Which side of the heart contains blood that is low in oxygen and high in carbon dioxide?

• A. Right side of the heart
• B. Left side of the heart
• C. The heart receives blood from both sides
• D. The coronary arteries supply the left ventricle

Answer: (A)

Deoxygenated blood that returns from the body is carried to the right side of the heart. It enters the right atrium via the superior and inferior vena cavae, moves into the right ventricle, and is pumped to the lungs through the pulmonary artery for gas exchange. After picking up oxygen and releasing carbon dioxide in the lungs, the blood returns to the left side of the heart via the pulmonary veins and then is pumped to the body. So the right side handles blood that is low in oxygen and high in carbon dioxide. The left side, in contrast, receives oxygenated blood from the lungs. The statement that the heart receives blood from both sides doesn’t address oxygen content, and the note about coronary arteries supplying the left ventricle concerns coronary circulation rather than the oxygenation status of the chambers.