Cardiac muscle cells rely on an ample blood supply to deliver oxygen and nutrients and to remove waste products such as carbon dioxide. The coronary arteries fulfill this function.
The vessels that deliver oxygen-rich blood to the myocardium are known as coronary arteries. The vessels that remove the deoxygenated blood from the heart muscle are known as cardiac veins. Approximately 4 - 5 percent of the blood output of the heart goes to the coronary arteries. The branches of the coronary arteries supply blood to different parts of the heart muscle.