Diffusion of Gases — MCQ Practice

Which of the following factors would lead to a decrease in the rate of diffusion of gases across the alveolar membrane?

The partial pressure of oxygen ($PO_2$) in the atmospheric air at sea level is approximately $159,\text{mmHg}$. If the total atmospheric pressure is $760,\text{mmHg}$, what is the approximate percentage of oxygen in the atmosphere?

Which of the following statements about the diffusion of $CO_2$ and $O_2$ across the respiratory membrane is correct?

In a healthy individual, the partial pressure of oxygen ($PO_2$) in the alveolar air is approximately $104,\text{mmHg}$, while in the deoxygenated blood entering the pulmonary capillaries, it is approximately $40,\text{mmHg}$. What is the partial pressure gradient for oxygen that drives its diffusion into the blood?

A patient is diagnosed with pulmonary fibrosis, a condition that causes thickening of the alveolar-capillary membrane. Which of the following consequences would be most likely observed regarding gas exchange?

Which of the following partial pressure values for $O_2$ and $CO_2$ are characteristic of deoxygenated blood in the systemic veins?