Coronary Arteries and Heart Disease

Arteries are vessels that carry blood away from the heart. The coronary arteries are the first blood vessels that branch off from the ascending aorta. The aorta is the largest artery in the body. It transports and distributes oxygen-rich blood to all arteries. The coronary arteries extend from the aorta to the heart walls supplying blood to the atria, ventricles, and septum of the heart.

Coronary Arteries

The Heart and Coronary Arteries
The Heart and Coronary Arteries. Patrick J. Lynch, medical illustrator: Licenses

Coronary Arteries Function

The coronary arteries supply oxygenated and nutrient filled blood to the heart muscle. There are two main coronary arteries: the right coronary artery and left coronary artery. Other arteries diverge from these two main arteries and extend to the apex (bottom portion) of the heart.


Some of the arteries that extend from the main coronary arteries include:

  • Right Coronary Artery: Supplies oxygenated blood to the walls of the ventricles and the right atrium.
    • Posterior Descending Artery:  Supplies oxygenated blood to the inferior wall of the left ventricle and the inferior portion of the septum.
  • Left Main Coronary Artery:  Directs oxygenated blood to the left anterior descending artery and the left circumflex.
    • Left Anterior Descending Artery:  Supplies oxygenated blood to the anterior portion of the septum as well as to the walls of the ventricles and the left atrium (front region of the heart).
    • Left Circumflex Artery:  Supplies oxygenated blood to the walls of the ventricles and the left atrium (back region of the heart).

Coronary Artery Disease

Atherosclerosis in Coronary Artery
Colored Scanning Electron Micro- graph (SEM) of a cross-section through a human coronary artery of the heart showing atherosclerosis. Atherosclerosis is a build-up of fatty plaques on the walls of arteries. The artery wall is red; hyperplastic cells are pink; fatty plaque is yellow; lumen is blue.. GJLP/Science Photo Library/Getty Images

According to the Centers for Disease Control (CDC), coronary artery disease (CAD) is the number one cause of death for men and women in the United States. CAD is caused by the buildup of plaque on the inside of the artery walls. Plaque is formed when cholesterol and other substances accumulate in arteries causing the vessels to become narrow, thus restricting the flow of blood. The narrowing of vessels due to plaque deposits is called atherosclerosis. Since the arteries that become clogged in CAD supply blood to the heart itself, it means that the heart does not receive enough oxygen to function properly.

The symptom most commonly experienced due to CAD is angina. Angina is severe chest pain caused by a lack of oxygen supply to the heart. Another consequence of CAD is the development of a weakened heart muscle over time. When this occurs, the heart is not able to sufficiently pump blood to the cells and tissues of the body. This results in heart failure. If blood supply to the heart is completely cut off, heart attack can occur. A person with CAD may also experience arrhythmia, or an irregular heartbeat.

Treatment for CAD varies based upon the severity of the disease. In some cases, CAD may be treated with medication and dietary changes that focus on lowering blood cholesterol levels. In other cases, angioplasty may be done to widen the narrowed artery and increase blood flow. During angioplasty, a small balloon is inserted into the artery and the balloon is expanded to open the clogged area. A stent (metal or plastic tube) may be inserted in the artery after angioplasty to help the artery stay open. If a main artery or a number of different arteries are clogged, coronary bypass surgery may be required. In this procedure, a healthy vessel from another area of the body is relocated and connected to the blocked artery. This allows blood to bypass, or go around the blocked section of the artery to supply blood to the heart.