The coronary arteries primarily supply blood to which heart tissue?

• A. The myocardium
• B. The endocardium
• C. The epicardium
• D. The pericardium

Answer: (A)

Coronary arteries deliver oxygenated blood to the heart muscle, the myocardium. This thick muscular layer has the greatest metabolic demand and relies on coronary flow to sustain contraction. The coronary vessels run on the heart’s outer surface (the epicardium) and branch inward to reach the myocardium, supplying the tissue that actually does the pumping. The endocardium (inner lining) and epicardium (outer surface) are nourished by the same coronary circulation, but they aren’t the primary tissues these arteries exist to perfuse in the way the myocardium is. The pericardium is the surrounding sac and has its own separate blood supply, not chiefly from the coronary arteries. So, the tissue primarily supplied by the coronary arteries is the myocardium.