Like any other organ or tissue in the body, your heart requires its own blood supply to get the oxygen and nutrition it needs for energy to contract again and again. Although the chambers of the heart are filled with blood, the heart muscle does not extract oxygen and nutrients from the blood in its chambers. The heart receives its nourishing blood supply through the coronary arteries. Because of its heavy work load, the heart requires a particularly rich blood supply. At rest, the blood flow through the coronary arteries averages about 225 milliliters (more than 7 ounces) per minute. This amount is 4 to 5 percent of the blood pumped by the heart, even though the heart makes up less than 1 percent of the body's weight.

Location of the Coronary Arteries

The coronary arteries branch off from the base of the aorta just above the aortic valve. They run along the surface of the heart, encircling the top and branching toward the bottom like a crown {corona means "crown," hence their name).

The coronary arteries each have many branches like a tree. The trunks and large branches of the arteries run along the outer surface of your heart. Each trunk is about the size of a soda straw. The smaller branches penetrate into the heart muscle, going from the outside toward the inner surface of the cardiac chambers to carry blood to the myocardial cells.

The smaller arteries branch into even smaller vessels and ultimately into capillaries. The capillaries are the points at which oxygen and nutrients are exchanged for waste products.

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