Vein they were for transport of air. The Greek physician, Herophilus, distinguished veins from arteries but thought that the pulse was a property of arteries themselves. Greek anatomist Erasistratus observed that arteries that were cut during life bleed. He ascribed the fact to the phenomenon that air escaping from an artery is replaced with blood that entered by very small vessels between veins and arteries. Thus he apparently postulated capillaries but with reversed flow of blood. In 2nd century AD Rome, the Greek physician Galen knew that blood vessels carried blood and identified venous (dark red) and arterial (brighter and thinner)
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.