Artery vs Vein: Definition, Function, and Examples

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Artery vs Vein

Arteries and veins are two of the most common blood artery types in the cardiovascular system, which carries blood to all of the body’s cells. Arteries transport oxygenated blood from the heart to the rest of the body, whereas veins return deoxygenated blood to the heart.

Because the roles of veins and arteries are slightly different, there are some anatomical variations between the two. Arteries are designed to carry highly pressured blood, whereas veins contain characteristics that allow blood to flow in the opposite direction of gravity.

What is the Blood Circulatory System?

The heart and blood arteries make up the circulatory system (also known as the cardiovascular system). Its purpose is to convey blood throughout the body, giving nutrients and oxygen-rich blood to cells while removing deoxygenated blood and waste materials. The arteries and veins are two of the most common types of blood vessels in the human body.

What are Arteries?

One of the most common types of blood vessels in the human body are arteries. They are responsible for transporting oxygen-rich blood from the heart to the rest of the body. Except for the pulmonary artery, which delivers deoxygenated blood from the heart to the lungs, almost all of the arteries carry oxygenated blood.

The aorta is the biggest artery in the human body. When blood exits the heart, it passes via the aorta on its way to the rest of the body.

What are Veins?

Veins are blood channels that transport deoxygenated blood back to the heart from the body. Although it generally carries deoxygenated blood, the pulmonary vein returns oxygenated blood from the lungs to the heart.

The inferior vena cava is the biggest vein in the human body. This blood artery carries deoxygenated blood back to the heart from the lower body.

Artery vs Veins

Arteries and veins are both important parts of the circulatory system, and they both carry blood across the body. There are, however, a few important distinctions between the two.

1. Arteries carry blood away from the heart, while veins carry blood back to the heart.

2. Arteries transport blood under high pressure while veins transport blood under low pressure.

3. Arteries carry oxygenated blood (exception: pulmonary artery), while veins carry deoxygenated blood (exception: pulmonary vein).

4. Arteries have thick, muscular walls containing lots of elastin, but veins have thinner walls containing less elastin.

5. Arteries have no valves while veins have valves.

6. Artery has a smaller lumen but veins have a larger lumen.

Direction of Blood Flow

Blood is carried out from the heart by arteries, while blood is returned to the heart via veins. Almost all arteries convey oxygenated blood, while almost all veins transport deoxygenated blood.

The pulmonary artery (which transports deoxygenated blood from the heart to the lungs) and the pulmonary vein are the sole exceptions to this rule (which carries oxygenated blood from the lungs to the heart).

Adaptations to Blood Pressure

Blood in the arteries is subjected to significantly higher pressure than blood in the veins. This is because the heart’s pumping action ‘squeezes’ the blood, putting it under tremendous pressure. Because the aorta is directly linked to the heart, blood pressure is very high there.

Arteries have a number of structural modifications that help them withstand this strain, the most notable of which is their thick, muscular walls. The artery walls are significantly thicker and more elastic than the vein walls, which aren’t required to be as robust or long-lasting.

As blood flows through the artery walls, their flexibility permits them to bulge outwards, preventing them from bursting. The blood pressure steadily falls as it goes away from the heart.

It is under low pressure by the time it reaches the veins. As a result, the veins’ walls are much thinner and less elastic than the arteries. Arteries and veins both have lower lumens.

This aids in maintaining blood pressure and keeping it flowing through the cardiovascular system. A bigger lumen in a vein makes transporting blood at low pressure and against gravity simpler and more efficient.

Presence of Valves

Valves, which are found in the heart and veins but not in the arteries, are another important distinction in the construction of various blood vessels. Valves are elastic tissue flaps that open and close, functioning as gates to prevent blood from flowing backward.

They aren’t required in the arteries since the blood pressure is too high for backflow to occur. They are, nevertheless, required in veins, where blood is under considerably lower pressure and must travel against gravity (for example, from the feet back up to the heart).

What are Capillaries?

Capillaries are the third most common kind of blood vessel in the human body. They link smaller arteries (called arterioles) to smaller veins and are the tiniest and most numerous types of blood vessels in the body (called venules).

Capillaries allow blood to come into intimate contact with bodily tissues, and their primary purpose is to transport oxygen and nutrients to cells while removing carbon dioxide and waste. Because the capillary walls are so thin – only one cell thick – molecules can readily diffuse across them.

Artery vs Vein Citations
  • Radial artery graft vs. saphenous vein graft for coronary artery bypass surgery : which conduit offers better efficacy? Herz . 2014 Jun;39(4):458-65.
  • A systematic review of vascular closure devices for femoral artery puncture sites. J Vasc Surg . 2018 Sep;68(3):887-899.
  • Saphenous vein graft vs. radial artery graft searching for the best second coronary artery bypass graft. J Saudi Heart Assoc . 2013 Oct;25(4):247-54. 
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