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  • 1980-1984  (122)
  • 1915-1919
  • 1850-1859
  • 1830-1839
  • 1980  (122)
  • 1918
  • Ultrastructure  (122)
  • 101
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 207 (1980), S. 499-509 
    ISSN: 1432-0878
    Schlagwort(e): Mast cells ; Granulocytes ; Lymphoid cells ; Ultrastructure ; Cloaca ; Domestic fowl
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Motile cells (mast cells, granulocytes, lymphoid cells) are described in the mucosa of the cloacal urodaeum and proctodaeum of the female domestic fowl. Diffuse lymphoid tissue with lymphatic nodules occurs in the urodaeum at the ureteral ostium. Small local aggregations of lymphoid tissue can be observed in the mucosa of the proctodaeum. Cells originating from these sites penetrate the basal lamina of the epithelium and are then found between the epithelial cells. In the subepithelial layers the motile cells sometimes are in contact with each other. Mast cells (tissue basophils) form contact zones, resembling desmosomes or half desmosomes, with smooth muscle cells. In the mast cells three types of granules can be distinguished. Their ultrastructure is discussed in comparison with that in similar cells of the guinea pig.
    Materialart: Digitale Medien
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  • 102
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 208 (1980), S. 85-98 
    ISSN: 1432-0878
    Schlagwort(e): Pars intermedia ; Stellate cell ; Macrophage ; Ultrastructure ; Phagocytosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In an attempt to study further the stellate cell and its functions, the ultrastructure of this cell type in the neurointermediate lobe of the bullfrog, Rana catesbeiana, was examined in both organ and dissociated-cell culture. The cytoplasmic activity of stellate cells from neurointermediate lobes incubated 3 1/2 or 5 1/2 h was greater than that of those in vivo. Mitochondria and bundles of cytoplasmic filaments were numerous, in addition to prominent, well-developed Golgi complexes with associated vesicles. The most striking ultrastructural feature was the presence of phagocytic vacuoles that contain cellular debris. The stellate cells were seen to form cytoplasmic processes that phagocytosed this extracellular debris identifiable as belonging to the secretory cells of the pars intermedia. The stellate cells from the dissociated-cell preparations were also seen to contain debris within phagocytic vacuoles. In those neurointermediate lobes transplanted for 3 1/2 to 4 days into the anterior chamber of the eye, the stellate cells demonstrated similar phagocytic ability, but the phagocytic vacuoles contained material that seemed to be at a later stage of degradation. In all three of these conditions, the stellate cells were not seen to release this cellular debris nor were they seen to undergo cell division. These glial-like stellate cells of the pars intermedia acted as macrophages in all three of these experiments. There is now, therefore, a need to determine under what conditions, if any, these stellate cells function in vivo as macrophages.
    Materialart: Digitale Medien
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  • 103
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 208 (1980), S. 197-206 
    ISSN: 1432-0878
    Schlagwort(e): Glycogen ; Degeneration ; Ascidian ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Degeneration is observed in cells of the pyloric gland of Dendrodoa grossularia in which glycogen storage occurs. The ultrastructure of four phases of the degeneration cycle is described. Natural senescence seems to be the cause of the degeneration. Glycogen storage might be the result of metabolic disturbance, but its presence reveals the importance of glycogen in the function of the organ. The role of the pyloric gland is discussed.
    Materialart: Digitale Medien
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  • 104
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 208 (1980), S. 247-252 
    ISSN: 1432-0878
    Schlagwort(e): Pineal gland ; Cold ; Ultrastructure ; β-receptor ; Mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Quantitative electron microscopic studies on the mouse pineal gland were done to elucidate the mechanism of the response of the granulated vesicles in pinealocytes to acute cold exposure. An increase in the number of the granulated vesicles in the mouse pinealocytes occurs following administration of isoproterenol and this increase is prevented by pretreatment with the βadrenergic blocking agent, propranolol. In addition, a numerical increase of the granulated vesicles in response to acute cold exposure is abolished in mice pretreated with propranolol or in adrenalectomized animals. The results suggest that catecholamines released from the adrenal medulla, but not from sympathetic nerve endings, may cause the response of the granulated vesicles to cold by way of β-receptors.
    Materialart: Digitale Medien
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  • 105
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 208 (1980), S. 371-387 
    ISSN: 1432-0878
    Schlagwort(e): Lobula complex ; Visual interneurons ; Ultrastructure ; Cobalt-impregnations ; Electron microscopy ; Diptera (Calliphora erythrocephala)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The synaptic organization of three classes of cobalt-filled and silver-intensified visual interneurons in the lobula complex of the blowfly Calliphora (Col A cells, horizontal cells and vertical cells) was studied electron microscopically. The Col A cells are regularly spaced, columnar, small field neurons of the lobula, which constitute a plexus of arborizations at the posterior surface of the neuropil and the axons of which terminate in the ventrolateral protocerebrum. They show postsynaptic specializations in the distal layer of their lobula-arborizations and additional presynaptic sites in a more proximal layer; their axon terminals are presynaptic to large descending neurons projecting into the thoracic ganglion. The horizontal and vertical cells are giant tangential neurons, the arborizations of which cover the anterior and posterior surface of the lobula plate, respectively, and which terminate in the perioesophageal region of the protocerebrum. Both classes of these giant neurons were found to be postsynaptic in the lobula plate and pre- and postsynaptic at their axon terminals and axon collaterals. The significance of these findings with respect to the functional properties of the neurons investigated is discussed.
    Materialart: Digitale Medien
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  • 106
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 208 (1980), S. 507-510 
    ISSN: 1432-0878
    Schlagwort(e): Pancreatic B-cell ; Tubuloampullar structures ; Rough endoplasmic reticulum ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Unusual aggregations of ampullar dilated tubules (tubuloampullar structures, TAS) were observed in pancreatic B-cells of rats and in one case of human malignant insulinoma. The TAS were invariably associated with dilated rough endoplasmic reticulum, but lacked ribosomes. They were frequently seen to be closely associated with the Golgi apparatus. Furthermore, TAS were located mainly in degranulated areas of B-cells.
    Materialart: Digitale Medien
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  • 107
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 209 (1980), S. 187-200 
    ISSN: 1432-0878
    Schlagwort(e): Pineal organ ; Teleostei ; Syngnathidae ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A comparative ultrastructural study was made of the pineal organ of two related species of the Syngnathidae, the pipefish, Syngnathus acus, and the seahorse, Hippocampus hudsonius. Both species have a relatively small pineal organ, which ultrastructurally shows several similarities with the pineal of other teleosts. In the pineal organ of Syngnathus acus, the photoreceptor cells have well-developed outer segments consisting of about 15 to 60 saccules. The pineal supporting cells are characterized by the presence of numerous myeloid bodies. In Hippocampus hudsonius the pineal outer segments are scarce and poorly developed; generally, they show not more than 20 saccules. The apical parts of the supporting cells contain dense-core vesicles with a diameter varying from 100 to 180 nm. Corresponding vesicles were not observed in the pineal organ of Syngnathus acus. Arguments are presented for the suggestion that the pineal organ of the Syngnathidae, in spite of its relatively small size, still has a functional significance. In Syngnathus acus, light reaching the pineal organ directly might have a regulating effect on pineal activity. In Hippocampus hudsonius, however, light acting directly on the pineal organ appears to have minor effect on pineal function.
    Materialart: Digitale Medien
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  • 108
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 209 (1980), S. 329-343 
    ISSN: 1432-0878
    Schlagwort(e): Stomach ; Innervation ; Myenteric plexus ; Guinea-pig ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the vesicle-containing axon profiles in the myenteric ganglia of the guinea-pig stomach was studied in specimens fixed by vascular perfusion and in specimens fixed by immersion in cold fixative after incubation in 5-hydroxydopamine. Three major types of vesicle-containing axon profile were identified in the ganglia: 1. Profiles containing numerous small, mainly spherical vesicles and only limited numbers of large dense-cored vesicles. In perfusion-fixed specimens, the small vesicles in these profiles were all clear. In specimens fixed by immersion after incubation in 5-hydroxydopamine, the profiles could be divided into three types: a) profiles containing small clear vesicles; b) profiles containing small dense-cored vesicles; c) profiles in which the small vesicles contained a peripheral rim of dense material. In these profiles, large vesicles which contained dense cores were rare. The mean diameter of the vesicles in the profiles was also significantly higher than in the profiles containing small clear vesicles. 5. Profiles containing flattened membrane-bounded structures. Reconstructions prepared from serial sections suggested that these structures represented sections through networks of smooth endoplasmic reticulum-like tubules rather than flattened vesicles. 6. Profiles containing many large dense-cored vesicles and few small clear vesicles. In perfusion-fixed specimens, the diameter of the dense-cored vesicles in these profiles was significantly higher than in the type 1 profiles. Type 1 a and type 1 c profiles were much more numerous than either type 2 or type 3 profiles, and type 1 b profiles were few. Synaptic junctions were found in association only with type 1 a profiles. Type 1 a and type 1 b profiles resembled cholinergic and adrenergic axon terminals. The remaining profiles may represent the terminals of different forms of peptidergic axon or of other as yet unidentified types of axon.
    Materialart: Digitale Medien
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  • 109
    ISSN: 1432-0878
    Schlagwort(e): Carbonic anhydrase ; Ultrastructure ; Shell formation ; Ionic regulation ; Lymnaea stagnalis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructural localization of carbonic anhydrase (CA) was investigated with the cobalt-bicarbonate method in three epithelia of the pond snail Lymnaea stagnalis. In the epidermis a selective population of “positive cells” was observed. In these cells, CA is confined to the apical and to small parts of the lateral plasma membrane. In cells of the outer mantle epithelium, CA is localized in the lateral and basal parts of the plasma membrane. In cells of the ureter, CA was found apically as well as basally. The localization of CA is discussed in relation to the different functions of the epidermis (electrolyte uptake), mantle (HCO 3 − secretion, calcification) and ureter (electrolyte uptake, acid-base regulation).
    Materialart: Digitale Medien
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  • 110
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 210 (1980), S. 21-32 
    ISSN: 1432-0878
    Schlagwort(e): Eyespots ; Photoreceptor ; Chemoreceptor ; Turbellaria ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The eyespots of Microstomum lineare were studied by electron microscopy, light microscopy, and fluorescence microscopy. Each eyespot consists of two ciliary photoreceptor cells shielded by pigment cells and additional sensory cells. The photoreceptor cells are characterized by a distal intracellular cavity lined with 50–100 interwoven cilia. The other sensory cells are of two ultrastructurally different types, one with long cilia predominating and the other with balloonlike cilia. The pigment cells, which envelop processes of the sensory cells, contain pigment vacuoles varying in size and content and give a bright red fluorescence by the Falck-Hillarp method. The eyespots are suggested to perform a dual function as photoreceptors and chemoreceptors. The evolutionary significance of ciliary photoreceptors in Turbellaria is discussed.
    Materialart: Digitale Medien
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  • 111
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 210 (1980), S. 95-100 
    ISSN: 1432-0878
    Schlagwort(e): Myocardial cells ; Ultrastructure ; Differentiation ; T-tubule formation ; Opossum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Cardiac muscle cells in the right ventricle of the postnatal opposum were studied ultrastructurally, with particular attention to the developmental stage of T-tubule formation. Animals ranging from 5.5cm (day 29 of postnatal life) to 41 cm (young adult) in body length were used. Typical T-tubules were first recognized in a few myocardial cells of the 7.5cm (day 43) opossum. T-tubules increased in number as cardiac muscle cells continued to differentiate until 22cm in body length (about 105 days after birth). At this stage of development most of the T-tubules were completely established. The general mode of differentiation and development of cardiac muscle cells appeared essentially the same as in other mammals.
    Materialart: Digitale Medien
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  • 112
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 210 (1980), S. 155-165 
    ISSN: 1432-0878
    Schlagwort(e): Sympathetic ganglion ; Teleost ; Ultrastructure ; Histochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In order to compare the structure of a teleost sympathetic ganglion with those of other vertebrates, light, fluorescence histochemical and electron microscopy were carried out on the coeliac ganglion of the scorpion fish, Myoxocephalus scorpius. In common with studies on other vertebrates, fluorescence histochemistry distinguished two cell types: a) principal neurones which exhibited low levels of specific catecholamine fluorescence and comprise the majority of neurones in the ganglia, and b) smaller intensely fluorescent cells, some of which had processes tens of micrometers long. With the electron microscope, the principal cells were seen to make axodendritic and axosomatic synapses with axons containing mainly 30 nm agranular vesicles at the synaptic site while in other vertebrates usually only one or other synaptic association is present. Both the somata and the processes of intensely fluorescent cells contain 300–600 nm diameter vesicles many of which have electron dense cores. These cells are also innervated by axons containing 30 nm agranular vesicles.
    Materialart: Digitale Medien
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  • 113
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 210 (1980), S. 249-256 
    ISSN: 1432-0878
    Schlagwort(e): Synaptic ribbons ; Pineal organ ; Goldfish ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Synaptic ribbons in the pineal organ of the goldfish were examined electron microscopically with particular attention to their topography. These structures were formed of parallel membranes, which were poorly preserved with OsO4 fixation and could be extracted from thin sections with pronase indicating their proteinaceous nature. Synaptic ribbons were closely apposed to the plasma membrane bordering dendrites of ganglion cells, but were also related to processes of both photoreceptor and supportive cells. Their close proximity to invaginations of the plasma membrane and portions of the endoplasmic reticulum suggest that they are involved in the turnover of cytoplasmic membranes. Tubular and spherical organelles of unknown function are also described.
    Materialart: Digitale Medien
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  • 114
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 210 (1980), S. 359-369 
    ISSN: 1432-0878
    Schlagwort(e): Epidermis ; Acidophilic cell ; Histochemistry ; Ultrastructure ; Salmo trutta L
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Acidophilic cells occur in the epidermis of several species of salmonid fish, although their abundance fluctuates considerably between individuals within the same population and at different times during the life cycle. The histology, histochemistry and ultrastructure of an acidophilic, granular celltype in the epidermis of the brown trout, Salmo trutta L., is described. At the light microscope level this cell type is easily distinguished from the large, mucus-secreting, epidermal goblet cells by its acidophilic, proteinaceous secretion. At the ultrastructural level this secretion consists of membrane-bound granules formed by the very active Golgi region. It is argued that the acidophilic, granular cell is not a transformed blood cell but constitutes a normal epidermal component of the brown trout. Possible roles of this cell in the function(s) of the epidermis are discussed.
    Materialart: Digitale Medien
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  • 115
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 210 (1980), S. 435-445 
    ISSN: 1432-0878
    Schlagwort(e): Ultrastructure ; Mechanoreceptor ; Skin ; Reptile
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The histological and ultrastructural organisation of the epidermal sensory organs in Amphibolurus barbatus has been described with respect to their position and possible functions. The sensory organs, located at the scale's edge, are most numerous in scales of the dorsal surface of the head. Most other scales of the body surface have two receptors located laterally to the spine or keel of the scale. In the imbricate scales of the ventral body region, the receptors lie just beneath the reinforced scale lip. Scanning electron microscopy has revealed the surface of the organ to be a crater lacking any surface projections. These sensory organs have a dermal papilla consisting of a nerve plexus and loose connective tissue. The nerve fibres arising from the plexus, pass to the epidermal columnar cells, where some form nerve terminals at the base of the cells, while others pass between them to form nerve terminals embedded in a superficial layer of cuboidal cells. The superficial terminals are held against the overlying α keratin by masses of tonofilaments. The β keratin is thickened to form a collar around the periphery of the organ but is only about 0.5 μm thick immediately above it. Mechanical deformation of the scale's spine or reinforced scale lip may initiate stimulation of the nerve terminals described.
    Materialart: Digitale Medien
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  • 116
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 211 (1980), S. 31-40 
    ISSN: 1432-0878
    Schlagwort(e): Nervous system ; Turbellaria ; Fluorescence histochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The nervous system (NS) of Microstomum lineare (Turbellaria, Macrostomida) was studied by electron and light microscopy, combined with fluorescence histochemistry (Falck-Hillarp method for biogenic monoamines). The NS is primitively organized, with a bilobed brain, two lateral nerve cords lacking commissures, and peripheral nerve cells scattered along the nerve cords. The stomatogastric NS, with a pharyngeal nerve ring, is joined to the central NS by a pair of connective ganglia. A green fluorescence in all parts of the NS indicates catecholaminergic neurons as the dominant neuron type. Ultrastructurally, two types of neurons were identified on the basis of their vesicle content: 1. Aminergic (catecholaminergic) neurons containing densecore vesicles of varying electron-density and size, i.e., small dense-core vesicles (diameter 50–100 nm), vesicles with a highly electron-dense core (60–140 nm), and vesicles with an eccentric dense-core. 2. Presumed peptidergic neuro-secretory neurons containing large granular vesicles (diameter about 200 nm) in the stomatogastric NS and peripheral parts of the central NS. In light microscopy, paraldehyde-thionin stained neurons were observed in the same areas.
    Materialart: Digitale Medien
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  • 117
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 211 (1980), S. 151-161 
    ISSN: 1432-0878
    Schlagwort(e): Pinealocytes ; Pig ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Pinealocytes of female pigs were studied electron-microscopically and compared with those of other mammals. A prominent Golgi apparatus forming dense-cored vesicles was widely dispersed in the cytoplasm of the cell body. A very characteristic feature of the pig pinealocytes was the presence of membrane-bounded bodies showing wide variations in internal structure. Possible roles of the dense-cored vesicles and membrane-bounded bodies in secretory processes of pinealocytes are discussed.
    Materialart: Digitale Medien
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  • 118
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 211 (1980), S. 391-403 
    ISSN: 1432-0878
    Schlagwort(e): Ocelli ; Dinopid spider ; Ultrastructure ; Optics ; Evolution of nocturnal eye
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The posterior median (pm) eyes of the dinopid spider Menneus unifasciatus L. Koch are described and compared with the pm eyes of Dinopis, which are highly specialised for night vision. The lenses of Menneus have F-numbers of 0.72 compared to 0.58 in Dinopis, the distance between receptors is ca. 4.0 μm compared to 20–22 μm for Dinopis, and image quality is matched to receptor spacing. The lens of Menneus is simple, while that of Dinopis comprises two components of different refractive indices (Blest and Land 1977). Receptive segments of the pm eyes of Dinopis are hexagonal in transverse section and those of adjacent cells are tightly contiguous, allowing the possibility of both optical and electrical coupling (Blest 1978). Receptive segments of Menneus are separated from each other by glial processes containing little pigment, and each segment possesses two rhabdomeres on opposite faces of the cell. Rhabdomere volumes undergo a daily cycle similar to that described for Dinopis, but of relatively minor extent. It is shown that the pm eye of Dinopis could have evolved from that of Menneus by a simple series of transformations, and that a gain of two logarithmic units of sensitivity can be attributed to changes in optical design alone.
    Materialart: Digitale Medien
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  • 119
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 211 (1980), S. 449-463 
    ISSN: 1432-0878
    Schlagwort(e): Ependyma ; Choroid plexus ; Leptomeninges ; Ultrastructure ; Bullfrog ; Tela choroidea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The lateral areas of the rhombencephalic tela of the bullfrog contain long, irregular islands of ependymal cells that are similar in fine structure to the epithelium of the rhombencephalic choroid plexus. These cells are characterized by apical microvilli, numerous mitochondria and pinocytotic vesicles, and basal infoldings of the plasma membrane. Dorsally a basal lamina and varying amounts of collagen occur. The pia mater associated with this ependyma includes two cell types. Fibroblast-like, loosely arranged cells without organized junctions line the subarachnoid space. The most abundant cells of the pia in this area, however, contain numerous intermediate filaments and frequent desmosomes. Caveolae lie along their plasma membranes. Closely organized sheets of similar filament-containing cells are also seen in the arachnoid mater of this animal. These findings demonstrate ependymal cells in the lateral areas of the rhombencephalic tela of the bullfrog that have the essential features of choroid plexus epithelium, with ultrastructural characteristics that suggest transport function. They are, however, usually separated from neighboring, nonfenestrated vessels by several layers of leptomeningeal cells joined by desmosomes. The relationship between structure and function of these cells is enigmatic.
    Materialart: Digitale Medien
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  • 120
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 212 (1980), S. 475-495 
    ISSN: 1432-0878
    Schlagwort(e): Distal tubule ; Connecting tubule ; Collecting duct ; Ultrastructure ; Desert rodent (Psammomys obesus)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The transition from the nephron to the collecting duct is formed by three tubular segments (convoluted part of the distal tubule, connecting tubule, cortical collecting duct), which in the desert rodent, Psammomys obesus, transform gradually from one segment to the next, due to intermingling of their different cell types. The convoluted part of the distal tubule (DTC) starts abruptly, shortly beyond the macula densa and initially is homogeneously composed of characteristic DTC-cells. Subsequently, the DTC-cells intermingle with intercalated cells. The first appearance of the connecting-tubule cell, which gradually replaces the DTC-cell, is regarded as the beginning of the connecting tubule. The major portion of the connecting tubule is lined by connecting-tubule cells and intercalated cells. The first appearance of the principal cell between them defines the beginning of the cortical collecting duct, which in the medullary ray is lined by principal and intercalated cells only. Each cell type is described in detail and discussed in relation to the assumed function of the tubular segments. Interspecies differences in the cellular composition of the transitional zone from the nephron to the collecting duct are discussed in relation to the different organization of the collecting duct system.
    Materialart: Digitale Medien
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  • 121
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 213 (1980), S. 433-440 
    ISSN: 1432-0878
    Schlagwort(e): Anterior pituitary ; Microtubules ; Paracrystalline aggregates ; Ultrastructure ; Chinchilla
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Unusual paracrystalline aggregates of microtubules which have not been described in any other mammalian species were observed in cultured anterior pituitary cells of normal chinchillas as well as in situ in the pituitary glands of these animals. These aggregates appeared as regularly arranged tubular structures in the longitudinal plane, and as a checkerboard pattern of closely and regularly packed microtubules when examined in transverse section. Supplementation with vinblastine, colcemide or colchicine in the culture medium did not change these structures morphologically. Each unit of tubules consisted of an outer wall or parellelogram profile and an inner wall composed of a single hexagonal doublet or in a figure “8” form. The outer wall of the parallelogram was 35×28 nm in length for both sides, while the diagonal of the inner wall was 18×28 nm. These paracrystalline aggregates of microtubules in the chinchilla pituitary cells are morphologically distinct from the paracrystalline assembly of cytoplasmic microtubules induced by vinblastine or other alkaloids. The function and significance of these paracrystalline aggregates in anterior pituitary cells of the chinchilla are uncertain.
    Materialart: Digitale Medien
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  • 122
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 213 (1980), S. 475-482 
    ISSN: 1432-0878
    Schlagwort(e): Vaginal epithelium ; Prenatal estrogen treatment ; Mucification ; Ultrastructure ; Mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary After transplacental treatment of mice with estrogens, a heavy mucification was found in the fornices of the vaginae of the offsping. The resulting mucified stratified epithelium is described by light and electron microscopy. It consists of two different cell types: cells forming mucus on top of cells forming tonofilaments. Mucus formation is usually attributed to treatment with progestagens, or with with estrogens combined with vitamin A. Estrogen treatment per se has been shown to be responsible for tonofilament formation. Our unexpected findings are discussed against the background of different theories of development of vaginal epithelium as well as their possible interpretation as beginning of adenosis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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