Arteries are not only blood vessels, but also an important part of blood vessels. Blood vessels according to its function, size, can be divided into arteries, veins and capillaries, in general the structure of the circulatory system to the heart as a starting point in turn is the arteries, tissue capillaries, veins, the heart, a blood circulation, so the arteries are the blood flow out of the heart until the tissue between the blood vessels between the capillaries, and its function is to provide blood for the organs and tissues. Arteries can be subdivided into large arteries, medium arteries, small arteries and micro-arteries, in which there is a special structure at the beginning of the micro-arteries, called micro-arterial vascular sphincter, this structure is like a spring coil, through the contraction and diastolic activity to regulate the size of arterial diameter, thus regulating the amount of blood flowing through different parts of the body.