All the vital functions of the human body, and all the psychological processes such as thinking, feeling and acting, would not exist if the circulatory system did not do its job. However, this part of the organism is not homogeneous, but is composed of different types of ducts, branches that cover almost all the body’s tissues and keep the cells alive by providing them with the oxygen and materials they need.

Next we will see the difference between arteries, veins and capillaries , and the way these small channels allow us to live.

The circulatory system

Although all cells in the human body work relatively autonomously, fulfilling their small role, they need the participation of something that goes beyond their own individuality. Not only do they need to be in a stable environment created by the surrounding membranes, but they also need a constant supply of oxygen and materials to maintain themselves in an operational mode.

The latter task is carried out, among other things, by the circulatory system. This consists of veins, arteries and capillaries, as well as the heart, the organ which helps to circulate the blood through the inner part of these organic conduits.

On the other hand, blood also acts as a channel of communication, not only serving to nourish cells. Specifically, it transports hormones from one side to the other, causing them to be received by their respective target organs in order to awaken a change in them: a contraction, the segregation of more hormones, the adoption of another form, etc.

The difference between arteries, capillaries and veins

The main differences between veins, capillaries and arteries (all parts of the circulatory system) are as follows.

1. Capillaries have no muscle walls

Capillaries are by far the thinnest of these three categories . On the other hand, their walls are not associated with muscle tissues.

2. Veins return to the heart, arteries leave the heart

Arteries are the first type of conduit through which blood passes after it passes through the heart. The veins, on the other hand, are the entry ways to the heart.

3. The capillaries serve as a “bridge”

The capillaries are located between the veins and the arteries . That is, they are branches that come out of the arteries and come back together to form veins.

4. Arteries maintain blood pressure

The arteries make the blood flow while maintaining the pressure inside the heart . Inside the veins, on the other hand, this pressure is not present, and the same is true for the capillaries.

5. In capillaries there is an exchange of substances, in veins and arteries, no

The capillaries, besides being the narrowest conduits, also have very thin walls , ideal for certain substances to pass through. This is exactly what happens: there are particles that leave the blood to reach target cells, and others enter the bloodstream through them.

In this way, the cells obtain the necessary resources to live and, on the other hand, hormones can enter the blood and navigate it until they reach their destination.

6. Arteries regain their shape when crushed, veins and capillaries do not

The walls of the arteries are thicker than those of the rest of the ducts of the nervous system, and easily retain their shape .

7. Veins carry unoxygenated blood, the other two carry oxygen

Since it is their turn to return to the heart, the blood carried by the veins has already lost its oxygen on the way , and must therefore be carried back to the lungs to the areas occupied by the alveoli.

8. Veins have valves

As the blood that goes through the veins is not subjected to the pressure generated by the heart’s impulse, it is carried to its destination by a system of valves that prevent this fluid from going in the opposite direction to where it should go.

Conclusion

Although these types of ducts are similar in the most basic way, they do not have the same properties or perform the same function. Whether by their shape, by their parts or by the role they play in the circulatory system, they are easy to distinguish both in image and live, working on their tasks.

However, it should be noted that an injury, for example, does not have the same impact if it occurs in an artery, vein or capillary. The latter are the most dispensable, as they are so narrow that they are usually beyond the reach of human sight, and their breakage as a whole will produce bruising, but usually not much more . On the other hand, a cut in the other two can be fatal.