Blood Vessels Royalty-Free Stock Photo

Blood vessels a tubular structure carrying blood through the tissues and organs; a vein, artery, or capillary. Blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. As the atrium contracts, blood flows from your right atrium into your right ventricle through the open tricuspid valve.