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
Striate arteries They may either rupture, producing an intracerebral hemorrhage that is initially centered in the region they supply, or they become occluded, producing a lacunar infarct in the tissue they supply. The lenticulostriate arteries are "end arteries", meaning that the regions they supply do not have significant collateral blood supply. Occlusion of these vessels therefore leads to stereotyped stroke syndromes. In the case of the lenticulostriate vessels, hemorrhage may remain localized to the putamen and caudate nucleus, may involve neighboring structures such as the internal capsule and other more distant white matter of the hemisphere, or may even rupture into the