Capillary embryonic development new capillaries are formed through vasculogenesis, the process of blood vessel formation that occurs through a "de novo" production of endothelial cells which then form vascular tubes. The term angiogenesis denotes the formation of new capillaries from pre-existing blood vessels and already present endothelium which divides. Blood flows from the heart through arteries, which branch and narrow into arterioles, and then branch further into capillaries where nutrients and wastes are exchanged. The capillaries then join and widen to become venules, which in turn widen and converge to become veins, which then return blood back to the heart through
Blood vessel diffuse vascular supply it is called an anastomosis. Anastomoses provide critical alternative routes for blood to flow in case of blockages. There is a layer of muscle surrounding the arteries and the veins which help contract and expand the vessels. This creates enough pressure for blood to be pumped around the body. Blood vessels are part of the circulatory system, together with the heart and the blood. The biggest difference in the structure of arteries and veins is the presence of valves. Backflow of blood is prevented in arteries by the heart. However in veins, one-direction valves are used to