Which vessels supply oxygenated blood to the heart muscle?

• A. Right and left coronary arteries
• B. Pulmonary arteries
• C. Pulmonary veins
• D. Coronary sinus

Answer: (A)

Oxygen-rich blood to the heart muscle comes through the coronary arteries, which arise from the aorta just above the aortic valve and spread over the heart to nourish the myocardium. This coronary circulation is specifically responsible for delivering the oxygen the myocardium relies on for energy.

The pulmonary arteries are part of the pulmonary circulation and carry deoxygenated blood from the right ventricle to the lungs. The pulmonary veins return oxygenated blood from the lungs to the left atrium, but they deliver blood back to the heart chambers, not to the heart muscle itself. The coronary sinus is a large vein that collects deoxygenated blood from the heart muscle and drains it into the right atrium, not supplying the muscle with oxygen.

So the vessels that supply the heart muscle with oxygenated blood are the right and left coronary arteries.