The aorta is the largest artery in the body. The aorta begins at the top of
the left ventricle, the heart's muscular pumping chamber. The heart pumps blood
from the left ventricle into the aorta through the aortic valve. Three leaflets
on the aortic valve open and close with each heartbeat to allow one-way flow of
The aorta is a tube about a foot long and just over an inch in diameter. The
aorta is divided into four sections:
• The ascending aorta rises up from the heart and is about 2 inches long. The
coronary arteries branch off the ascending aorta to supply the heart with
• The aortic arch curves over the heart, giving rise to branches that bring
blood to the head, neck, and arms.
• The descending thoracic aorta travels down through the chest. Its small
branches supply blood to the ribs and some chest structures.
• The abdominal aorta begins at the diaphragm, splitting to become the paired
iliac arteries in the lower abdomen. Most of the major organs receive blood
from branches of the abdominal aorta.
Like all arteries, the aorta's wall has several layers:
• The intima, the innermost layer, provides a smooth surface for blood to flow
• The media, the middle layer with muscle and elastic fibers, allows the aorta
to expand and contract with each heartbeat.
• The adventitia, the outer layer, provides additional support and structure to