What is the difference between arteries, veins, and capillaries?

Book A Demo Class

A human body is a complex structure and blood flow is the primary aspect of a human body. Without the blood flow, there can be no human body as blood flow is necessary. Whether it be a human or an animal, blood flow is essential.

Veins, arteries, and capillaries are the three types of blood vessels and their major difference is marked by the roles they generally play in the circulation.

Taking the systemic circulation as a base example, let us understand the difference between all three terms.

Arteries

Arteries are the blood vessels that carry oxygenated blood to the tissues. An artery is basically a muscular tube that comprises three layers.

Arteries take the blood away from the heart. This refers to the oxygenated blood in the systemic circulation. So, arteries have to deal with a high pressure’s big pump that the heart generates with each beat.

Therefore, arteries need to have

Ample of elastic tissues to spring back to their original shape
Thick muscular walls
A thin lumen to keep pressure high enough to reach the tissues.

Capillaries

Capillaries are the tiniest blood vessels that serve as an association between the veins and arteries. The materials are generally exchanged between tissues and blood through capillaries. Its size generally ranges from 5 to 10 micrometers.

Capillaries have a cell wall that is known as endothelial walls that supports blood circulation.

The exchange of nutrients, water, and gases among the tissues and organs takes place in capillaries.

Continuing with the base example, from the arteries, the blood flows into the capillaries.

Capillaries are where the blood deposits oxygen into the tissues so that they can breathe. So in case, you think about how des the gas transport functions, they are required to have:

One cell thick and very thin walls
Requires a lot of capillaries to supply the tissues appropriately
Low pressure as the blood has spread from arteries to several capillaries.

Veins

Veins are the blood vessels that support blood circulation to the heart. It transports the oxygen and nutrients in the body. Also, water is provided to the cell through veins and veins carry back the deoxygenated blood from the several organs back to the heart.

Ultimately the deoxygenated blood flows into the veins to start its journey back to the heart.

As we know that capillaries comprise low blood pressure to pass to the veins so that the veins do not require thick walls just like arteries. But devoid of the high pressures to keep the blood moving, they require a way to keep the blood moving in the correct direction.

So the veins have

Thin walls
Large Lumen
Valves to stop the blood from going backward

Understanding the differences between Arteries, Capillaries, and Veins

Parameters	Arteries	Veins	Capillaries
Walls	Arteries have thick walls	Veins have thin walls	Capillaries have very thin walls
Function	This carries blood from the heart to different body parts	This carries blood from different body parts to the heart.	These blood vessels connect veins and arteries.
Valves inclusion	They do not have valves	They have valves and also prevents the blood backflow	They do not have valves
Blood carry function	All the arteries carry oxygenated blood except the pulmonary artery	All the veins carry deoxygenated blood except the pulmonary vein	Since capillaries connect veins and arteries, it comprises of both deoxygenated and oxygenated blood.
Types	There are three significant types of arteries namely arterioles, elastic arteries, and muscular arteries	There are three types of veins namely, pulmonary veins, superficial veins, and deep veins	There are three kinds of capillaries namely sinusoid capillaries, fenestrated capillaries, and continuous capillaries.
Layers	The outermost coat of arteries is thin whereas its middle layer is thick.	The outer layer of veins is thick while its middle layer is thin	There are no middle or outer layers in capillaries.
Total number	There are 27 major arteries in the human body	These stretch over 60000 to 100000 miles in a human body	There are 10 billion capillaries in a human body
Lumen size	The lumen of the artery is small	The lumen of veins is large	The lumen of capillaries is small.
Semi-lunar valves	There are no semilunar valves	Semilunar valves are present here	There are no semilunar valves
Blood pressure	The blood pressure is high in arteries	The blood pressure is low in the veins	The blood pressure is falling in capillaries
Blood flow	The blood flow here is rapid	The blood flow here is slow	The blood flow here is slow

Bottom Line!

We hope that this answer introduced you to significant differences between veins, arteries, and capillaries. These all are generally responsible for carrying blood circulation in a human body and ensures that the blood reaches every organ in the body.

Read More – Biology Questions

View More – Useful links for Your Child’s Development