Red blood cell synthesised by the kidney. Just before and after leaving the bone marrow, the developing cells are known as reticulocytes; these constitute about 1% of circulating red blood cells. The functional lifetime of a red blood cell is about 100–120 days, during which time the red blood cells are continually moved by the blood flow push (in arteries), pull (in veins) and a combination of the two as they squeeze through microvessels such as capillaries. They are also recycled in the bone marrow. The aging red blood cell undergoes changes in its plasma membrane, making it susceptible to selective recognition by
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