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.

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).