Your circulatory system contains three blood vessel types: arteries, veins, and capillaries. Arteries carry blood from the heart, unlike veins, which carry blood to the heart.
According to the Cleveland Clinic, if you laid out all of the blood vessels in the circulatory system, they would be about 60,000 miles long!
Because arteries are moving blood being pumped out by the heart, the walls of arteries are thicker and more elastic than those of veins.
This is because the blood in the arteries passes through with a higher pressure than in veins. The thick, elastic walls of arteries accommodate that pressure.
Read on to discover more about the body’s network of arteries.
Arteries carry blood away from the heart in two distinct pathways:
- The systemic circuit. In this pathway, oxygen-rich blood is carried away from the heart and toward tissues of the body.
- The pulmonary circuit. In the pulmonary circuit, oxygen-depleted blood is carried away from the heart and into the lungs where it can acquire fresh oxygen and get rid of carbon dioxide.
Arteries can also be divided into elastic and muscular arteries based off of the material of their tunica media or middle layer.
- are closer to the heart where blood pressure is highest
- contain more elastic fibers, which allows them to both expand and contract with the surges of blood that occur when the heart beats
- are further from the heart where blood pressure is lower
- contain more smooth muscle tissue and less elastic fibers
Artery wall layers
The walls of arteries are three distinct layers:
- Tunica intima. The innermost layer that’s made up of cells called endothelial cells as well as elastic fibers.
- Tunica media. The middle, and often the thickest layer, that’s made up of smooth muscle cells and elastic fibers that can help control the diameter of the blood vessel.
- Tunica externa. The outermost layer that’s made up of elastic fibers and collagen. This layer predominantly provides structure and support.
Arteries come in a variety of sizes. The largest artery of the body is the aorta, which begins at the heart.
As they move further from the heart, arteries branch off and become increasingly smaller. The smallest arteries are called arterioles.
Arterioles connect to capillaries, which are the smallest blood vessels and are where the exchange of oxygen, nutrients, and waste occurs between the blood and the cells of the body.
After this exchange occurs, the blood enters the venous system, where it travels back toward the heart.
Below are some of the major arteries that are found in the body and the organs and tissues that they service.
The largest and most important artery in the circulatory system is the aorta. It’s so important because it serves as the initial pathway for blood that’s leaving the heart and going to the rest of the body via smaller, branching arteries.
Without the aorta, the body’s tissues wouldn’t get the oxygen and nutrients that they need.
The aorta is connected to your heart via the aortic valve. It’s formed of the following parts:
- Ascending aorta. The ascending aorta distributes oxygen and nutrients to the heart via the coronary arteries.
- Aortic arch. This has three major branches — the brachiocephalic trunk, the left common carotid artery, and the left subclavian artery. It sends blood to the upper body, including the head, neck, and arms.
- Descending aorta. The descending aorta sends blood to your torso, abdomen, and lower body. It’s referred to as the thoracic aorta above the diaphragm, but after passing the diaphragm, it becomes the abdominal aorta.
There are several head and neck arteries:
- Left and right common carotid. The left common carotid comes directly off the aortic arch, while the right common carotid comes from the brachiocephalic trunk.
- External carotid. These paired arteries are derived from the common carotid arteries. The external carotid supplies blood to areas like the face, lower jaw, and neck.
- Internal carotid. Like the external carotid, these paired arteries are also derived from the common carotid arteries. They’re the primary arteries supplying blood to the brain.
- Vertebral. Formed off of the subclavian arteries, these paired arteries travel up the neck, where they also supply blood to the brain.
- Thyrocervical trunk. Also derived from the subclavian arteries, the thyrocervical trunk branches into several vessels that send blood to the thyroid, neck, and upper back.
The torso arteries include:
- Bronchial. There are typically two bronchial arteries, one on the left and one on the right. They supply blood to the lungs.
- Esophageal. The esophageal artery provides blood to the esophagus.
- Pericardial. This artery supplies blood to the pericardium, which is a membrane that surrounds the heart.
- Intercostal. The intercostal arteries are a pair of arteries on either side of the body that send blood to various areas of the torso, including the vertebrae, spinal cord, back muscles, and skin.
- Superior phrenic. Like the intercostal arteries, the superior phrenic arteries are paired and deliver blood to the vertebrae, spinal cord, skin, and diaphragm.
The abdominal arteries include:
- Celiac trunk. Branching off from the abdominal aorta, the celiac trunk divides into smaller arteries that supply organs such as the stomach, liver, and spleen.
- Superior mesenteric. Also branching off of the abdominal aorta, it sends blood to the small intestine, pancreas, and most of the large intestine.
- Inferior mesenteric. Like the superior mesenteric artery, this artery also branches off of the abdominal aorta and supplies blood to the last portion of the large intestine, which includes the rectum.
- Inferior phrenic. These are paired arteries that supply blood to the diaphragm.
- Adrenal. The adrenal arteries are paired arteries that send blood to the adrenal glands.
- Renal. These paired arteries deliver blood to the kidneys.
- Lumbar. These paired arteries send blood to the vertebrae and spinal cord.
- Gonadal. The gonadal arteries are paired arteries that send blood to the testes in males and the ovaries in females.
- Common iliac. This branch of the abdominal aorta divides into the internal and external iliac arteries.
- Internal iliac. Derived from the common iliac artery, this artery supplies blood to the bladder, pelvis, and external portion of the genitals. It also supplies the uterus and vagina in females.
- External iliac. Also arising from the common iliac artery, this artery eventually becomes the femoral artery.
The arteries of the arm are the:
Leg arteries include:
- Femoral. Derived from the external iliac artery, this artery supplies blood to the thigh and divides into the various smaller arteries that supply the legs.
- Genicular. This supplies blood to the knee region.
- Popliteal. This is the name given to the femoral artery as it passes below the knee.
- Anterior and posterior tibial. Derived from the popliteal artery, these arteries supply blood to the lower portion of the leg. When they reach the ankle, they divide further to supply the ankle and foot region.
|Overall function||Transports blood away from the heart||Transports blood toward the heart|
|Pulmonary circulation||Moves oxygen-depleted blood from the heart to the lungs||Sends oxygen-rich blood from the lungs back to the heart|
|Systemic circulation||Delivers oxygen-rich blood from the heart to the body’s tissues||Returns oxygen-depleted blood back to the heart from the body’s tissues|
|Structure||Thick, elastic walls||Thin walls with valves to prevent backflow of blood|
|Examples of major vessels||Carotid artery, subclavian artery, bronchial artery, celiac trunk, superior/inferior mesenteric artery, femoral artery||Jugular vein, subclavian vein, bronchial vein, azygos vein, renal vein, femoral vein|
The arteries are blood vessels in the circulatory system that move blood away from the heart. This occurs through two different circuits.
The systemic circuit supplies the organs and tissues of the body with oxygen and other nutrients. The pulmonary circuit allows blood to acquire fresh oxygen while getting rid of carbon dioxide.
Because of their vital function, it’s important to keep arteries healthy. Damaged or narrowed arteries can lead to the body not getting an adequate blood supply, which can put you at risk for things such as heart attack or stroke.