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  • 1
    Electronic Resource
    Electronic Resource
    Cardiorespiratory responses of the woodchuck and porcupine to CO2 and hypoxia (1989)
    Springer
    Journal of comparative physiology 159 (1989), S. 641-648 
    Details
    ISSN: 1432-136X
    Keywords: Cardiorespiratory responses ; Woodchuck ; Porcupine ; CO2 ; Hypoxia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The burrow-dwelling woodchuck (Marmota monax) (mean body wt.=4.45±1 kg) was compared to a similar-sized (5.87±1.5 kg) but arboreal rodent, the porcupine (Erithrizon dorsatum), in terms of its ventilatory and heart rate responses to hypoxia and hypercapnia, and its blood characteristics.V T,f,T I andT E were measured by whole-body plethysmography in four awake individuals of each species. The woodchuck has a longerT E/T TOT (0.76±0.03) than the porcupine (0.61±0.03). The woodchuck had a higher threshold and significantly smaller slope to its CO2 ventilatory response compared to the porcupine, but showed no difference in its hypoxic ventilatory response. The woodchuck P50 of 27.8 was hardly different from the porcupine value of 30.7, but the Bohr factor, −0.72, was greater than the porcupine's, −0.413. The woodchuck breathing air has PaCO2=48 (±2) torr, PaO2=72 (±6), pHa=7.357 (±0.01); the porcupine blood gases are PaCO2=34.6 (±2.8), PaO2=94.9 (±5), pHa=7.419 (±0.03), suggesting a difference in PaCO2/pH set points. The woodchuck exhibited no reduction in heart rate with hypoxia, nor did it have the low normoxic heart rate observed in other burrowing mammals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00694390
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  • 2
    Electronic Resource
    Electronic Resource
    Ventilatory responses of the burrowing Owl and Bobwhite to hypercarbia and hypoxia (1983)
    Springer
    Journal of comparative physiology 149 (1983), S. 527-533 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fractional concentration of CO2 within the occupied burrows of burrow-dwelling birds has been measured at 0.065 or higher while the fractional concentration of O2 can be 0.14 or lower. The ventilatory responses of the Burrowing Owl (Athene cunicularia) and a non-burrowing bird, the Bobwhite (Colinus virginianus), to the levels of hypercarbia, hypoxia and hypoxic hypercarbia likely encountered by this owl within its burrow were assessed. Ventilatory responses toFi CO 2 of 0.01, 0.03, 0.05 and 0.07 at normoxia; toFi CO 2 of 0.19, 0.17, 0.15 and 0.13 at normocarbia; and to combinedFi CO 2 andFi O 2 of 0.01:0.19, 0.03:0.17, 0.05:0.15 and 0.07:0.13 were measured by volumetric plethysmography. The Burrowing Owl exhibited a significantly attenuated ventilatory response to these levels of hypercarbia, hypoxia and hypoxic hypercarbia compared to the non-burrow-dwelling Bobwhite. A reduced ventilatory response to the hypoxic and hypercarbic stimuli has been previously observed in fossorial mammals, and is reported here for the first time in a burrow-dwelling bird. This reduced response is believed to represent an adaptation to burrow atmospheric conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690012
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  • 3
    Electronic Resource
    Electronic Resource
    Role of theRete mirabile ophthalmicum in maintaining the body-to-brain temperature difference in pigeons (1979)
    Springer
    Journal of comparative physiology 129 (1979), S. 119-122 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Brain (hypothalamic) and colonic temperatures were measured in twenty adult pigeons (Columba livia) whose mean body mass was 0.377 kg. 2. In contrals, in sham operated birds, and in those pigeons in which one or both external ophthalmic arteries were occluded brain temperatures were always about 1°C (0.94 to 1.03) below body temperature (Fig. 2) over a range of air temperatures. 3. In pigeons in which arterial flow to theretia was totally blocked, the normal pattern of body-to-brain temperature difference wasreversed, such that brain temperature was always higher than body temperature by a mean of 0.36 °C (Fig. 2, Table 1). 4. Therete mirabile ophthalmicum of pigeons plays a central role in the maintenance of the body-to-brain temperature difference which may be important in avoiding brain damage during core hyperthermia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00798175
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  • 4
    Electronic Resource
    Electronic Resource
    Neuromuscular organization and regional EMG activity of the pectoralis in the pigeon (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 43-57 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In order to improve our understanding of the neuromuscular control of the most massive avian flight muscle, we studied the innervation pattern of the pigeon pectoralis. Nine primary branches from the rostral trunk and nine to ten branches from the caudal trunk of the pectoral nerve were identified by microdissection in ten pigeons. The region of muscle that each branch innervates was delineated by nerve stimulation studies (ten pigeons) and six regions were confirmed by glycogen depletion (ten pigeons). In pigeons, branches from the rostral nerve innervate the anterior 3/5 of the sternobrachialis (SB) head of the pectoralis and branches from the caudal trunk innervate the posterior 1/2 of the SB and all of the throacobrachials (TB). In the SB, individual branches of the rostral pectoral nerve innervate wedge-shaped muscle regions (each approximately 1.3 cm wide), collectively forming a fan shaped arrangement along the sternal carina. Adjacent muscle regions partially overlap at their boundaries. Within the thoracobrachialis (TB) head of the pectrolis, muscle regions are wider. There is a region in mid-SB-where the innervation territories of the rostral and caudal nerves oferlap. Electromyographic (EMG) activity patterns were recorded within ten of the identified muscle regions during take-off, level flapping flight, and landing. Onset of EMG activity and EMG intensity within various muscle regions exhibits significant differences both within a wingbeat cycle and among different modes of flight. The innervation pattern of the pectoralis presents the anatomical substrate for neuromuscular compartmentalization and differential EMG activity within the pectoralis may reflect sensory-motor partitioning. The extent to which the neuromuscular compartmentalization of the pectoralis corresponds to its ability to produce an array of force vectors to the wing awaits further more detailed biomechanical studies. © 1993 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052180104
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