According to the described pulmonary circulation sequence, which vessels return blood from the lungs to the heart?

• A. Inferior vena cava.
• B. Pulmonary arteries.
• C. Pulmonary veins.
• D. Aorta.

Answer: (C)

In the pulmonary circuit, blood that has been oxygenated in the lungs returns to the heart through the pulmonary veins. These vessels drain into the left atrium, after which the blood moves to the left ventricle and then into the body. The inferior vena cava brings blood back from the body to the right atrium, not from the lungs. The pulmonary arteries carry blood from the heart to the lungs, not back to the heart. The aorta distributes blood from the left ventricle to the systemic circulation, not from the lungs to the heart.