When blood flowing in a pulmonary capillary first arrives at an alveolus,the concentration of
A) oxygen will be lower in the alveolus than in the blood plasma.
B) carbon dioxide will be greater in the alveolus than in the blood plasma.
C) carbon dioxide will be greater in the blood plasma than in the alveolus.
D) carbon dioxide in the blood plasma will be approximately equal to its concentration in the alveolus.

Question

Quizplus · Accepted Answer

When blood first arrives at an alveolus, it is coming from the body where it has collected carbon dioxide (a waste product of metabolism). Therefore, the concentration of carbon dioxide will be greater in the blood plasma than in the alveolus, facilitating its diffusion out of the blood and into the alveolar air to be exhaled.

When Blood Flowing in a Pulmonary Capillary First Arrives at an Alveolus,the