The heart is a muscle like any other in the body. Arteries supply it with oxygen-rich blood so that it can contract and push blood to the rest of the body. When there isn’t enough oxygen flow to a muscle, its function begins to suffer. Block the oxygen supply completely, and the muscle starts to die. Heart muscle gets its blood supply from arteries that originate in the aortajust as it leaves the heart. The coronary arteries run along the surface of the heart and supply oxygen-rich blood to the heart muscle. The right coronary artery supplies the right ventricle of the heart and the inferior (lower) portion of the left ventricle. The left anterior descending coronary artery supplies the majority of the left ventricle, while the circumflex artery supplies the back of the left ventricle. The ventricles are the lower chambers of the heart; the right ventricle pumps blood to the lungs and left pumps it to the rest of the body.