Comperative Aspects of Respiration and Circulation in Mammals
Adaptational mechanisms concerning the higher metabolic rate in small mammals compared to big ones are discussed. The alveolar gas exchange area is relatively larger in small mammals, because the individual alveoli are smaller. The capillarization of muscle tissue is higher in small mammals like mice and small bats. Ventilation and cardiac index increase in correlation to metabolic rate. Blood oxygen affinity is lower in small mammals supporting oxygen delivery into tissue. From the point of view of comparative respiratory and circulatory physiology man has all the biological advantages to be “average”.
Key wordsAlveoli Capillarization Gas diffusion Cardiac index Ventilation Oxygen affinity Bohr effect Altitude 2, 3-diphosphoglycerate Cytochrome oxidase Camel Llama Elephant Bat Mouse
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