Which vessels siphon off a share of oxygenated blood to supply the heart muscle?

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

Answer: (A)

Blood that nourishes the heart muscle comes from the coronary arteries. These vessels branch off the aorta just after the aortic valve and deliver oxygen-rich blood directly to the myocardium. The aorta itself feeds the rest of the body, not specifically the heart muscle. The pulmonary veins bring oxygenated blood from the lungs to the left atrium, not to the heart muscle as a supplier. The superior vena cava returns deoxygenated blood to the right atrium. So, the coronary arteries are the vessels that siphon off oxygenated blood to supply the heart muscle. (Note: coronary perfusion mainly occurs during diastole when the heart is relaxed.)