Which of the following best describes pulmonary circulation?

Which of the following best describes pulmonary circulation?

• A. From the right ventricle to the body tissues and back to the left atrium
• B. From the left atrium to the right ventricle
• C. From the right side of the heart to the lungs for gas exchange and back to the left side
• D. From the left ventricle to the aorta

Answer: (C)

Pulmonary circulation is the pathway that carries blood from the right side of the heart to the lungs for gas exchange and back to the left side. Blood leaves the right ventricle through the pulmonary arteries to the lungs, where carbon dioxide is released and oxygen is picked up. The oxygen-rich blood then returns to the left atrium via the pulmonary veins. This gas exchange happens in the alveolar-capillary network of the lungs. This is different from systemic circulation, which sends blood from the left ventricle to the rest of the body and back to the right atrium. The flow from the left atrium to the right ventricle describes movement within the heart but doesn’t complete the lungs-based gas-exchange loop, and the flow from the left ventricle to the aorta is the arterial distribution to the body, not the lungs.

Pulmonary circulation is the pathway that carries blood from the right side of the heart to the lungs for gas exchange and back to the left side. Blood leaves the right ventricle through the pulmonary arteries to the lungs, where carbon dioxide is released and oxygen is picked up. The oxygen-rich blood then returns to the left atrium via the pulmonary veins. This gas exchange happens in the alveolar-capillary network of the lungs.

This is different from systemic circulation, which sends blood from the left ventricle to the rest of the body and back to the right atrium. The flow from the left atrium to the right ventricle describes movement within the heart but doesn’t complete the lungs-based gas-exchange loop, and the flow from the left ventricle to the aorta is the arterial distribution to the body, not the lungs.