The main difference between lumen of artery and vein is that the lumen of an artery is comparatively smaller than the lumen of a vein.
Blood vessels are one of the structural components of the blood circulatory system. They are the channels that carry blood throughout the body. They branch and combine together to form a closed circuit that begins and ends in the heart. There are about 60000 miles of blood vessels in your body. Mainly there are three types of blood vessels: arteries, veins, and capillaries. The lumen of a blood vessel refers to the inside cavity of the blood vessels.
Key Areas Covered
1. What is the Lumen of Artery
– Definition, Structure, Features
2. What is the Lumen of Vein
– Definition, Structure, Features
3. Difference Between Lumen of Artery and Vein
– Comparison of Key Differences
Key Terms
Lumen of Artery, Lumen of Vein
What is the Lumen of Artery
The lumen of an artery is the hollow passage that is inside an artery. Through the lumen, the blood flows within the artery. The oxygenated blood, meaning oxygen-carrying blood, is transported via the lumens of arteries. Generally, the lumen of the artery carries blood away from the heart to the other organs and to the rest of the body. The pulmonary artery is an exception that carries deoxygenated blood from the heart to the lungs. The blood flow through the lumen is unidirectional.
Features of Lumens of Arteris
The lumen of the artery is comparatively smaller than that of the vein. This helps to build up and maintain the pressure inside the arteries, which is essential for the blood to flow inside. The walls that cover the lumen are also thicker than those of the arteries. This thickness in the artery walls helps to resist the pressure that is being built up when the blood flows through arteries. The smaller diameter and the thick wall give the lumen of arteries a rounder shape than that of the veins. Moreover, the lumen of the artery allows less blood to flow through the arteries with high resistance to pressure.
The lumen is covered by a wall that is more elastic. These walls are composed of living cells (endothelial cells), and their products include collagen and elastic fibers. They also produce waste products. These cells need nourishment. To supply nourishment and carry away waste products, there are blood vessels that supply blood to the artery wall called vasa vasorum. These blood vessels are located away from the lumen’s area, within the blood vessels (located in the outer area of the artery wall).
The size of the arterial lumen can vary depending on factors such as overall health, age, genetics, and lifestyle. A narrower lumen can even limit blood flow, which leads to reduced oxygen delivery to tissues and organs.
What is the Lumen of Vein
The lumen of a vein is the hollow cavity inside a vein. This lumen is larger than that of arteries. The blood flow through this lumen is unidirectional. The blood is carried from the various parts of the body to the heart through the lumens in the veins. The diameter of the lumens is higher than that of the arteries, and the wall covering the lumen is thinner than the wall coverings the arteries. Generally, the walls of the veins have special structures that project into the lumens called valves. These valves are present at particular distances from each other throughout the length of the vein. These valves prevent the backflow of blood.
The wall covering the lumen of the vein is less elastic than that in the arteries, and they have less smooth muscles and connective tissue. This makes the wall of the vein thinner. This is related to low blood pressure inside the lumen of the vein when compared to that of the arteries. The lumen of the vein holds more volume of blood than the lumen of arteries.
The size of the lumen also depends on the factors such as the size of the vein, the amount of blood flow, and the health of the veins. The lumen of veins can become narrow and obstructed due to various conditions such as inflammation, compression, and blood clots. These can lead to decreased blood flow through veins. But there are certain treatments for narrowing obstructed lumens of veins.
Difference Between Lumen of Artery and Vein
Definition
The lumen of an artery is the hollow cavity inside an artery, while the lumen of a vein is the hollow cavity inside a vein.
Size
The lumen of an artery is comparatively smaller than the lumen of a vein.
Constituents
Generally, the lumen of an artery carries oxygenated blood, whereas the lumen of a vein carries deoxygenated blood. However, the lumen of the pulmonary artery carries deoxygenated blood, and the lumen of the pulmonary veins carries oxygenated blood.
Presence of Valves
Lumens of arteries do not have valves, whereas lumens of veins have valves that prevent the backflow of blood.
Walls of the Lumen
Lumens of arteries have thick walls that are elastic, while lumens of veins have comparatively thin walls.
Conclusion
In brief, the lumens of arteries are comparatively smaller, have thicker walls that are elastic, and mainly carry oxygenated blood. On the other hand, lumens of veins are larger, have thinner walls, and mainly carry deoxygenated blood. Therefore, the main difference between lumen of artery and vein is their structure and function.
Reference:
1. “Lumen (anatomy).” Wikipedia. Wikipedia Foundation.
2. “Structure and Function of Blood Vessels.” Libre Text – Medicine.
Image Courtesy:
1. “Artery Vein Capillary Comparison” By Christinelmiller – Own work (CC BY-SA 4.0) via Commons Wikimedia
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