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
Arcuate vessels of uterus Arcuate vessels of uterus The arcuate vessels of the uterus are a component of the blood supply of the uterus. They are arteries and veins that branch from the uterine arteries and veins, respectively, with additional anastomoses from the ovarian arteries and veins, and penetrate and assume a circumferential course in the myometrium. They have also been called helicine branches of the uterus (or helicine arterioles), as they are spiral-shaped, but they should not be confused with the spiral arteries that penetrate the endometrium in the inner uterus. The radial arteries branch off from the arcuate artery through the myometrium.