Q.
The diffusing capacity for carbon dioxide compared to that for oxygen is
1595
184
Breathing and Exchange of Gases
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Solution:
Diffusion of CO2 occurs from the lungs' capillary blood to the alveoli due to difference in pressures. Although this CO2 diffusion gradient is only one tenth of the O2 gradient, CO2 diffuses 20 times more rapidly than O2 because it is 25 times more soluble in body fluids. The average CO2 pressure in the capillary blood is 46mmHg as opposed to 40mmHg in alveoli. Whereas, normal O2 pressure is 100mmHg in alveoli and 40mmHg in lung capillaries.