Which statements explain the gas exchange that happens at the alveoli? Check all that apply.

Question

Carbon dioxide moves from the air in the alveoli to the blood.
Carbon dioxide moves from the blood to the air in the alveoli.
The capillaries that surround the alveoli exchange both carbon dioxide and oxygen.
The capillaries that surround the alveoli exchange only oxygen.
Oxygen is absorbed by the blood in the capillaries that surround the alveoli.
Oxygen is the air we breathe out when we exhale.

Answer 1

The correct statements that explain the gas exchange that happens at the alveoli are:

1. Carbon dioxide moves from the blood to the air in the alveoli.
2. The capillaries that surround the alveoli exchange both carbon dioxide and oxygen.
3. Oxygen is absorbed by the blood in the capillaries that surround the alveoli.

The following statements are not accurate:

• Carbon dioxide moves from the air in the alveoli to the blood. (This does not happen; carbon dioxide moves from the blood to the alveoli.)
• The capillaries that surround the alveoli exchange only oxygen. (This is incorrect; they exchange both oxygen and carbon dioxide.)
• Oxygen is the air we breathe out when we exhale. (This is misleading; we primarily exhale carbon dioxide, although some oxygen may still be present in exhaled air.)