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
Face transplant the sinuses around the nose, the upper jaw, and even some teeth from a brain-dead donor. As doctors recovered the donor's facial tissue, they paid special attention to maintaining arteries, veins, and nerves, as well as soft tissue and bony structures. The surgeons then connected facial graft vessels to the patient's blood vessels in order to restore blood circulation in the reconstructed face before connecting arteries, veins and nerves in the 22-hour procedure. She had been disfigured to the point where she could not eat or breathe on her own as a result of a traumatic injury several years ago,