Question

The exchange of gases between the alveoli and blood in the lungs, as well as between blood and tissue, depends on

• A. Pressure of the gases
• B. Partial pressure of the gases
• C. Pressures and the diffusion capacity of the gases
• D. Diffusion capacity of the gases

Answer 1

The correct option is B

Partial pressure of the gases

Partial pressure is the pressure exerted by each gas in a mixture of gases. It depends on the concentration of the gas in the mixture. Partial pressure a particular gas in the mixture is higher if the concentration of that gas is more. Thus, the gases diffuse across the membrane from the region of its higher partial pressure to the region of its lower partial pressure.