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
Intercostal arteries nerve of the given space. The vein is superior to the artery, and the intercostal nerve is inferior to it. Commonly, the mnemonic, "Van," is used to recall the order of the vein, artery and nerve, from superior to inferior. Intercostal arteries The intercostal arteries are a group of arteries that supply the area between the ribs ("costae"), called the intercostal space. The highest intercostal artery (supreme intercostal artery or superior intercostal artery) is an artery in the human body that usually gives rise to the first and second posterior intercostal arteries, which supply blood to their corresponding intercostal space.