-like cells in the molecular layer, which is wider in silver eels, in part because of a decreased thickness of the granular cell layer. In the silver eel, the scattering of Purkinje cells was more evident in the lobus vestibulolateralis where the molecular layer is also thicker. The data indicate the transition from the yellow eel to the silver eel is characterized by a migration of granule cells from the ganglionic cell layer to the internal granular layer and by a further development of molecular layer components, e.g., parallel fibers, Purkinje-cell dendrites, etc. In contrast, the thickness of the granular layer and of the Purkinje cell layer, limited to the lower part of the valvula, decreased. There is also a slight increase of cerebellar volume in the silver eel. The volume of the lobus vestibulolateralis was constant. Hypertrophy of the valvula and eminentiae granulares is observed and is due to the migration of cells from the granular layer of the corpus cerebelli whose volume slightly decreases. Perhaps the lobus vestibulolateralis also contributes to the increased volume of eminentiae granulares. Our findings suggest that the cerebellum continues to develop during the passage from the trophic to the reproductive stage of the eel. The appearance of new afferents from the lateral line which becomes more visible in the silver eel probably completes cerebellar ontogeny.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910104
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  • 49
    Digitale Medien
    Digitale Medien
    Announcement (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 107-107 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910110
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  • 50
    Digitale Medien
    Digitale Medien
    Regenerative response of amputated forelimbs of Xenopus laevis froglets to partial denervation (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 131-144 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Xenopus laevis froglet forelimbs normally respond to amputational injury by forming a heteromorphic cartilaginous rod-shaped outgrowth. However, partial denervation of a forelimb by ablation of the N. radialis or the N. ulnaris, followed in 2 days by amputation through the mid radius-ulna, results in a size deficiency of the regenerative outgrowth 14 and 21 days postamputation. The decreasing quantity of forelimb innervation, as a result of partial denervation by 55 or 45%, apparently has a graded effect on the cell population and on the extent of cartilage development in the outgrowth. As a consequence of amputational injury, a nerve independent response of the periosteum was also found. This response produced considerable thickening in the periosteum and was due to cell proliferation in both the control and denervated cases.
    Zusätzliches Material: 17 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910204
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  • 51
    Digitale Medien
    Digitale Medien
    A morphological study of the nervous system of the praesoma of Paulisentis fractus (Acanthocephala: Neoechinorhynchidae) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 193-204 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The nerve pathways in the praesoma are described for a member of the class Eoacanthocephala for the first time. Eleven nerves, five paired and one single, are traced from the cerebral ganglion to their associations with the musculature of the body wall, neck sense organs, and the musculature of the proboscis wall and the invertor muscles of the proboscis. The structure and location of the stutzzelle and series of nerve endings in the hypodermis of the body wall and at the apex of the proboscis are described.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910209
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  • 52
    Digitale Medien
    Digitale Medien
    List of reviewers (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 215-216 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910302
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  • 53
    Digitale Medien
    Digitale Medien
    Intrafusal muscle fibers of duck muscle spindles (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 225-232 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Serial transverse paraffin sections of intrafusal muscle fibers of spindles from the extensor pollicis and the extensor digitorum communis of ducks show that only one type of intrafusal muscle fiber exists, based on the mid-equatorial nucleation pattern, diameter, and length. Although the overall range in fiber diameter at the mid-equatorial region is between 4.2-20.0 μm, the average caliber is 10.4 ± 3.18 μm (S.D.) for spindles of the extensor pollicis and 9.3 ± 2.11 μm (S.D.) for spindles of the extensor digitorum communis muscles. The range in spindle length for the extensor pollicis is 290-2,090 μm, average 1,120 ± 569 μm (S.D.), and for the extensor digitorum communis 1,160-2,500 μm, average 1,745 ± 367 μm (S.D.). Therange in number of fibers per spindle for the extensor pollicis muscle is 5-12, average 8.2, and for the extensor digitorum muscle it is 1-11. In the extensor digitorum communis, there appear to be two groups, based on fiber number. Spindles of one group have a range of 5-11 fibers per spindle with an average of 7.2, whereas the second group has a range of 1-4 with an average of 2.7 fibers per spindle. The second group of spindles constitutes 52.5% of the 40 spindles studied, and of these 7.5% were monofibril spindles, 15.0% difibril, 17.5% trifibril, 12.5% quadrifibril spindles.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910304
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  • 54
    Digitale Medien
    Digitale Medien
    Masthead (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920101
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  • 55
    Digitale Medien
    Digitale Medien
    Ultrastructure of the larval salivary glands of Megaselia scalaris Loew (Diptera, Phoridae) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 265-288 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Each of the paired salivary glands of third instar larvae of the humpbacked fly Megaselia scalaris is a bag-like structure with a short neck region from which a single duct emerges. The two ducts form a common duct that empties into the ventral region of the pharynx near the mouthparts. The wall of the glands and ducts consists of a simple squamous epithelium that rests upon a connective tissue layer. Cells in the neck are less flattened than those found elsewhere. The basal surfaces of the cells are infolded most deeply in the neck and the least in the duct. The apical surfaces of the cells possess microvilli except in the duct where the apices of the cells are covered by a complex extracellular layer. This layer displays circularly arranged folds that accommodate a thread-like supportive structure resembling taenidial threads of tracheae. Elaborate junctional complexes are associated with the lateral surfaces of the cells. Elements of these complexes include a zonula adherens, a series of pleated septate desmosomes, and conventional desmosomes. The cytoplasm of the glandular cells is filled with RER and other organelles normally seen in cells that export proteins and mucosubstances. Secretory material found in the lumens of the glands reacts only moderately with the PAS procedure but more strongly with alcian blue and methods that demonstrate proteins. The nuclei of the glandular cells contain single large nucleoli and polytene chromosomes whose banding is rather indistinct. Treatment with EDTA produces detrimental effects on all of the foregoing ultrastructural features of the glands and ducts.
    Zusätzliches Material: 55 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910307
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  • 56
    Digitale Medien
    Digitale Medien
    Cellular dynamics of conjugation in the ciliate euplotes aediculatus. I. Cytoskeletal elements (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 27-42 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The fate and possible roles of the cytoskeleton in the process of conjugation in the hyptrich ciliate Euplotes aediculatus were investigated. Following the coalescence of the plasma membranes of the conjugant cells, a fusion zone or bridge of cytoplasm contributed by both partners is constructed. The sub-alveolar microtubule layers of the vegetative cell cortex remain in place to define the fusion zone boundaries after cell union. The initial fusion zone consists primarily of featureless ground cytoplasm; soon the ground plasm becomes crowded with microtubules and anastomosing smooth endoplasmic reticulum, which become displaced only late in conjugation as the migratory pronuclei are exchanged between partners. Fusion zone microtubules, functioning in some undetermined way, may be involved in the nuclear migration. Resorption of the posterior portion of each partner's buccal apparatus results in the degradation of the component cilia within acid phosphatase-positive autophagic bodies. Silver staining for light microscopy shows that the late fusion zone contracts forward from the posterior border, then constricts to separate the conjugants. In some separating pairs remnants of a microfilamentous assembly are seen at the posterior edge of the fusion zone; the full extent of this system may be masked by partial degradation due to osmium tetroxide fixation. Treatment of conjugants for 6 hours with cytochalasin B prevents separation, possibly through inhibition of the actin-like microfilament assembly in the fusion zone. The observations and experiments favor a model of cell separation following conjugation in which the fusion zone is resorbed by motile or contractile processes occurring within or around the fusion bridge itself.
    Zusätzliches Material: 21 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920104
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  • 57
    Digitale Medien
    Digitale Medien
    Tentacle development in dermophis mexicanus (amphibia, gymnophiona) with an hypothesis of tentacle origin (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 101-111 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The development of the tentacle, a chemosensory and perhaps tactile structure unique among vertebrates to gymnophione amphibians is described in Dermophis mexicanus and Gymnopis multiplicata. The tentacle is associated with the vomeronasal organ and its glands, and utilizes several structures usually associated with the eye, such as the Harderian gland, the retractor and levator muscles, and their nerves. Innervation of the tentacle itself is from the trigeminal nerve. We present an hypothesis that the tentacle originated from modified eye components.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920203
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  • 58
    Digitale Medien
    Digitale Medien
    Spicule formation in the solitary ascidian, herdmania momus (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 145-159 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Two types of calcareous spicules occur abundantly in Herdmania momus, a solitary pyurid ascidian with a worldwide warm water distribution. The large spindle-shaped body spicules are 1.5-2.5-mm long and are located primarily in the mantle, siphons, and branchial basket. Each body spicule possesses 100 or more rows of overlapping, unidirectional fringing spines. Numerous body spicules occur regularly spaced within a long common sheath of complex structure, and there are many sheaths per animal. Between neighboring body spicules and overlying the fringing spines are the tightly connected pseudopodial sclerocytes. Spine formation is hypothesized to occur within these cells. The body spicules apparently continue to increase in size throughout the animal's life.The tunic spicules are about one tenth the length of the body spicules. They have 20-40 rows of unidirectional nonoverlapping fringing spines and a mace-shaped spiny base that anchors them at the tunic surface. They form quickly in individual spicular envelopes inside the tunic blood vessels over a 4-5-day period. Each tunic spicule then leaves its surrounding envelope and blood vessel, passes into the tunic, and ultimately protrudes through the outer surface of the tunic. An organic covering inside the envelope closely adheres to the tunic spicules and stains with toluidine blue. Dissolution of the CaCO3 mineral phase by EDTA or EDTA-cetylpyridinium chloride-formaldehyde reveals an intricately patterned organic matrix within or upon which the spicules develop.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920206
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  • 59
    Digitale Medien
    Digitale Medien
    Characterization of the form and growth pattern of colonies in several freshwater bryozoans (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 161-179 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In all species of phylactolaemates, an individual successively produces daughter buds. Individual daughters are designated, according to the order of appearance, as first bud, second bud, and so on. The first bud appears precociously, while the mother is a pear-shaped vesicle. The idea of regarding a main bud, a duplicate bud, and an adventitious bud as a set is not tenable. In the budding region, the cystidal wall shows a constant wavy movement. In Plumatella colonies, branching occurs only when and where a bud of the second or higher order grows up to a zooid. A branch is composed of longitudinally arranged first zooids with the only exception being the most proximal one. The proportion of first zooids in a colony increases in the order of P. casmiana, P. emarginata, and P. repens. The frequency of branching, therefore, decreases in this order. The ancestrula germinated from the statoblast shows the highest activity of budding. The tendency that successively produced daughters of the ancestrula grow in alternate directions is most conspicuous in P. emarginata and least conspicuous in P. casmiana. Replacement budding occurs in these three species of Plumatella, but only under unfavorable culture conditions. The colony of Gelatinella toanensis is characterized by composite branches, each consisting of an axial branch composed of a series of first zooids and of stunted lateral branchlets. In Hyalinella punctata, multiple budding does not necessarily result in branching; zooids of different budding orders coexist in a branch. The genus Pectinatella comprises two species, P. gelatinosa and P. magnifica. Both produce massive colonies. In P. gelatinosa, the colony proper is sac-like with the convex basal wall, and the polypides can retract with the digestive tracts straight. Each individual (except the ancestrula) of this species produces a pair of daughter buds which are located bilaterally relative to the median sagittal plane of the mother. A left bud produces its first bud to the right, and vice versa. In P. magnifica, the colony proper is very thin and flat. When polypides are retracted, the digestive tracts are folded characteristically. Based on these and other results, phylogenetic relationships among the phylactolaemates are discussed.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920207
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  • 60
    Digitale Medien
    Digitale Medien
    Somatic tissue-male germ cell barrier in three hermaphrodite invertebrates: Dugesia biblica (Platyhelminthes), Placobdella costata (Annelida), and Levantina hierosolyma (Mollusca) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 217-227 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The gonads from three hermaphrodite species of different invertebrate phyla were studied at the ultastructure level. In the flatworm Dugesia biblica, male germ cells in different stages of development lay in the lumen of testicular follicles surrounded by overlapping parietal cells. The intercellular space formed by cytoplasmic extensions running parallel to the testis wall is occluded by septate junctions and by an electron-dense material. In the leech Placobdella costata, the testis is lined by a unicellular layer of parietal cells surrounded by densely packed connective tissue fibers. No specialized occluding junctions were found between the parietal cells; however, plasmalemma thickenings and electron-dense material in the intercellular space near to the testis lumen were observed. In the lumen, germ cells develop connected to cytoplasmic masses, the cytophore. In the land snail Levantina hierosolyma, male and female germ cells are found together in the same acini; each acinus is surrounded by a thick basement membrane. At the periphery of the acinus is the ovarian layer; centrally to it is the testicular layer. Intercalated between them is a double cellular layer of follicular cells and of Sertoli cells. The inter-Sertoli space is characterized by elaborate septate junctions. In the three species studied male germ cells develop within the lumina of compartments isolated from the somatic tissue. This separation is brought about by specialized septate junctions, and/or by electron-dense material between the cells that form the testis walls, and also by densely packed connective tissue fibers. Our observations strengthen the view that a male germ cell-somatic tissue barrier as described in the literature of the testes of vertebrates and of invertebrates from various phyla is of general occurrence in the animal kingdom.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920304
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  • 61
    Digitale Medien
    Digitale Medien
    Oogenesls in the terrestrial hermit crab, coenobita clypeatus (decapoda, anomura): II. Vitellogenesis (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 269-277 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Oocytes from the land hermit crab, Coenobita clypeatus, in various stages of vitellogenesis were examined by light and electron microscopy. Early vitellogenic oocytes are characterized by accumulations of discrete vesicles of endoplasmic reticulum in the perinuclear cytoplasm. As oocytes develop, the endoplasmic reticulum becomes abundant, and numerous Golgi complexes are seen. There is a well developed Golgi-endoplasmic reticulum interaction. Within the confines of the reticulum are discrete intracisternal granules, which can be seen coalescing into electron-dense yolk bodies. Lipid accumulation is seen throughout the cytoplasm. Coincident with the burst of intra-oocytic metabolism are oolemma modifications and micropinocytosis, which provide ultrastructural evidence for extra-oocytic yolk production. The mature oocyte contains numerous yolk and lipid vesicles of varying electron density that comprise both intra- and extra-oocytic substrates.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920309
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  • 62
    Digitale Medien
    Digitale Medien
    Masthead (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930101
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  • 63
    Digitale Medien
    Digitale Medien
    Structure and function of the spermatheca in a snail host of schistosomiasis, Biomphalaria glabrata (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 295-308 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The histochemistry and ultrastructure (SEM and TEM) of the spermatheca of Biomphalaria glabrata was investigated to elucidate the function of this organ and to compare its structure and function to similar organs found in other species. The spermatheca has a debris-filled lumen surrounded by a thin wall of tissue. The cells adjacent to the lumen are of three columnar epithelial cell types. Two cell types have abundant microvilli and mammalian cell-like organelle distribution and morphology. The above cell types differ in the electron density of their cytoplasms, nuclear morphologies, and organelle content. The third cell type differs from the other two in its cytoplasmic makeup. However, the most distinctive difference is the presence of large numbers of cilia at the apical surface with no evidence of microvilli. These columnar cells rest on a basal lamina adjacent to a two to three cell thick muscle layer. The entire organ is surrounded by an adventitia of unusual morphology. Histochemical investigation demonstrated that DNAase, RNAase, and protease are present in the lumen, alkaline phosphatase is associated primarily with the microvilli, small amounts of acid phosphatase are concentrated in the midcell area of the columnar epithelium, and ATPase activity is localized in the muscle cells and just below the absorptive surface of the microvillous cells. The luminal contents and adventitial areas are Sudan Black B positive, all areas of the lumen and organ wall are PAS positive, the cell nuclei and amorphous masses in the lumen showed Feulgen staining, and large vesicles in the columnar cells were Oil Red O positive. Apparently, the spermatheca of B. glabrata is both a digestive and absorptive structure. Although this organ shares functional similarities with those found in opisthobranchs and terrestrial pulmonates, the epithelia of the spermatheca differ dramatically in these groups.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910309
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  • 64
    Digitale Medien
    Digitale Medien
    Masthead (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920201
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  • 65
    Digitale Medien
    Digitale Medien
    Allometry of the limb long bones of insectivores and rodents (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 113-123 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In an attempt to investigate the relationships between allometry and locomotory adaptations, we studied the long limb bones of 45 species of insectivores and rodents. Animals ranged from a few grams to about 50 kilograms. Diameter and length of the bones and body mass (when known) were recorded. Regressions of diameter to length, diameter to body mass, and length to body mass were calculated by the least-squares and Model II, or major axis, methods.The results obtained do not agree with the predictions of either the theory of geometric similarity or the theory of elastic similarity. The discrepancies could be due to the fact that animals studied exhibit various modes of locomotion. Moreover, the allometric relationships of the different locomotor patterns are better reflected in insectivores and rodents than in other groups of mammals. The use of a single regression analysis seems to be inadequate when the sample includes a large range of body sizes.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920204
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  • 66
    Digitale Medien
    Digitale Medien
    Morphology of chemosensory organs required for feeding in the leech hirudo medicinalis (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 181-187 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Sensilla that line the upper edge of the lip in the leech Hirudo medicinalis and that contain chemoreceptors required for feeding were examined in the scanning and transmission electron microscopes. The sensilla include two size-classes of ciliated button-like mounds - one about 35 μm in diameter and another about 10 μm in diameter. The larger sensilla are at the center of unpigmented patches of skin which are visible in the light microscope, while the smaller sensilla have not been previously described as distinct structures. Electron microscopy, though not light microscopy, shows that the lip sensilla differ markedly from the segmental sensilla of the leech, which have been shown to mediate mechanoreception and photoreception. In particular, the chemosensory lip sensilla contain multiciliated cells with cilia of a uniform length, whereas the segmental sensilla contain uniciliated cells with long, whip-like cilia, as well as multiciliated cells with short, stiff cilia. Thus, the two types of sensilla differ morphologically as well as functionally. In addition to the ciliated sensilla along the upper lip, structures consisting of a short, club-like process surrounded by granular material were observed inside the mouth. These structures may also be chemosensory organs.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920208
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  • 67
    Digitale Medien
    Digitale Medien
    Structure of hematopoietic nodules in the ridgeback prawn, Sicyonia ingentis: Light and electron microscopic observations (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 193-204 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The architecture and fine structure of the epigastric hematopoietic nodules of the ridgeback prawn, Sicyonia ingentis, are described. The nodules consist of a highly branched series of tubules that contain the maturing hemocytes within a connective tissue stroma. Hemocytes can exit the hematopoietic nodules by penetrating through fenestrations in the endothelial cell layer into the central hemal space or by migrating through the outer later of capsular cells and associated collagen fibrils. Four hemocyte categories were observed: agranular, small granule with cytoplasmic deposits, small granule without cytoplasmic deposits, and large granule hemocytes. This classification was based upon the presence, size, and type of cytoplasmic granules and the presence of cytoplasmic deposits. Only agranular cells and small granule hemocytes without cytoplasmic deposits appeared capable of division. Intermediate stages were observed between agranular hemocytes and small granule hemocytes with deposits and between small granule hemocytes without deposits and large granule hemocytes, suggesting existence of two distinct hemocyte lines.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920302
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  • 68
    Digitale Medien
    Digitale Medien
    Submandibular duct salivary bladder of the rat (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 247-256 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This investigation is a light and electron microscopic description of the submandibular duct salivary bladder of the rat, a dilation of the distal end of the main excretory duct. The wall of the bladder consists of (1) a mucosa with pseudostratified epithelium, (2) a submucosal layer of connective tissue, and (3) an underlying layer of striated muscle. The pseudostratified columnar epithelium lining the bladder is composed of three cell types: (1) light cells, (2) dark cells, and (3) basal cells. The lamina propria contains bundles of collagen, attenuated fibrocytes, capillaries with fenestrated endothelia, and nerve fibers which enter the epithelial layer. The capillaries of the submucosa are not fenestrated. The morphology of the wall of this structure provides evidence that the primary fluid of the submandibular gland is modified in the bladder by transepithelial fluid and ion transport.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920307
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  • 69
    Digitale Medien
    Digitale Medien
    Histochemistry of the lung of the Australian snake-necked tortoise chelodina longicollis (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 257-268 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The innervation and structure of the lung of the Australian snake-necked tortoise, Chelodina longicollis, was examined by using light microscopy including fluorescence histochemical techniques. The anterior lung was divided into a number of compartments with numerous alveolar spaces. The posterior lung was simpler and saclike in structure and alveolar spaces were absent. Smooth muscle fibers occurred in discrete muscle bands and in the walls of the septal bands. Ganglion cells occurred along nerve trunks throughout the lung but were more numerous in the posterior lung. Smooth muscle bands, the extrinsic pulmonary artery, and the arteries within the lung were sparsely innervated by adrenergic fibers. Substance P-containing sensory fibers were not demonstrated. The innervation and structure of the lung are compared to published work on other reptiles.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920308
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  • 70
    Digitale Medien
    Digitale Medien
    Ultrastructural changes in the intestinal connective tissue of Xenopus laevis during metamorphosis (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 13-22 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Ultrastuctural changes in the intestinal connective tissue of Xenopus laevis during metamorphosis have been studied. Throughout the larval period to stage 60, the connective tissue consists of a few immature fibroblasts surrounded by a sparse extracellular matrix: few collagen fibrils are visible except close to the thin basal lamina. At the beginning of the transition from larval to adult epithelial form around stage 60, extensive changes are observed in connective tissue. The cells become more numerous and different types appear as the collagen fibrils increase in number and density. Through gaps in the thickened and extensively folded basal lamina, frequent contacts between epithelial and connective tissue cells are established. Thereafter, with the progression of fold formation, the connective tissue cells become oriented according to their position relative to the fold structure. The basal lamina beneath the adult epithelium becomes thin after stage 62, while that beneath the larval epithelium remains thick. Upon the completion of metamorphosis, the connective tissue consists mainly of typical fibroblasts with definite orientation and numerous collagen fibrils. These observations indicate that developmental changes in the connective tissue, especially in the region close to the epithelium, are closely related spatiotemporarily to the transition from the larval to the adult epithelial form. This suggests that tissue interactions between the connective tissue and the epithelium play important roles in controlling the epithelial degeneration, proliferation, and differentiation during metamorphic climax.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930103
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  • 71
    Digitale Medien
    Digitale Medien
    Fine structure of the gene's organ in the camel tick Hyalomma (Hyalomma) dromedarii (Ixodoidea: Ixodidae) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 91-98 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Gene's organ of the camel tick Hyalomma (Hyalomma) dromedarii is located in the anterodorsal region of the body cavity ventrad to the scutum. It consists of a short stalk, dividing posteriorly into 2 pairs of horns and then into tubular glands. In unfed ticks, the eipithelial layer of both the stalk and horns is lined internally by 2 cuticular layers; an inner, thin, greatly folded, dense layer surrounds the organ main lumen, and an outer, thick, slightly folded, less dense layer abuts the cell apices. Only the inner cuticular layer extends into the horn posterior region and appears perforated with numerous pore canals and covered with fine, cuticular projections. The horn and tubular glands epithelium is structurally consistent with a secretory function that apparently increases as feeding progresses. During oviposition, the inner cuticular layer unfolds and inflates into a pair of balloonlike structures that evert through the organ external aperture to receive and manipulate each egg as it is laid, coating it with a waxy layer that prevents desiccation. The fine cuticular projections may have a function in gripping the eggs as they leave the vagina. This organ appears to be everted by hydrostatic pressure from the hemolymph and is retracted by muscles.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930109
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  • 72
    Digitale Medien
    Digitale Medien
    Development of the head skeleton of the Japanese medaka, Oryzias latipes (Teleostei) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 135-158 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The identification, spatial relationships, and sequences of development of the cartilaginous and bony elements of the chondrocranium, osteocranium, and splanchnocranium in the medaka, Oryzias latipes, are described here for the first time. The development of the cartilaginous head skeleton commences at stage 29 and is essentially complete by stage 35 (hatching). The parasphenoid bone and two pairs of branchiostegals are present at this stage and several other replacement and dermal bones begin to appear shortly thereafter. Development of the osteocranium and ossification of the splanchnocranium continue throughout the larval and juvenile phases and are essentially complete at sexual maturity at approximately 3 months (at 25°C), at which time the fish range in length between 25 and 30 mm.The description of the adult head skeleton of O. latipes is compared to those of O. melastigma, O. luzonesis, and other Oryzias spp. previously described and a redesignation of the relationships between certain elements in the adult head skeleton is proposed, based on the developmental data presented. Furthermore, the value of the medaka as a model teleost to study the embryological origins of, and in particular, the neural crest contributions to, the cranial and visceral skeleton is outlined based on certain characteristics of the medaka's life history traits. These include the ease of obtaining embryos for which the exact time of fertilization is known (without sacrificing any brood stock) and the relatively rapid development of the chondrocranium, which is nearly complete at hatching, a process which can occur in as short a time as 6 days (at 34°C). The usefulness of the ontogenetic data obtainable from further studies into the embryonic origins of head and visceral skeletal elements revealed in the present study, is briefly discussed.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930203
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  • 73
    Digitale Medien
    Digitale Medien
    Fertilization and aqueous development of the puerto rican terrestrial-breeding frog, Eleutherodactylus coqui (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 217-224 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The Puerto Rican tree frog, Eleutherodactylus coqui, has internal fertilization and direct development on land. In light of these reproductive adaptations, the events of fertilization and early development were studied. Cytological examination of just-fertilized eggs showed that sperm entry is restricted to about 10% of the surface of these large, yolky eggs, and all nuclear events of the first cell cycle occur near the animal pole. Although the oocytes have cortical granules, a number of polyspermic fertilizations were found. One clutch consisted of eggs with a high frequency of polyspermy and of normal development. This raises the possibility that normal development can occur despite multiple sperm entry, a situation not found in other anuran amphibians. With respect to saline requirements, the sperm and the embryo are similar to those in amphibians with external fertilization and aqueous development. Sperm motility was high in low-tonicity conditions, and the normally terrestrial embryo could develop completely from a fertilized egg to a froglet in a low-tonicity aqueous solution.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930208
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  • 74
    Digitale Medien
    Digitale Medien
    Regeneration of the eighth nerve fibers after transection in the red-eared turtle, Chrysemys scripta elegans (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 197-216 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The present study examined the time sequence of degeneration and regeneration after transection of the eighth nerve in the red-eared turtle as well as the chromatolytic reaction of the turtle auditory ganglion cells. Horseradish peroxidase (HRP) transport between auditory ganglion cells and the medulla identified eighth nerve connections. The course of eighth nerve degeneration was followed with Fink and Heimer degeneration stain and HRP reaction. Cresyl-violet-stained sections through auditory ganglion cells were observed for chromatolysis.Degeneration by-product was intense in the eighth nerve and primary auditory nuclei in turtles surviving 25 and 32 days after eighth nerve transection. Turtles surviving 45 days or less after eighth nerve transection showed HRP reaction product in the eighth nerve to the point of its dorsolateral penetration into the medulla following cochlear duct injections. Acoustic tubercle injections in 50-day survivors showed HRP filling in eighth nerve and auditory ganglion cells. Cochlear duct injections in 67-day survivors demonstrated HRP filling in the eighth nerve and acoustic tubercle. Sections stained for degeneration in 67-day survivors showed little or no degeneration by-product and 80- and 90-day survivors showed none.The proportion of chromatolytic auditory ganglion cells was greatest in the 50-day postoperative turtles when compared to control turtles and other survival stages. Animals which survived longer than 50 days had reduced numbers of chromatolytic cells.Results suggest that the eighth nerve fibers are regenerated to primary brainstem auditory nuclei in experimental turtles surviving 50 days or more. Regeneration occurs between the 45th and 50th day following transection.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930207
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  • 75
    Digitale Medien
    Digitale Medien
    Development of an avascular region (the stigma) in ovarian follicles of lizards (Anolis) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 311-322 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The architecture of follicular blood vessels in the ovary of lizards (Anolis equestris and Anolis carolinensis) was studied by standard histology and also after vascular perfusion with an orange silicone-rubber compound or with India ink. The theca of the follicular wall contains a netlike arrangement of anastomosing sinusoids, which increase in size as a follicle grows. An avascular stigma forms in very small, growing follicles when a portion of the follicular wall contacts the ovarian surface epithelium. Blood vessels then invade the theca except in the zone of contact. The diameter of the stigma is about 50% of follicular diameter, regardless of follicular size. Although the stigma of smaller follicles is avascular, that of vitellogenic follicles is hypovascular, i.e., a few vessels radiate into the stigma region. The antiangiogenic process involved in stigma formation may continue as the stigma enlarges. The development pattern of stigma formation found in Anolis is displayed by many other vertebrates.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051940310
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  • 76
    Digitale Medien
    Digitale Medien
    Neuromast topography in anuran amphibians (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 115-129 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Generalized anuran tadpoles across families exhibit a similar neuromast morphology on their heads, as follows: (1) all neuromast lines known for anurans are present; (2) within these lines total neuromast number ranges from about 250 to 320; (3) neuromasts form linear stitches composed of two to three, but sometimes up to five, neuromasts; (4) neuromast linear dimensions are ≤ 10 μm; and (5) neuromasts contain ≤ 15 hair cells. Compared with generalized forms, stream, arboreal, carnivorous, and desert-pond forms have fewer neuromasts but they contain more hair cells. They do not, however, form stitches. Obligate midwater suspension-feeding forms, including Xenopus (Pipidae), Rhinophrynus (Rhinophyrnidae), and Phrynomerus (Microhylidae), form stitches that contain 〉 six, but potentially up to 18 or more, loosely aggregated neuromasts. Xenopus and Rhinophrynus have large neuromasts (up to 40 μm across). Chiasmocleis (Microhylidae) tadpoles form stiches that are linearly arranged with up to ten neuromasts. Whereas urodeles can have more than one neuromast row per line and may form both linear and transverse stitches, anurans have only one row of neuromasts per line and form only transverse stitches. Neuromasts in anurans tend to be smaller and more circular than in urodeles and positioned flush with the epidermal surface. A greater percentage of anurans form stitches, and anurans have greater intrafamilial variation in stitch formation than do urodeles.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910203
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  • 77
    Digitale Medien
    Digitale Medien
    An anatomical and functional analysis of cat biceps femoris and semitendinosus muscles (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 161-175 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The anatomy, architecture, and innervation patterns of the hamstring muscles, biceps femoris, and semitendinosus were examined in adult cats using microdissection and glycogen-depletion techniques. The biceps femoris muscle consists of two heads. The anterior head, which attaches mainly to the femur, is divided into two parts by the extramuscular branches of its nerve. The posterior head is innervated by a single nerve. Semitendinosus is composed of two heads, one proximal and one distal to a tendonous inscription, each of which is separately innervated. The extramuscular branches of the nerves to these hamstring muscles thus partition them into innervation subvolumes termed parts. The available evidence suggests that each of the parts of these muscles so innervated is not equivalent to the collections of single motor units that have been described for ankle extensors as neuromuscular compartments. It is quite likely that each of the parts of the hamstring muscles may contain more than one neuromuscular compartment. Using chronically implanted EMG electrodes, the activation patterns of different parts of the hamstring muscles were analyzed during locomotion. The anterior and middle parts of biceps femoris are active during the early stance phase, probably producing hip extensor torque. The posterior part of biceps femoris and semitendinosus act most consistently as flexors, during the early swing phase, but also may function in synergy with hip, knee, and ankle joint extensors near the time of foot placement. Greater variability is found in the activity patterns of posterior biceps femoris and semitendinosus with respect to the kinematics of the step cycle than is observed for anterior and middle biceps femoris. It is suggested that this variation may reflect a larger role of sensory feedback in shaping the timing of activity in posterior biceps femoris and semitendinosus than in ‘monarticular’ muscles.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910207
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  • 78
    Digitale Medien
    Digitale Medien
    Ultrastructure of the venous ampulla in the interradicular microvascular bed of the mandibular molars of Mus musculus (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 217-224 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The interradicular periodontal ligament of mandibular molars contains an apparently unique dilated vessel straddling the interradicular alveolar bone. This structure is designated a venous ampulla. The vessel possesses a luminal length and width of approximately 200 × 100 μm, respectively. Ultrastructurally, the endothelium has an average thickness of 0.35μm, a continuous basement membrane, and an incomplete layer of pericytes. Open endothelial junctions are not present. The anatomy of the vessel wall differs markedly on the dental- and bone-related aspects. Calculated ratios for the luminal diameter to wall thickness vary from 1:80 to 1:150. Postcapillary-sized limbs from this vessel drain into the interradicular septum of bone and the ligament microvascular bed. Arterial supply to the ampulla is provided via arteriovenous anastomoses characterized by their association with myelinated and unmyelinated nerve groups.Oxytalan fibers are present throughout the wall of the venous ampulla, penetrating to the abluminal side of the endothelium where they are associated with unmyelinated axons and free nerve endings. Elsewhere, oxytalan fibers are related to the arteriovenous anastomoses and their accompanying myelinated and unmyelinated nerves located adjacent to the endothelium. Pericytes form membranous contacts with the endothelium of the arteriovenous anastomoses and have processes penetrating the endothelium basement membrane.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910303
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  • 79
    Digitale Medien
    Digitale Medien
    Hemocytes and granular cell fragments of Tipula paludosa larvae (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 191 (1987), S. 289-294 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Five morphological categories of hemocyte (prohemocyte, ameboid plasmatocyte, spindle-shaped plasmatocyte, oenocytoid, and granular cell) were observed by light and electron microscopy of hemolymph from Tipula paludosa larvae. In addition, vast numbers of membrane-bounded granule-containing fragments were present, and were also found in the larval hemolymph of four other Tipula spp. The fragments appear to be derived from the granular cells, which readily fragment. Granules in the granular cells and the fragments appear to have similar substructure. Melanization and coagulation of the hemolymph occur rapidly on exposure to air; the granular cell fragments may be concerned with one or both of these processes.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051910308
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  • 80
    Digitale Medien
    Digitale Medien
    Characteristic features in the formation of anuran sound-conducting systems (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 1-11 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The middle ears of some species of anurans display a set of features that are derived. Some of these features have obvious adaptive significance, whereas the adaptive significance of other derived features is rather obscure. The sequence of histological differentiation of the elements of the derived anuran middle ear, as well as the pattern of morphological changes in their shape, were analyzed and compared with the morphogenesis of the generalized middle ear. Most of the derived features are paedomorphic characters associated with truncated development. The accelerated rate of the opercular development, together with the delayed initiation of function in the tympanic system, permit heterochronic development phenomena to affect the formation of anuran sound-conducting systems.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920102
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  • 81
    Digitale Medien
    Digitale Medien
    Cellular dynamics of conjugation in the ciliate euplotes aediculatus. II. Cellular membranes (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 43-61 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The formation and subsequent dissolution of a common bridge of cytoplasm between conjugating ciliated protozoan cells provides an excellent opportunity to follow the dynamics of the cellular membrane systems involved in this process. In particular, separation of conjugant partners offers the chance to observe, at a fixed site on the cell surface, how the ciliate surface complex of plasma and alveolar membranes (collectively termed the “pellicle”) is constructed. Consequently, cortical and cellular membranes of Euplotes aediculatus were studied by light and electron microscopy through the conjugation sequence. A conjugant fusion zone of shared cytoplasm elaborates between the partner cells within their respective oral fields (peristomes) to include microtubules, cytosol, and a concentrated endoplasmic reticulum (heavily stained by osmium impregnation techniques) that may also be continuous with cortical ER of each cell. Cortical membranes displacd by fusion are autolyzed in acid phosphatase-positive lysosomes in the fusion zone. As conjugants separate, expansion of the plasma membrane may occur through the fusion of vesicles with the plasma membrane, presumably at bare membrane, presumably at bare membrane patches near the fusion zone. The underlying cortical alveolar membranes and their plate-like contents are reconstructed beneath the plasma membrane, apparently by multiple fusions of dense-cored alveolar precursor vesicles (APVs). These precursor vesicles themselves appear to condense directly from the smooth ER present in the fusion zone. No Golgi apparatus was visible in the fusion zone cytoplasm, and no step of APV maturation that might involve the Golgi complex was noted.
    Zusätzliches Material: 22 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920105
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  • 82
    Digitale Medien
    Digitale Medien
    Functional bases of fiber length and angulation in muscle (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 63-85 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The differences in angulation and length observed for the fibers of anatomical muscles may reflect two distinct mechanical requirements: (1) arrangement for pinnation, reflecting an increase in physiological crosssection and (2) arrangement for equivalent placement of sarcomeres, possibly associated with coordination. The observed differences in fiber angulation and length have different effects upon the responses of sarcomeres, specifically on their extent and rate of shortening and on the force they may generate. The basic mechanisms governing these effects and the various arrangements of muscles are reviewed. Fiber length and angulation in the complex M. adductor mandibulae externus 2 of a lizard were measured stereotactically; these values correlace well with the hypothesis that the muscle shows equivalence and demonstrate that angulation for pinnation is less constant. An outline for the study of muscle architecture and function, detailing the kinds of information required to estimate forces and evaluate muscle and fiber placements, is presented.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920106
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  • 83
    Digitale Medien
    Digitale Medien
    Ultrastructural and quantitative dynamics of the granulosa of ovarian follicles of the lizard gerrhonotus coeruleus (family anguidae) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 125-144 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The progression of ovarian follicular development in the Northern Alligator Lizard has been documented ultrastructurally and by enumeration of cells, with a focus on changes in the granulosa component of the follicle. The pattern of cellular differentiation of the granulosa entails, as in other lizards, the transformation of a simple, cuboidal epithelium in small follicles into a complex layer consisting of three types of cells. Marked differences in size and ultrastructure of the cell types indicate different functional states: the smallest cells are little differentiated and serve primarily as stem cells to other granulosa cells throughout follicular growth, whereas the larger “intermediate” and “pyriform” cells do not divide and show ultrastructural features indicative of synthetic activity. Contrary to some views that this latter cell type is the final step in cellular differentiation and provides organelles and cytoplasm to the oocyte through an intercellular bridge, the results of this study suggest that only relatively small molecules such as ribosomal RNA might pass between cells. Further, these observations support the interpretation that a heterogeneous granulosa results from the fusion in early follicular stages of some cells that are in surface contact with the oocyte. Several of the cytological features of the larger granulosa cell types are seen in the oocyte and in germ-line cells generally, such as highly dispersed chromatin, large nucleoli, abundant nuclear pores, mitochondrial “rosettes,” annulate lamellae, “ribosome bodies,” and surface microvilli. This strongly suggests that the cytology of large granulosa cells is induced by the oocyte. The heterogeneous granulosa persists only through previtellogenesis and at the onset of exogenous yolk uptake by the oocyte it becomes a secondarily homogeneous layer. The appearance of the granulosa at this stage is similar to that of reptiles whose granulosa remains a single-cell layer throughout folliculogenesis (e.g., turtles and crocodilians). Thus, although follicular development has been scrutinized in only a few representative genera of reptiles to date, the course of follicular development among lizards is similar in detail and involves the transitory development of a heterogeneous population of cells. This feature appears to be exclusive to the squamate reptiles.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920205
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  • 84
    Digitale Medien
    Digitale Medien
    Masthead (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920301
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  • 85
    Digitale Medien
    Digitale Medien
    Collateral projections from trigeminal sensory nuclei to ventrobasal thalamus and cerebellar cortex in rats (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 229-236 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The retrograde fluorescent labeling technique reveals that trigeminal projections to the ventroposteromedial nucleus of the thalamus (VPM) of the rat originate from the main sensory nucleus (MSN) of the trigeminal and subnuclei interpolaris (V1) and caudalis (Vc) of the spinal trigeminal nucleus. These projections are predominately contralateral; however, the presence of a few ipsilateral labeled cells in MSN suggests an uncrossed trigeminothalamic pathway. Trigeminocerebellar fibers projecting to the paramedian lobule (PML) of the cerebellar cortex are located in Vi and caudal subnucleus oralis (V0). This is principally an ipsilateral pathway, but several bisbenzimide-labeled cells are present in contralateral Vi. The most notable finding occurred after paired injections of Evans Blue into VPM and bisbenzimide into PML, demonstrating neurons in Vi with divergent projections to both structures. The presence of this type of projection was not found in mice (Steindler: J. Comp. Neurol. 237:155-175, 1985) and has not been reported in other species.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051920305
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  • 86
    Digitale Medien
    Digitale Medien
    The spermatophore and its structural changes with time in the bursa copulatrix of the silkworm, Bombyx mori (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 1-11 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The bursa copulatrix of the silkmoth is filled with various secretions and seminal fluid transferred from the male reproductive system during mating. The contents of the bursa include a pearly body, spermatophragma, and spermatophore. The latter consists of a four-layered wall, an inner and outer matrix, and a soft plug. The components of the spermatophore are all heterogeneous, since they are formed by the partially mixed, viscous streams of the male secretions. Apyrene spermatozoa and eupyrene bundles are present only in the inner matrix, but both the matrices are important sites of sperm maturation. After spermatophore formation, the basophilic regions and periodic acid-Schiff (PAS)-granules in both matrices gradually decrease with time. The PAS-granules were identified as glycogen by α-amylase treatment. The inner matrix containing sperm and the outer matrix decrease in volume and become concentrated near the neck of the spermatophore. Apyrene and eupyrene spermatozoa can move toward the ductus seminalis after their maturation. A large, beltlike space which does not stain remains at the periphery of the spermatophore. These structural changes of spermatophore contents seem to reflect metabolic reactions in the spermatophore as the reactor for sperm maturation.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930102
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  • 87
    Digitale Medien
    Digitale Medien
    Evocation of venation pattern in the wing of a moth, Manduca sexta (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 53-62 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The insect wing is formed from an epithelial sheet that folds during development to establish a saclike tissue with an upper and a lower epithelial monolayer. The adult cuticle formed by the upper and lower monolayers has a distinctive pattern of thickened regions called veins. The venation pattern on the lower surface matches that on the upper surface. As demonstrated by transposition of grafts from the upper monolayer, determination of venation pattern occurs prior to pupation in both wing monolayers. However, the pattern is not expressed until later in adult development. Expression of this determined pattern occurs autonomously in most circumstances. One circumstance in which the pattern fails to be expressed is in pieces of the upper monolayer that are isolated from the lower monolayer before adult cuticle deposition and expression of venation pattern. The only evident interaction between the two monolayers of the wing occurs during a 3-day period, 6-8 days after pupation. During this time, the basal laminae segregating upper monolayer from lower monolayer disappear, and the basal ends of cells form desmosomal junctions at the interface between upper and lower monolayer. Transposition as well as isolation of tissue fragments from the upper monolayer suggest that this interaction between the basal surfaces of the two monolayers is a prerequisite for evocation of venation pattern.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930106
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  • 88
    Digitale Medien
    Digitale Medien
    Masthead (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930201
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  • 89
    Digitale Medien
    Digitale Medien
    Antennal sensory organs in the millipede Eurypauropus ornatus: Fine structure of the flagella and globulus (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 159-171 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: On the antennal tip of Eurypauropus ornatus are 3 threadlike sensilla - the flagella, and a single spheroid sensillum - the globulus. Each of the 3 flagella is innervated by 2 groups of sensory cells. One group contains 4 cells, the other, 5. All cells of the “four group” and 3 of the “five group” are comprised of single cilia and unbranched dendrites which extend along the lumen of the flagellum. Two cells of the “five group” have double cilia and pairs of unbranched dendrites. One pair also enters the flagellum and the other pair terminates beneath the flagellar base to form a concentric array of lamellae. No pores are present in the cuticular wall.Eight sensory cells innervate the globulus. They are arranged in 3 groups, one triplet and 2 pairs, in addition to a single cell. The single cell contains a pair of cilia whose unbranched dendrites differentiate into tubular bodies that are inserted into the base of the globulus. Each of the other 7 sensory cells has a single cilium. Their unbranched dendrites penetrate into the globulus in 3 groups as described for the sensory cells. The dendrites in each group terminate in an individual pore channel at the globulus tip and completely fuse with the electron-dense material that plugs the pore channel.Based on structural similarities to sensilla having known functions, it is probable that the flagella and the globulus are chemoreceptors, the former responding to odors, the latter sensitive to substances in aqueous solution.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930204
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  • 90
    Digitale Medien
    Digitale Medien
    Masthead (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930301
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  • 91
    Digitale Medien
    Digitale Medien
    100 years! (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 219-220 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051940302
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  • 92
    Digitale Medien
    Digitale Medien
    Fine structure and absorption of ferritin in the digestive organs of Loligo vulgaris and L. Forbesi (Cephalopoda, Teuthoidea) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 173-184 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The digestive organs possibly involved in food absorption in Loligo vulgaris and L. forbesi are the caecum, the intestine, the digestive gland, and the digestive duct appendages. The histology and the fine structure showed that the ciliated organ, the caecal sac, and the intestine are lined with a ciliated epithelium. The ciliary rootlets are particularly well developed in the ciliated organ, apparently in relation to its function of particle collection. Mucous cells are present in the ciliated organ and the intestine. Histologically, the digestive gland appears rather different from that of other cephalopods. However, the fine structure of individual types of squid digestive cell is actually similar to that of comparable organs in other species, and the squid cells undergo the same stages of activity. Digestive cells have a brush border of microvilli, and numerous vacuoles, which sometimes contain “brown bodies.” However, no “boules” (conspicuous protein inclusions of digestive cells in other species) could be identified in their cytoplasm; instead only secretory granules are present. In the digestive duct appendages, numerous membrane infoldings associated with mitochondria are characteristic features of the epithelial cells in all cephalopods. Two unusual features were observed in Loligo: first, the large size of the lipid inclusions in the digestive gland, in the caecal sac, and in the digestive duct appendages; and second, the large number of conspicuous mitochondria with well-developed tubular cristae. When injected into the caecal sac, ferritin molecules can reach the digestive gland and the digestive duct appendages via the digestive ducts, and they are taken up by endocytosis in the digestive cells. Thus, it appears that the digestive gland of Loligo can act as an absorptive organ as it does in other cephalopods.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930205
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  • 93
    Digitale Medien
    Digitale Medien
    Viviparous development in Botrylloides (Compound Ascidians) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 193 (1987), S. 263-276 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The mode of sexual reproduction and embryogenesis was compared in 3 species of Botrylloides: B. simodensis, B. lenis, and B. violaceus. In all species, a testis and an egg (occasionally 2 eggs), the former being anterior to the latter, mature in the mantle on either side of a zooid. The egg is surrounded by 2 follicular layers and is attached by a vesicular follicle stalk (oviduct) to the atrial brood pouch. The egg is ovulated into the brood pouch, where it is fertilized and undergoes embryogenesis. The egg of B. simodensis is heavily yolked and measures about 180 μm in diameter. The course of embryogenesis in this species is that typical of ascidians. A mature tadpole larva is produced and shed in about 5 days; then, the mother zooid degenerates. The larva is smallest of the three species and has 8 ampullae. The metamorphosed oozooid bears a single bud on the right side only. Extraembryonic nutrition seems to be very limited.Both Botrylloides lenis and B. violaceus are species which display extreme examples of viviparity. Their eggs are devoid of yolk granules, measuring about 90 μm in diameter in the former species and 60 μm in the latter. The course of embryogenesis is similar in these 2 species. The neurula stage is characterized by a spherical vesicular shape owing to precocious differentiation of the embryonic pharynx, whose ectoderm becomes vacuolated. At the posterior end of the neurula, the mesodermal cells are located in a mass, from which the tail is extended later. In B. lenis, embryogenesis takes about 20 days. At the neurula stage of the embryo, the mother zooid becomes a mantle sac as a result of visceral disintegration. During further embryogenesis, the growth of buds of successive generations in the colony is characteristically arrested. A swimming larva of this species is somewhat larger than that of B. simodensis. It has 14-24 ampullae, and the oozooid carries a single bud on its right side. In B. violaceus, the gestation period lasts for more than a month. At the early gastrula stage of the embryo, the body of the mother zooid fully disintegrates. Only the brood pouch bearing the embryo survives and remains connected with the colonial vascular system. In this species, sexual reproduction does not affect the growth of buds in the colony. The swimming larva is gigantic, being furnished with 24-34 ampullae, and the oozooid always bears 3 buds, 2 on the right side and one on the left side.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051930305
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  • 94
    Digitale Medien
    Digitale Medien
    Anterior dorsal ventricular ridge in the lizard: Embryonic development (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 55-64 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In lacertids the telencephalic vesicle starts its development at stage E = 30, at which time it is lined by a homogeneous nucleated zone in which particular ventricular zone territories or sulci cannot be distinguished. At stage E = 32 coinciding with the initial development of the anterior dorsal ventricular ridge (ADVR), one may distinguish the ventricular zone b in the dorsolateral wall of the ventricle adjacent to the sulcus lateralis. The ADVR continues growing by incorporation of cells produced in two proliferative zones (zone b and wall of the sulcus lateralis) and appears fully developed in postnatal lizards. Ultrastructural characteristics of young ADVR neurons between stages E-32 and E-33 are typical of those in immature cells. Beginning at stage E-34, some of these neurons appear to be degenerating (pycnotic). Thereafter, neurons of the ADVR develop abundant cytoplasmic organelles and the neuropile grows quickly. Myelination starts in the ADVR between stages E-38 and E-40, but is not observed in other striatal masses in the same period. Vascularization begins and is well developed at E-40. The first synaptic contacts were observed in embryos of stage E=38; they are chiefly axo-dendritic, although some are axo-somatic. Degenerating neurons were found in the ADVR up to hatching. From stage E-40 onward, the ADVR shows a greater and more rapid differentiation than all other striatal nuclei, including the ventral and amygdaloid complex.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051940105
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  • 95
    Digitale Medien
    Digitale Medien
    Model of jaw depression during feeding in Astatotilapia elegans (Teleostei: Cichlidae): Mechanisms for energy storage and triggering (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 85-109 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Suction feeding in Astatotilapia elegans occurs by a series of rapid, coupled movements of various head parts. The lower jaw rotates with respect to the neurocranium through an angle of 62° in less than 15 ms. The power requirements for jaw depression are calculated from a mathematical model and may reach a peak of ±4 watt in a 12-cm-long specimen. Data from the literature on mechanical output of fish muscle suggest that a muscular volume equal to 44% of the volume of the fish (= 45 cm3) should be required, if it is premised that movement and muscle shortening are directly coupled. Therefore, we assumed that storage and release of strain energy must be considered. The work demands for depression equal 0.014 J. The amount of energy storable in only three pairs of head ligaments can be estimated between 0.008 J and 0.05 J. The use of strain energy implies initial blocking and subsequent triggering of the movement. The position of the hyalomandibular connection, dorsal to the mandibular-suspensorial articulation, appears to be of crucial importance in balancing the forces of sternohyoideus and the body muscles. Triggering at the onset of jaw depression occurs by the contraction of the levator operculi. The line of action of the hyalomandibular connection is lowered beneath the jaw suspension, which raises the equilibrium of forces. Elastic recoil can occur thereafter.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051940108
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  • 96
    Digitale Medien
    Digitale Medien
    Location of the rostral end of the longitudinal brain axis: Review of an old topic in the light of marking experiments on the closing rostral neuropore (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 163-171 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The rostral end of the forebrain was classically defined on the basis of descriptive data. Different assumptions on the mode of closure of the rostral neuropore caused three different theories of the rostral end of the forebrain to be formulated (His 1893a; von Kupffer, '06; Johnston, '09). Some recent descriptive and experimental data have put these theories into question.A piece of black nylon thread was inserted through the rostral neuropore of chick embryos and was fixed to its ventral lip. These operations were done at all intermediate stages during the process of closure of the rostral neuropore. The embryos were sacrificed at a later stage, by which time the neuropore had disappeared.In the cleared specimens the threads always lay at the same site, namely the upper border of lamina terminalis, irrespective of the stage at which the marker was inserted. These results stand against His's conception ((1893a, b) of a sutura terminalis and support the single mechanism of sutura dorsalis during closure of the rostral neuropore. The marking data therefore imply that the topologic rostral end of the forebrain lies at the upper limit of lamina terminalis, as proposed by von Kupffer, '06).
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051940205
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  • 97
    Digitale Medien
    Digitale Medien
    Development of the glycogen body of the Japanese quail, Coturnix Japonica. I. Light microscopy of early development (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 209-217 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The glycogen body is a functionally enigmatic structure located in lumbosacral region of the spinal cord in birds. This tissue is unique to birds, and, although it is believed to be present in all species, studies on the glycogen body to date have been confined largely to the domestic chicken. The present study is the first to describe the glycogen body of the Japanese quail (Coturnix japonica) during incubation and at hatching. Light microscopy and histochemistry were used to identify the glycogen body in the spinal cord of the developing quail beginning at 7 days of incubation and to ascertain the presence of nerve fibers in that tissue at hatching.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051940209
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  • 98
    Digitale Medien
    Digitale Medien
    A morphological study of the anterior nervous system of the praesoma of Neoechinorhynchus cylindratus (Acanthocephala: Neoechinorhynchidae) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 235-245 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The nerve pathways in the praesoma, based on light microscopy of serial transverse, sagittal, and longitudinal sections stained with Ehrlich's acid hematoxylin are described for the first time for a memeber of Neoechinorhynchus. The route from the cerebral ganglion to the musculature and sense organs of the proboscis and body wall for 11 nerves, five pair and one single, the presence and structure of the Stutzzelle (support cell) and its association with the neck sense organs are described. A comparison with the nervous system in the praesoma of Paulisentis fractus is discussed.
    Zusätzliches Material: 19 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051940304
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  • 99
    Digitale Medien
    Digitale Medien
    Seasonal changes in the oviduct of the pied myna (Aves: Sturnidae) (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 247-263 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Study of the oviduct of the pied myna (Sturnus contra contra) throughout the year reveals that oviducal weight, length, surface epithelial height and glycogen content are low during August to January (nonbreeding phase), partially increase during February to April (prebreeding phase), maximally increase in May (breeding phase) and decrease in June and July (post-breeding phase). In the nesting cycle, there is greatest growth in all the regions of the oviduct from early nest-building to the egg-laying period and this is followed by rapid involution during incubation and nestling periods.Some notable features in the oviduct of the pied myna are described: (1) All five regions of the oviduct (infundibulum, magnum, isthmus, uterus, and vagina) are clearly distinguishable when studied from serial sections of the oviduct even during the nonbreeding phase of the annual ovarian cycle. (2) There is a strong correlation between initiation of tubular gland formation and the onset of nestbuilding activity. (3) The distal part of the magnum is differentiated into a ‘mucous region’ having well developed basal nonciliated cells. (4) A sixth zone can be identified between the magnum and isthmus. Sperm hostlike glands exist at the cranial end of the zone. (5) Several circular epithelial invaginations are evident in the intermucosal folds and their size decreases in centripetal order in the vagina. (6) The pattern and degree of regression are different in various regions of the oviduct.A close synchrony between ovarian and oviducal cycles is indicated in the pied myna (Sturnus contra contra).
    Zusätzliches Material: 22 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051940305
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  • 100
    Digitale Medien
    Digitale Medien
    A golgi study of the dorsal cortex in the lizard Psammodromus algirus (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 265-274 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The dorsal cortex of Psammodromus algirus is three-layered. From the pia to the ependyma, it consists of a superficial plexiform layer, a cellular layer, and a deep plexiform layer. Five neuronal types have been classified in the dorsal cortex. Pyramidal neurons represent 18.75% of neurons and differ morphologically depending on their position in the pars medialis or lateralis of dorsal cortex. Pyramidal neurons in the pars medialis are smaller and their apical dendritic fields are less extensive than those of pyramidal neurons in the pars lateralis. Bitufted neurons represent 22.5% of dorsal cortical neurons and are only found in the cellular layer of the pars lateralis. Multipolar neurons are distributed in the pars medialis and lateralis, in the cellular layer and the deep plexiform layer; they represent 46.25% of the total impregnated cells. Bipolar neurons are found mainly in the deep plexiform layer and form 11.25% of neurons. Two subtypes may be distinguished: horizontal and vertical bipolar cells. Juxtaependymal neurons represnt 1.25% and are located just above the ependyma. All the neurons in the cellular layer are projection cells.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051940306
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