Blood vessels may be tiny but they cover a lot of ground. Show
The smallest blood vessels measure only five micrometers. To give you some perspective, a strand of human hair measures about 17 micrometers. But if you took all the blood vessels out of an average child and laid them out in one line, the line would stretch over 60,000 miles. An adult’s would be closer to 100,000 miles long. There are three kinds of blood vessels: arteries, veins, and capillaries. Each of these plays a very specific role in the circulation process. Arteries carry oxygenated blood away from the heart. They’re tough on the outside but they contain a smooth interior layer of epithelial cells that allows blood to flow easily. Arteries also contain a strong, muscular middle layer that helps pump blood through the body. Capillaries connect the arteries to veins. The arteries deliver the oxygen-rich blood to the capillaries, where the actual exchange of oxygen and carbon dioxide occurs. The capillaries then deliver the waste-rich blood to the veins for transport back to the lungs and heart. Veins carry the blood back to the heart. They’re similar to arteries but not as strong or as thick. Unlike arteries, veins contain valves that ensure blood flows in only one direction. (Arteries don’t require valves because pressure from the heart is so strong that blood is only able to flow in one direction.) Valves also help blood travel back to the heart against the force of gravity.
Blood vessels circulate blood throughout your body. They help deliver oxygen to vital organs and tissues, and also remove waste products. Blood vessels include veins, arteries and capillaries.
Blood vessels are channels that carry blood throughout your body. They form a closed loop, like a circuit, that begins and ends at your heart. Together, the heart vessels and blood vessels form your circulatory system. Your body contains about 60,000 miles of blood vessels. There are three types of blood vessels:
How does blood flow through your body?Here’s how blood flows through your body:
The function of blood vessels is to deliver blood to the organs and tissues in your body. The blood supplies them with the oxygen and nutrients they need to function. Blood vessels also carry waste products and carbon dioxide away from your organs and tissues. Each type of blood vessel serves a different function:
There are blood vessels throughout your body. The main artery is your aorta, which connects to the left side of your heart. It runs down through your chest, diaphragm and abdomen, branching off in many areas. Near your pelvis, your aorta branches into two arteries that supply blood to your lower body and legs. The main vein in your body is the vena cava. The superior vena cava is in the upper right part of your chest. It carries blood from your head, neck, arms and chest back to your heart. The inferior vena cava is near the right side of your diaphragm. It brings blood from your legs, feet, abdomen and pelvis back to your heart. What do blood vessels look like?Blood vessels have a tube-like shape, but they rarely run in a straight line. Some are big enough to see under your skin. If you’ve ever had your blood drawn, you may have noticed veins on the inside of your arm. They might appear blue under your skin, even though your blood is red. How big are blood vessels?Some, like the aorta, have a wide diameter. For example, a normal aorta in the abdomen is about 2 centimeters wide (about the size of a nickel). But other blood vessels, such as capillaries, are extremely small. They range from 2 to 12 micrometers, which is even less than the diameter of a human hair. What are the blood vessels made of?Blood vessels have three layers of tissue:
A wide range of problems can affect your blood vessels, including:
How common are blood vessel disorders?Some blood vessel disorders are very common. For example, nearly half of all adults in the U.S. have high blood pressure. But others, such as vascular malformations, are rare. Less than 1% of the population develops this condition. Who gets blood vessel disorders?Your risk for vascular disease increases if you:
What are the symptoms of blood vessel disorders?Symptoms vary widely across the different types of blood vessel disorders. Some, such as aneurysms or vascular malformations, may not cause symptoms until a serious problem develops. In general, it’s a good idea to talk to your doctor if you experience:
How are blood vessel disorders diagnosed?Your healthcare provider may use a variety of tests to diagnose problems in your blood vessels, including: How are blood vessel disorders treated?Treatment for blood vessel disorders may include:
There are a variety of ways you can improve the health of your blood vessels, including:
Seek immediate medical attention if you experience:
A note from Cleveland Clinic Blood vessels carry blood from your heart to the rest of your body. They’re essential for making sure your organs and tissues get the oxygen and nutrients they need to work. But blood vessels can develop problems, such as blockages or enlargement. Severe blood vessel disorders can be life-threatening. You can keep your blood vessels in good shape by maintaining a healthy lifestyle.
Last reviewed by a Cleveland Clinic medical professional on 07/09/2021. References
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