Schematic diagram of the<unk>  arteries and veins. Schematic view of the heart An anterior left<unk>  artery. Base and diaphragmatic surface of heart.<unk>  arteries supply blood to the myocardium and other components of the heart. Two<unk>  arteries originate from the left side of the heart at the beginning (root) left ventricle. There are three aortic sinuses (dilations) in the wall of the aorta just superior to the aortic semilunar valve. Two of these, the left posterior aortic sinus and anterior aortic sinus, give rise to the left and right<unk>  arteries, respectively. The third sinus, the right posterior aortic sinus, typically does not give rise to a vessel.<unk>  vessel branches that remain on the surface of the heart and follow the sulci of the heart are called epicardial<unk>  arteries. The left<unk>  artery distributes blood to the left side of the heart, the left atrium and ventricle, and the interventricular septum. The circumflex artery arises from the left<unk>  artery and follows the<unk>  sulcus to the left. Eventually, it will fuse with the small branches of the right<unk>  artery. The larger anterior interventricular artery, also known as the left anterior descending artery (LAD), is the second major branch arising from the left<unk>  artery. It follows the anterior interventricular sulcus around the pulmonary trunk. Along the way it gives rise to numerous smaller branches that interconnect with the branches of the posterior interventricular artery, forming anastomoses. An anastomosis is an area where vessels unite to form interconnections that normally allow blood to circulate to a region even if there may be partial blockage in another branch. The anastomoses in the heart are very small. Therefore, this ability is somewhat restricted in the heart so a<unk>  artery blockage often results in myocardial infarction causing death of the cells supplied by the particular vessel. The right<unk>  artery proceeds along the<unk>  sulcus and distributes blood to the right atrium, portions of both ventricles, and the heart conduction system. Normally, one or more marginal arteries arise from the right<unk>  artery inferior to the right atrium. The marginal arteries supply blood to the superficial portions of the right ventricle. On the posterior surface of the heart, the right<unk>  artery gives rise to the posterior interventricular artery, also known as the posterior descending artery. It runs along the posterior portion of the interventricular sulcus toward the apex of the heart, giving rise to branches that supply the interventricular septum and portions of both ventricles. Anastomoses Cast of<unk>  arteries (right = yellow, left = red) There are some anastomoses between branches of the two<unk>  arteries. However the<unk>  arteries are functionally end arteries and so these meetings are referred to as potential anastomoses, which lack function, as opposed to true anastomoses like that in the palm of the hand. This is because blockage of one<unk>  artery generally results in death of the heart tissue due to lack of sufficient blood supply from the other branch. When two arteries or their branches join, the area of the myocardium receives dual blood supply. These junctions are called anastomoses. If one<unk>  artery is obstructed by an atheroma, the second artery is still able to supply oxygenated blood to the myocardium. However, this can only occur if the atheroma progresses slowly, giving the anastomoses a chance to proliferate. Under the most common configuration of<unk>  arteries, there are three areas of anastomoses. Small branches of the LAD (left anterior descending/anterior interventricular) branch of the left<unk>  join with branches of the posterior interventricular branch of the right<unk>  in the interventricular sulcus (groove). More superiorly, there is an anastomosis between the circumflex artery (a branch of the left<unk>  artery) and the right<unk>  artery in the atrioventricular groove. There is also an anastomosis between the septal branches of the two<unk>  arteries in the interventricular septum. The photograph shows area of heart supplied by the right and the left<unk>  arteries. Variation The left and right<unk>  arteries occasionally arise by a common trunk, or their number may be increased to three; the additional branch being the posterior<unk>  artery (which is smaller in size). In rare cases, a person will have the third<unk>  artery run around the root of the aorta. Occasionally, a<unk>  artery will exist as a double structure (i.e. there are two arteries, parallel to each other, where ordinarily there would be one).<unk>  artery dominance The artery that supplies the posterior third of the interventricular septum – the posterior descending artery (PDA) determines the<unk>  dominance. * If the posterior descending artery is supplied by the right<unk>  artery (RCA), then the<unk>  can be classified as "right-dominant." * If the posterior descending artery is supplied by the circumflex artery (CX), a branch of the left artery, then the<unk>  can be classified as "left-dominant." * If the posterior descending artery is supplied by both the right<unk>  artery and the circumflex artery, then the<unk>  can be classified as "co-dominant." Approximately 70% of the general population are right-dominant, 20% are co-dominant, and 10% are left-dominant. A precise anatomic definition of dominance would be the artery which gives off supply to the AV node i.e. the AV nodal artery. Most of the time this is the right<unk>  artery.
Coronary circulation
Cardiac cycle
Arterial tree
Electrical conduction system of the heart
Myocardial contractility
Autonomic nervous system
Limb perfusion
Vagal tone