What is the aorta?
The aorta is a cane-shaped artery. It starts in the lower-left chamber of your heart (ventricle). From there, it extends up toward your head a short distance before curving down. The aorta passes through your chest and abdominal cavities and ends at your pelvis.
Pairs of smaller blood vessels branch off from various points of the aorta. These branches extend the reach of the aorta to muscles, nerves and organs throughout your body.
How large is the aorta?
The aorta is the largest blood vessel in your body. It’s more than 1 foot long and an inch in diameter at its widest point. As the aorta makes its way toward your pelvis, its diameter narrows to two centimeters.
What is the aorta made of?
It’s a complex structure that has three layers of tissue. These include:
Inner layer (tunica intima): This is the tube through which blood passes. It contains smooth muscle tissue, connective tissue and endothelial cells. These special cells enable blood to transport oxygen and nutrients without getting absorbed until it reaches the right spot.
Middle layer (tunica media): This layer is made of smooth muscle tissue, elastin and collagen (proteins). These substances enable the aorta to meet your body’s changing blood flow needs. When more blood is necessary, the aorta widens. If less blood is needed, it narrows.
Outer layer (tunica adventitia): The outer layer anchors the aorta in place. It also connects to nearby nerves and tissue.
Function
What is the function of the aorta?
The aorta is the main vessel through which oxygen-rich blood travels from the heart to the rest of the body. It also delivers nutrients and hormones. The aorta’s branches ensure these substances reach internal organs and nearby supporting tissue.
Why is the aorta’s function so important?
The aorta is the primary source of oxygen and essential nutrients for many organs. If disease or injury affects blood flow through this vessel, life-threatening complications can occur in minutes. These include:
Aortic aneurysm.
Internal bleeding (hemorrhage).
Aortic dissection.
Kidney failure.
Stroke.
Anatomy
What is the anatomy of the aorta?
The aorta has many sections, including the:
Aortic root: Section that attaches to the heart. This is the widest part of the aorta.
Aortic valve: Three flaps of tissue (leaflets) that snap open and shut to release oxygen-rich blood from the heart.
Ascending aorta: Upward curve that occurs shortly after the aorta leaves the heart.
Aortic arch: Curved segment that gives the aorta its cane-like shape. It bridges the ascending and descending aorta.
Descending aorta: Long, straight segment that runs from your chest (thoracic aorta) to your abdominal area (abdominal aorta).
What are the aorta’s branches?
Many smaller blood vessels branch off from the aorta, including:
Ascending aortic branches
Coronary arteries supply blood to muscle tissue in your heart.
Aortic arch branches
Brachiocephalic trunk, which branches into the right subclavian artery (supplies the right arm) and right carotid artery (supplies the brain and right side of the head and neck).
Left subclavian artery supplies your left arm and the back of your brain.
Left carotid artery supplies your brain and the left side of the head and neck.
Descending thoracic aortic branches
Bronchial arteries supply the bronchioles, structures deep within the lungs.
Mediastinal arteries supply the mediastinum, a space between the lungs that houses the windpipe, esophagus and more.
Esophageal arteries supply the esophagus, a tube that connects the throat to the top of the stomach.
Pericardial arteries supply the pericardium, a protective sac that lubricates the heart.
Superior phrenic arteries supply the thoracic vertebrae, spinal cord and muscles, joints and skin of the middle back.
Descending abdominal aortic branches
Inferior phrenic arteries supply your diaphragm.
Celiac trunk arteries supply organs of your gastrointestinal system, including the stomach, liver, spleen and pancreas.
Superior and inferior mesenteric arteries supply your intestines.
Renal arteries supply your kidneys.
Gonadal arteries supply ovaries in women and testes in men.
Lumbar arteries supply the lumbar vertebrae, spinal cord, muscles, joints and skin of your lower back.
Median sacral arteries supply the lowest part of your spine (tailbone) and top of your pelvis.
Iliac arteries supply the lower extremities.