Question

Diffusion of oxygen into the blood in pulmonary capillaries would occur when the partial pressure of the alveolar air is ___ mm Hg and the partial pressure of the blood in pulmonary capillaries is ___ mm Hg.

Answer 1

Oxygen diffuses into the blood when the partial pressure in alveolar air is about 104 mm Hg and in the pulmonary capillaries is about 40 mm Hg. This strong pressure gradient facilitates the rapid diffusion of oxygen across the respiratory membrane.

Step-by-step explanation:

Diffusion of oxygen into the blood in pulmonary capillaries would occur when the partial pressure of the alveolar air is 104 mm Hg and the partial pressure of the blood in pulmonary capillaries is 40 mm Hg. This large difference in partial pressure, which is about 64 mm Hg, creates a strong pressure gradient that causes oxygen to rapidly cross the respiratory membrane from the alveoli into the blood. Even though the solubility of oxygen is not high, the high solubility of carbon dioxide, which is about 20 times greater than that of oxygen, ensures that the relative concentrations of both gases that diffuse across the respiratory membrane are similar.

The body has mechanisms to maximize the efficiency of gas exchange. In cases where ventilation is inadequate, it can redirect blood flow to well-ventilated alveoli by constricting pulmonary arterioles serving deficient alveoli and dilating those serving well-ventilated alveoli.

Answer 2

The correct answer is - 105, and 40.

Step-by-step explanation:

In the case of the of the partial pressure of of oxygen in the alveolar air is about 105 mm Hg whereas the partial pressure of blood in pulmonary capillaries is about 40 mm Hg it result in the diffusion of oxygen into the blood in pulmonary capillaries would occur.

Due to the low partial pressure of blood in pulmonary capillaries and high in alveolar air is high, the result in diffusion of oxygen across the respiratory membrane.

Thus, the correct answer is - 105, and 40