The Role of Arteries in the Circulatory System

Arteries are blood vessels that carry blood away from the heart to the rest of the body. They are shaped like tubes and branch into arterioles to reach the organs and tissues.

The pumping contractions of the heart propel the blood through all arteries in the body, beginning with the aorta, the main artery in the circulatory system.

This article explains the role of arteries in that system, as well as risks to the health of the arteries.

Arteries in Systemic Circulation

The main artery of the systemic circulation is the aorta. It is attached to the left ventricle of the heart and carries oxygenated blood.

The aorta branches into arteries of the body that go to different organs and body regions. You can feel your pulse in an artery, such as the carotid artery in the neck or the radial artery in the wrist.

The pulmonary artery differs from the others in that it is attached to the heart's right ventricle and carries blood that is poor in oxygen to the lungs. There, it branches into arterioles and capillaries so the blood can take on oxygen before returning to the heart via the pulmonary vein.

This oxygenated blood enters the left atrium of the heart, and is pumped to the left ventricle and out through the aorta.

Structure of Arteries

Arteries of the body contain a high percentage of a special type of muscle, called smooth muscle, that can be controlled by hormones and special signals from the nervous system.

The artery's structure includes:

• An outer layer made of collagen fibers
• A middle layer of smooth muscle and elastic fibers
• An inner layer called the endothelium

Blood travels through the hollow center of the arteries. If this hollow center becomes constricted due to muscle changes or the formation of plaques, it can raise blood pressure.

Plaque also makes the arteries less flexible. If an artery ruptures or is blocked, such as in a stroke or heart attack, the tissues that it normally supplies will die.

The thick, strong walls of arteries make them able to resist the high pressures that exist near the heart. All of the major organs in the body have their own special kind of arteries which are uniquely structured to deliver the supplies needed, including the heart itself.

What are the four major arteries of the heart?

The heart muscle is supplied by four coronary arteries. The left and right coronary arteries branch from the aorta. The left coronary artery further divides into the circumflex artery and the left anterior descending artery. These arteries may be replaced in coronary artery bypass graft (CABG) surgery. A quadruple bypass replaces all four.

Arterial Health

Hardening of the arteries is the common term for atherosclerosis and peripheral artery disease (PAD). This occurs when plaque forms from fat, cholesterol, calcium, protein, and inflammatory cells that narrow or block the arteries.

Risk factors for PAD include:

• Smoking
• Diabetes
• High blood pressure
• High cholesterol

PAD can lead to a number of serious health conditions, including:

• Heart attack
• Stroke
• Transient ischemic attack (TIA)
• Renal artery disease
• Amputation

When the same type of damage happens in the arteries of the heart, it is called coronary artery disease (CAD).

Frequently Asked Questions

The aorta pumps blood from the heart to the rest of the body, and may be considered the most important. Other arteries are critical to life and health, including carotid arteries that deliver oxygen to the brain. Conditions that affect the aorta are serious and should be discussed with your healthcare provider.

There are more than 20 major arteries in the body, such as the pulmonary artery delivering blood to the lungs and the femoral arteries that feed your lower extremities.

Lifestyle choices like diet and exercise, as well as limiting alcohol and avoiding tobacco use, may reduce your risk of arterial damage. Some researchers suggest these choices can limit up to 80% of all coronary artery disease.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

1. Cedars Sinai. Aortic Conditions, Diagnostics & Treatment.
2. Harvard T.H. Chan School of Public Health. Healthy Heart Score uses lifestyle behaviors to estimate cardiovascular disease risk.

• U.S. National Library of Medicine. How Does the Blood Circulatory System Work?

By Craig O. Weber, MD
Craig O. Weber, MD, is a board-certified occupational specialist who has practiced for over 36 years.

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