Question

Diffusion of gases over the respiratory surface occurs because of ______.

Options

• the pCO₂ is more in alveoli than in blood

• the pCO₂ is more in blood than in tissues

• the pO₂ is more in alveoli than in blood

• the pO₂ is more in tissues than in blood

Answer 1

Diffusion of gases over the respiratory surface occurs because of the pO₂ is more in alveoli than in blood.

Explanation:

Because pO₂ is higher in alveoli (104 mm Hg) than in blood, gases spread over the respiratory surface (40 mm Hg).