Aorta

From ArticleWorld

The aorta begins at the left ventricle of the heart and receives the blood that the ventricle pumps out. At the junction between the left ventricle and the aorta is the aortic valve, a one-way valve that prevents back flow of blood into the heart while it is at rest.

Anatomy

The aorta is the largest artery in the body. Initially, its course is upward, toward the head. This segment of the aorta is known as the “ascending aorta”. Within a short distance, it arches and takes a direct turn downward. The arched aspect of the aorta is called the “aortic arch” and the part of the aorta that is directed downward is called the “descending aorta”.

The aortic arch gives rise to three separate branches, the left common carotid artery, which goes to supply blood to the left side of the head, the brachiocephalic artery, which supplies blood to the right side of the head and to the right arm, and finally, the left subclavian artery that supplies blood to the left arm.

All functions of the aorta, past the three branches in the arch, involve supplying blood to the trunk and to the legs. For example, the aorta sends out branches to the bronchial tree in the lungs, to the muscles around the rib cage and to the arteries providing blood to the esophagus.

As soon as the downward-traveling aorta passes through the diaphragm, it is called the “abdominal aorta”. Every part of the aorta above the diaphragm is known as the “thoracic aorta”. In the abdomen, the aorta sends off major branches to the intestines, the liver and to both kidneys. The end of the aorta is near the pelvis, where it divides into two main branches, the common iliac arteries. These arteries provide all the circulation to the legs.

Diseases

A disease of the aorta can be something a child is born with or can be something that develops later in life. Babies can be born with a “coarctation” of the aorta, which is a narrowing near the arch of the aorta that prevents blood from getting through easily.

A child can be born with Marfan’s Syndrome, a genetic defect that affects the connective tissue throughout the body, including the tissue surrounding the aorta. These children can later develop a separation between the layers of the abdominal wall that can fill up with blood and block the lumen (center) of the aorta.

Some people can develop, usually beginning around age 50 years, a bulging of the aorta called an aortic aneurysm. Blood clots can form inside the bulge or the bulge can get so big that it ruptures the aorta. Similar to Marfan’s Syndrome, the aneurysm (or bulging) of the aorta can separate the different layers of the artery causing a “dissecting aortic aneurysm”. Conditions like this involving the aorta are usually extremely serious.