Picture of Aorta

The aorta is body's largest artery. It is approximately 12 inches long and about one inch in diameter. The aorta originates from the top of the left ventricle of the heart. Oxygenated blood from the heart leaves the left ventricle and travels into the aorta via the aortic valve. The valve contains three leaflets that allow for one-way blood flow through the vessel. The aorta has four main sections.

• The part of the aorta that arises from the left ventricle of the heart is called the ascending aorta. It is about 2 inches long. The coronary arteries that supply blood to the heart branch off of the ascending aorta.
• The next portion of the aorta is the aortic arch. It forms a curve above the heart. Vessels that supply blood to the neck, head, and arms originate from this part of the aorta.
• The portion of the aorta that is in the chest region is called the descending aorta. The vessels that branch off from this part of the aorta provide blood for the ribs and certain structures in the chest.
• The diaphragm marks the area of the body where the abdominal aorta begins. The vessel branches into the iliac arteries at the site of the lower abdomen. Blood vessels from the abdominal aorta feed the majority of the main organs of the body.

The wall of the aorta and other arteries are comprised of three layers:

• The inner, smooth layer of the aorta is called the intima.
• The middle layer of the aorta contains muscle and elastic fibers that confer flexibility to the vessel. This allows it to dilate and constrict as the heart beats. This middle layer is called the media.
• The outer portion of the aorta is called the adventitia. It serves to support and provide additional structure to the blood vessel.