Difference Between Artery and Vein (With Table)

Arteries and veins work together and maintain the blood flow. Although their functions are different, they are both parts of the circulatory system. The branches of arteries and veins are connected by capillaries. The cardiovascular system is encompassed with veins, arteries, and capillaries. The circulatory system nourishes the body with oxygen and nutrients.

Artery vs Vein

The difference between artery and vein is that they serve contrasting functions. Artery sends blood with sufficient oxygen. But the purpose of the vein is to dispatch blood with low oxygen to the heart. Veins accumulate all the oxygen-deficient blood and carry it back to the heart. These blood vessels are responsible for blood distribution. They are two closed tube systems that start and end at heart.

 The function of the artery is to transport blood away from the heart. Arteries are of three types according to their composition. Elastic arteries, also known as conducting arteries, are the first kind. They stretch concerning the pulse of the heart. The second type is muscular arteries that are middle-sized and function as a collector of blood from the elastic arteries. The last kind is arterioles. They are the smallest division of arteries and direct blood to the capillaries.

Veins get the deoxygenated blood back to the heart. When the blood traverse through the arteries, it loses oxygen. To oxygenate the blood, veins collect it and transport it. Veins lie close to the skin. Therefore, it is seen even with naked eyes. Such veins belong to the category of superficial veins. There are deeper veins as well.

Comparison Table Between Artery and Vein

Parameters of ComparisonArteryVein
FunctionCarries oxygenated blood from the heart to various cellsTransfers oxygen deficit blood to the heart from different cells
PressureHighLow
WallsRigidSoft
ValvesAbsentPresent
ColorRedBlue

What is Artery?

An artery is a part of the circulatory system. It is a blood vessel that carries mostly oxygenated blood from the heart and transports it into various parts of the body. The pulmonary artery is an exception in arteries. It transports deoxygenated blood. They are muscular elastic tubes that can transport blood even in high pressure with the pumping from the heart.

The largest artery in the human body is the aorta. It is connected to the heart’s left ventricle. It branches and forms arteries and capillaries. Arteries have layered walls. It has three layers constituted by an innermost lining, connective tissue, and elastic fibers. The arteries provide oxygen and nutrients to the different cells. They remove waste products like carbon dioxide. It is also responsible for maintaining blood pH.

There are two kinds of arteries: systemic arteries and pulmonary arteries. Systemic arteries are part of the cardiovascular system. They have two sub-divisions: muscular and elastic. This division is based on the composing muscles. The elasticity of the arteries increases with the increase in size. The systemic arteries transport blood to the arterioles and capillaries. Arterial damage happens when there is excessive blood pressure. The arteries adapt to varying pressures with the help of smooth muscles.

What is Vein?

Veins are blood vessels that perform the opposite function of arteries. They transport blood with a higher level of carbon dioxide to the heart. Valves are present in veins to assure there is no backflow of the deoxygenated blood. The pulmonary vein functions like an artery. Thus, it is an exception in the category of veins.

There are different types of classifications for veins. Veins are tube-like structures. They are translucent. The color of the veins in humans is generally blue due to the low level of oxygen. The largest veins are the venae cavae. There are two such veins: namely superior venae cavae and inferior venae cavae. The venous system includes these large veins and their sub-divisions.

Veins also have different layers and sub-layers. The division of veins into the pulmonary veins and systemic veins is based on the circuit in which the veins are found. The venous system is a low-pressure system. Muscle contractions determine the transport of blood. The deoxygenated blood is collected in the capillaries. The walls of the capillaries enable oxygen intake. The function of veins is to return blood to the heart. The majority of the blood volume is in the veins. 

Main Differences Between Artery and Vein

  1. Arteries transfer blood away from the heart. But veins dispatch blood to the heart.
  2. Oxygenated blood is transferred through most arteries. While deoxygenated blood is transported through veins.
  3. Blood flows in higher pressure in the arteries and low pressure in the veins.
  4. Arteries have thick muscular walls, but veins are thin-walled.
  5. Valves are present in veins but absent in arteries.
  6. Arteries appear in the color red. While veins have a blue color tone.
  7. The oxygen levels in arteries are higher than in veins. On the other hand, the levels of carbon dioxide are low in the artery but high in the vein.

Conclusion

Both arteries and veins are blood vessels, but they have varied functions. The structure of veins and arteries is different. There are only two kinds of arteries but four kinds of veins. Veins have valves to assure a unidirectional flow of blood. Arteries pump blood using the pressure of the heart. So, it is in one direction. But veins have to fight gravity, and hence, valves are necessary.

Disorders like angina pectoris affect the arteries. Veins are less prone to diseases like varicose veins. The direction of blood flow in arteries is downwards. Veins move the blood upward. Blood loss from arteries can be fatal as high pressure results in a rapid loss. Also, the expansion of the lumen in the artery is narrow but wide in vein.

References

  1. https://www.nejm.org/doi/full/10.1056/nejm200102083440607
  2. https://www.sciencedirect.com/science/article/pii/S0140673605718808
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