| Autor: |
Scheid, Peter, Fedde, M. Roger, Piiper, Johannes |
| Zdroj: |
The Journal of Experimental Biology; March 1989, Vol. 142 Issue: 1 p373-385, 13p |
| Abstrakt: |
Gas exchange variables were measured in unanaesthetized domestic geese fitted with rubber facemasks and indwelling air-sac and arterial catheters. The results were analysed on the basis of functional models. Ventilation was characterized by low frequency (8·4 min−1) and high tidal volume (29·3 ml kg−1). Average values (± S.E.) of arterial blood variables were as follows: kPa, pH = 7·52 ± 0·01. Body temperature was 41·4 ± 0·2°C. The gas exchange ratio (calculated with reference to inspired gas) of caudal air sacs (average 1·09) was higher, and that of cranial air sacs (0·73) lower, than that of mixed-expired (0·82) or end-expired gas (0·78). This pattern can be explained by a higher effective ventilation/perfusion ratio in the neopulmo than in the paleopulmo. During inspiration, the neopulmo was estimated to contribute about 7% to the overall inspiratory O2 uptake, and about 18% to the CO2 output. Total inspiratory gas exchange was twice that during expiration. Arterial , was close to, but lower than, the partial pressure in cranial air sacs and in end-expired gas. This can be explained on the basis of a crosscurrent gas exchange system with unequal distribution of ventilation to perfusion between functional compartments. |
| Databáze: |
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