Question

The respiratory membranes facilitates the exchange of respiratory gases through diffusion. Oxygen enters the deoxygenated blood through diffusion because:

• A. Partial pressure of oxygen in alveolar air and capillaries is 40 mm Hg and 104 mm Hg respectively
• B. Partial pressure of oxygen in alveolar air and capillaries is 104 mm Hg and 40 mm Hg respectively
• C. Partial pressure of oxygen in alveolar air and capillaries is 45 mm Hg and 40 mm Hg respectively
• D. Partial pressure of oxygen in alveolar air and capillaries is 40 mm Hg and 45 mm Hg respectively

Answer 1

The correct option is B Partial pressure of oxygen in alveolar air and capillaries is 104 mm Hg and 40 mm Hg respectively

The exchange of gases takes place due to the difference in partial pressure. Partial pressure of oxygen in alveolar air and capillaries is 104 mm Hg and 40 mm Hg, respectively which can be seen in the diagram below.

Due to high partial pressure of oxygen in alveoli than capillaries near alveoli the oxygen get transferred to the blood.