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Heart Health Center

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Human Anatomy

Picture of the Aorta

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 blood.

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 blood.
• 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 across.
• 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 the aorta.

Aorta Conditions

Aortic atherosclerosis: Cholesterol plaques build up in the wall of the aorta, posing a risk for stroke. High blood pressure and abnormal cholesterol levels are often responsible.
Aortic aneurysm: A weakness in the aorta's wall allows a section to expand like a balloon. Aortic aneurysms are slow to grow, but they can be fatal if they rupture.
Aortic dissection: High blood pressure and/or damage to the aorta's wall cause the wall's layers to separate. Aortic dissection can be life-threatening.
Aortic insufficiency: The aortic valve does not close completely, allowing some blood to flow back into heart with each beat. Autoimmune diseases, Marfan's syndrome, or endocarditis can cause aortic insufficiency.
Aortic regurgitation: Another name for aortic insufficiency. Blood regurgitates backward through the incompletely closed aortic valve and into the heart's left ventricle
Aortic stenosis: Narrowing of the aortic valve, which causes the heart to strain to pump blood through. Rheumatic fever is the most common cause of aortic stenosis, which can cause chest pain or shortness of breath.
Coarctation of the aorta: Narrowing of the aorta between its branches to the arms and those to the legs. This birth defect causes heart strain due to high blood pressure in the upper body.
Bicuspid aortic valve: 1% to 2% of people have an aortic valve with two leaflets instead of three. A bicuspid aortic valve can eventually lead to aortic insufficiency or aortic stenosis.
Aortitis: Inflammation of the aorta. Infections or autoimmune diseases are usually responsible.