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
Endometrial arteries blood to the endometrium but are also beneficial during pregnancy. When a female is pregnant a placenta develops. The baby receives blood, nutrients and oxygen via the umbilical cord which is attached to the placenta. Between the placenta and the myometrium are intervillous spaces where the endometrial arteries supply blood to. The placenta has villous trees which allow for blood to circulate and then be transported to the baby via the placenta. Endometrial arteries are divided into the common ones and the arteriovenous anastomosis. The common ones are arteries that are homologous to the arteries of the rest of the