Arteries: Function, anatomy, and types - Medical News Today

Arteries are blood vessels. Most carry oxygen-rich blood away from the heart and deliver it to various organs and tissues. Arteries are a part of the circulatory system, along with the heart and other blood vessels.

The circulatory, or cardiovascular, system is essential for transporting blood around the body. It helps supply tissues with oxygen and nutrients and helps remove waste products.

Blood vessels are the channels in the body that distribute blood. The arterial system is a complex structure of vessels that carry blood away from the heart.

The blood in arteries is typically oxygenated. The exception is that the pulmonary artery instead delivers deoxygenated blood to the lungs, where it becomes oxygenated and returns to the heart via the pulmonary vein, before the heart distributes the blood to the rest of the body through the other arteries.

While arteries carry blood away from the heart, veins carry blood toward the heart. The arteries operate under higher pressure than other blood vessels, so they are typically thicker and more elastic.

In this article, we explore the anatomy, function, and types of arteries, as well as health conditions that affect them.

Arteries are elastic, muscular tubes. These blood vessels operate at a high pressure to help transport oxygen-rich blood away from the heart and deliver oxygen, nutrients, and hormones throughout the body.

Arteries branch repeatedly to form microscopic arteries, known as arterioles, to distribute blood into capillary beds. Capillaries are blood vessels that carry blood to the body's organs at a microscopic level.

Generally, an artery has three layers:

• Tunica intima: This innermost layer consists of elastic membranes and tissues that help the blood move in the right direction.
• Tunica media: This is the middle layer and the thickest. It comprises elastin and smooth muscle.
• Tunica adventitia: This outermost layer consists of collagen fibers and elastin, which provide added strength. This layer also enables arteries to expand and contract, an important feature for controlling blood pressure.

The body contains three main types of arteries:

• Elastic: These arteries contain more elastic than muscular tissue. The increased flexibility helps them accommodate surges of blood. Elastic arteries, including the pulmonary artery and aorta, come out of the heart.
• Muscular: These arteries contain less elastin and more smooth muscle fiber. The elastic arteries feed into muscular arteries, and the smooth muscle fibers allow them to expand and contract to control blood flow. Examples of these arteries are the coronary and femoral arteries.
• Arterioles: Arteries branch out and become smaller vessels called arterioles, which help distribute blood through networks of capillaries, which are microscopic.

When the heart beats, it moves blood through the circulatory system — the body's capillaries, veins, and arteries.

Arteries play a vital role. For example, the aorta is the largest and main artery. It carries blood away from the left ventricle of the heart to other parts of the body. This enables the supply of oxygen and other vital substances to organs, tissues, and cells.

After supplying oxygen to distant tissues, the blood that is now low in oxygen travels through capillaries and collects in systemic veins. It then returns to the heart via the right atrium, and the process repeats.

Among the network of arteries in the body are:

The aorta

The aorta is about an inch wide, making it the biggest artery in the body. Blood moves through the heart via the aortic valve, then the blood leaves the heart via the aorta. The other arteries branch out from there.

Head and neck arteries

Some examples include the right and left common carotid arteries, which are located in the neck. The external and internal carotid arteries branch off from the common carotids. The internal carotid supplies blood to the brain. The external carotid carries blood to the neck and lower face.

Torso arteries

One is the bronchial artery, which supplies blood to the lungs. Another is the pericardial artery, which carries blood to the membrane around the heart.

The posterior and superior intercostal arteries are pairs of arteries on both sides of the body that carry blood to areas of the torso, such as the skin, back, and spinal cord.

Abdomen arteries

One example is the celiac trunk, which supplies blood to the liver, spleen, and stomach. The superior and inferior mesenteric arteries carry blood to the intestines and the pancreas.

The inferior phrenic artery carries blood to the diaphragm. And the renal arteries carry blood to the kidneys. The lumbar arteries deliver blood to the spinal cord and vertebra.

Arm arteries

Arteries in the arm include the axillary, which travels from the torso to the arms. The brachial artery supplies blood to the upper part of the arm. The radial and ulnar arteries carry blood to the hand and wrist.

Leg arteries

Arteries in the leg include the femoral arteries, which carry blood to the thigh. The popliteal artery carries blood to the area below the knee. The tibial arteries supply blood to the feet and ankles.

Arteries and veins are both blood vessels, but they have different functions. Arteries carry oxygenated blood away from the heart and to the rest of the body. Veins do the opposite — they carry deoxygenated blood back to the heart.

Their anatomical structures are slightly different, too. The walls of the arteries are more elastic and thicker than those of veins. This is important because blood travels through the arteries at a higher pressure than it does through the veins.

Learn more about the differences between arteries and veins.

Various health conditions can affect the arteries. Some examples include:

Aortic aneurysm

An aortic aneurysm involves an area of bulging or weakness in the aorta. If the vessel bursts, it is often fatal.

The Centers for Disease Control and Prevention (CDC) report that a history of smoking accounts for about 75% of aneurysms that develop in the section of the aorta that runs through the abdomen.

Symptoms can include:

• sudden chest or back pain
• sudden and severe abdominal pain
• trouble breathing
• low blood pressure
• trouble swallowing

Coronary artery disease

Coronary artery disease (CAD) involves a buildup of plaque in the lining of the coronary arteries.

Plaque consists of deposits of cholesterols, and a buildup can narrow the space that the blood travels through. Eventually, the buildup of plaque can block blood flow to the heart, leading to a heart attack.

Symptoms of CAD include:

• chest pain
• dizziness
• cold sweats
• weakness

Peripheral artery disease

Peripheral artery disease (PAD) usually involves narrowing of the arteries that carry blood from the heart to the legs and feet. According to the American Heart Association, risk factors include smoking, type 2 diabetes, and older age.

Symptoms of PAD include:

• pain in the legs or hips
• leg fatigue
• trouble walking or climbing stairs
• sores in the feet or lower legs that do not heal

Pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) involves increased pressure in the arteries of the lungs. The arteries become narrowed and thick, which increases the pressure. This makes the heart work harder, and eventually, it can lead to heart failure.

According to the American Lung Association, up to 1,000 new cases of PAH develop in the country each year.

Symptoms of PAH include:

• shortness of breath
• chest pain
• fatigue
• swelling of the legs and feet

Learn more about health conditions that affect the circulatory system.

Arteries are a type of blood vessel. Most deliver oxygenated blood from the heart to the organs and tissues of the body. The largest artery is the aorta, which branches from the left ventricle of the heart.

Various health conditions can affect how well the arteries function, and some are severe. Anyone with symptoms of the conditions above should contact a healthcare professional.