Document Detail


Control of breathing and adaptation to high altitude in the bar-headed goose.
MedLine Citation:
PMID:  17491113     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The bar-headed goose flies over the Himalayan mountains on its migratory route between South and Central Asia, reaching altitudes of up to 9,000 m. We compared control of breathing in this species with that of low-altitude waterfowl by exposing birds to step decreases in inspired O(2) under both poikilocapnic and isocapnic conditions. Bar-headed geese breathed substantially more than both greylag geese and pekin ducks during severe environmental (poikilocapnic) hypoxia (5% inspired O(2)). This was entirely due to an enhanced tidal volume response to hypoxia, which would have further improved parabronchial (effective) ventilation. Consequently, O(2) loading into the blood and arterial Po(2) were substantially improved. Because air convection requirements were similar between species at 5% inspired O(2), it was the enhanced tidal volume response (not total ventilation per se) that improved O(2) loading in bar-headed geese. Other observations suggest that bar-headed geese depress metabolism less than low-altitude birds during hypoxia and also may be capable of generating higher inspiratory airflows. There were no differences between species in ventilatory sensitivities to isocapnic hypoxia, the hypoxia-induced changes in blood CO(2) tensions or pH, or hypercapnic ventilatory sensitivities. Overall, our results suggest that evolutionary changes in the respiratory control system of bar-headed geese enhance O(2) loading into the blood and may contribute to this species' exceptional ability to fly high.
Authors:
Graham R Scott; William K Milsom
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-05-09
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  293     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2007 Jul 
Date Detail:
Created Date:  2007-07-04     Completed Date:  2007-08-30     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R379-91     Citation Subset:  IM    
Affiliation:
Department of Zoology, University of British Columbia, Vancouver, BC, Canada. scott@zoology.ubc.ca
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MeSH Terms
Descriptor/Qualifier:
Acclimatization / physiology*
Altitude*
Animals
Blood Gas Analysis
Carbon Dioxide / blood
Ducks / physiology
Geese / physiology*
Hydrogen-Ion Concentration
Oxygen / blood
Oxygen Consumption / physiology
Phylogeny
Plethysmography
Respiratory Mechanics / physiology*
Species Specificity
Tidal Volume / physiology
Chemical
Reg. No./Substance:
124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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