Question

According to Fick's Law, which of the following would decrease diffusion of a gas across the alveolar/pulmonary capillary membrane? Select one: a. an accumulation of mucus along the alveolar lining b. an increase in membrane surface area c. an increase in the partial pressure gradient d. two of these are correct e. all of the above are correct

Answer 1

According to Fick's law of diffusion the rate of diffusion is proportional to both the surface area and concentration difference and is inversely proportional to the thickness of the membrane.

So the answer is option A, an accumulation of mucus along the alveolar lining will decrease the gas exchange across the alveolar/ pulmonary capillary membrane. Because accumulation of mucus is increase the thickness of membrane. So it decreases the gas exchange.

According to Fick's law increase in membrane surface area and increase in partial pressure gradient or concentration will increase the gas exchange through membrane. So those options are wrong.