There are two major coronary arteries: the right and the left. These two arteries branch out of the aorta immediately after the aortic valve. The right coronary artery splits into the marginal branch, which feeds blood into the right ventricle, and the posterior interventricular branch, which supplies the left ventricle. The left coronary artery is notably larger than the right coronary artery because it feeds the left heart, which, as a result of it's more powerful contractions, requires a more vigorous blood flow. The left coronary artery splits into the anterior interventricular branch and a circumflex branch. The anterior interventricular branch runs towards the apex of the heart, providing blood for both of the ventricles and the ventricular septum. The circumflex branch, on the other hand, follows the groove between the left atrium and the left ventricle, providing blood supply to both of these chambers until it reaches and joins with the right coronary artery in the posterior of the heart.
coronary arteries are especially subject to blockage
and narrowing which can cause a depletion of blood to certain parts of the heart,
possibly causing a heart attack.
Most people believe that the heart does not need arteries supplying it with blood since blood is passing though it all the time. However, the truth is that the blood which passes thorough the chambers of the heart does not supply the heart muscle itself because a coating called the endocardium lines the inside of the chambers. But even if this lining did not exist the blood supply provided simply by contact between the passing blood and the inside of the muscle walls would not be nearly enough because the muscle of the heart is the hardest working muscle in the body. Coronary circulation provides an amazing amount of capillaries to the the cardiomyocytes. There is a capillary near almost every cardiomyocyte.