Question

what is the role of the lungs in pulmonary circulation, and how do they contribute to the process of gas exchange?
a the lungs play a crucial role in pulmonary circulation by facilitating gas exchange. in the alveoli of the lungs, carbon dioxide is removed from the blood and replaced with oxygen. this oxygenated blood is then returned to the heart via the pulmonary veins, ready to be pumped into systemic circulation.
b the lungs in pulmonary circulation are responsible for pumping blood throughout the body.
c the lungs in pulmonary circulation store oxygen and release it directly into the bloodstream without any gas exchange.

Explanation:

To determine the correct answer, we analyze each option:

• Option A: The lungs' alveoli facilitate gas exchange (CO₂ out, O₂ in), oxygenated blood returns to the heart via pulmonary veins. This matches the role of lungs in pulmonary circulation and gas exchange.
• Option B: The heart, not the lungs, pumps blood throughout the body. So B is incorrect.
• Option C: Lungs don't store oxygen; gas exchange (diffusion) occurs in alveoli. So C is incorrect.

Answer:

A. The lungs play a crucial role in pulmonary circulation by facilitating gas exchange. In the alveoli of the lungs, carbon dioxide is removed from the blood and replaced with oxygen. This oxygenated blood is then returned to the heart via the pulmonary veins, ready to be pumped into systemic circulation.