The aorta is the biggest artery in the body, and it carries and distributes oxygen-rich blood to other arteries, says Regina Bailey on About Biology. It arises from the heart’s left ventricle, forms an arch and branches off into two smaller arteries in the abdomen.
The aorta’s walls have three layers, which are the tunica intima, the tunica media and the tunica adventitia, states Bailey. These layers consist of connective tissue and elastic fibers, which enable the aorta to stretch to avoid over-expansion because of the pressure exerted by blood flow on the walls.
The aorta is a tube that is 1 inch in diameter and around 1 foot in length, according to WebMD. It starts at the top of the left ventricle, which is the muscular pumping chamber of the heart. The heart pumps blood into the aorta via the aortic valve. The aortic valve has three leaflets which open and close with every heartbeat to allow one-way blood flow.
The ascending aorta, one of the aorta’s sections, rises up from the heart and is around 2 inches long, explains WebMD. The aortic arch gives rise to branches that carry blood to the neck, arms and head. The descending thoracic aorta has small branches that bring blood to the ribs and several chest structures, while the abdominal aorta supplies blood to most of the body’s major organs.