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Question:

Gas exchange between the blood and alveoli would be enhanced by ______________, but impeded by __________________.

A increased alveolar surface area; increased membrane thickness
Explaination

Gas exchange in the lung can be explained by Fick’s Law of Diffusion, which is represented by the following equation:
Diffusion = k * SA * ( P2 – P1)⁄T
where k represents the diffusion coefficient for the specific gas, SA represents the surface area of the tissue, P2- P1 represents the difference in the gas concentration on one side of the membrane compared to the other side, and T represents the thickness of the tissue.
Thus, any increases in gas coefficient, surface area, or difference in pressure will enhance gas exchange, while any increase in tissue thickness will impede gas exchange.