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 Endometrial arteries Arcuate arteries located in the uterus branch out and supply blood to different layers of the uterus. These arteries meet the myometrial-endometrial junction and lead to straight and endometrial arteries. The endometrium receives blood from endometrial arteries which are also called spiral arteries. Endometrial arteries proliferate rapidly and react to different hormones released. These hormones are progesterone and estrogen released by the ovaries and produced by the endocrine system. The endometrial arteries not only supply blood to the endometrium but are also important during pregnancy. They are the initial site of transportation of blood from the mother to