Which of the following would decrease diffusion of a gas across the alveolar/pulmonary capillary membrane?
A) an increase in thickness of the membrane
B) an increase in surface area of the membrane
C) an increase in the partial pressure gradient
D) an increase in thickness of the membrane and an increase in the partial pressure gradient
E) all of these

Question

Quizplus · Accepted Answer

An increase in thickness of the alveolar/pulmonary capillary membrane would create a barrier for the gas to diffuse across, slowing down or decreasing the diffusion process. Increasing the surface area of the membrane would actually increase the diffusion of gas. Increasing the partial pressure gradient would also increase the diffusion of gas. Therefore, choices B and C are not the best answers. D is incorrect as well because even though an increase in partial pressure gradient would increase diffusion, an increase in membrane thickness would decrease diffusion. Therefore, the best answer is A.

Which of the Following Would Decrease Diffusion of a Gas