Vein cells called tunica intima. The precise location of veins varies much more from person to person than that of arteries. Veins serve to return blood from organs to the heart. Veins are also called "capacitance vessels" because most of the blood volume (60%) is contained within veins. In systemic circulation oxygenated blood is pumped by the left ventricle through the arteries to the muscles and organs of the body, where its nutrients and gases are exchanged at capillaries. After taking up cellular waste and carbon dioxide in capillaries, blood is channeled through vessels that converge with one another to form
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.