What are white blood cells? Small defenders of the body

Being at a doctor's office, taking tests, you probably had to hear about leukocytes. Most people have a very superficial view of them, usually limited to knowing that they are contained in the blood and their number is high and low. It is clear that everyone wants to have everything in the body in the body, but what is the norm in this case? And in general, what is the leukocytes?

Let's understand. Human blood consists of plasma and contained in it in the suspended state of the smallest elements - leukocytes, erythrocytes and platelets. Leukocytes are colorless or so-called white blood cells, which fulfill the most important task of protecting the human body from all kinds of microorganisms and other foreign bodies, penetrating into the blood and tissues in different ways. Billions of these tiny defenders circulate through the body, as if bypassing his watch, being ready at any moment to join the fight against the aggressor.

In order to better imagine what leukocytes are and how they work, you can draw an analogy with the fighting. White blood cells - a kind of border guards or militiamen, which reveal the penetration of hostile elements into the protected territory and without delay enter into battle with them. If the size of the "saboteur" is small, the white blood cell captures it, absorbs it and exposes it to intracellular digestion. If the size of the foreign body is large for one defender, urgent mobilization is announced, detachments of leukocytes are pulled to the place of defeat, according to all the rules of military science, they take it in a ring and destroy it. This process of digesting foreign elements is called phagocytosis. But not everything is so simple - this is actually a fatal battle, because in it, leukocytes themselves die. The battlefield is dotted with the "bodies" of the destroyed enemies and the defenders themselves, from which a viscous liquid - pus is formed. Subsequently, they themselves leukocytes and bring order to the place of "slaughter".

Now that you have an idea of what leukocytes are, think for yourself - how much they need the body to reliably resist any external attack. Lots of! Normally, the number of leukocytes in one liter of blood varies between 4-9 billion. They become more in emergency cases, when the body is struggling with infections, purulent diseases, burns, or due to heavy bleeding. Such a process, when the number of white blood cells significantly increases, is called leukocytosis. He tells the doctor who reads the results of the tests that the body is struggling with the disease. But if the defenses are already running out, the immune system can not cope with outside calls, leukopenia begins - the reverse process, in which the number of small defenders is reduced. This result of the analysis is a warning: the patient is in serious condition, there is no recovery, the prognosis is unfavorable.

So, we know what leukocytes are and how their amount affects the patient's condition. But where do they come from, what kind of "factory" inside our body does the "defense order" do? The main supplier is the red bone marrow, in which there are special stem cells - from them the leukocytes are formed. You have probably heard about such a disease as leukemia. This is a pathological process in which stem cells die off massively. In this case, the white blood cells are not ripening, and in spite of the fact that they are formed by a large number, they can no longer perform their important functions. Therefore, with leukemia, bone marrow transplant operations are now increasingly being used to resume the process of producing full-fledged leukocytes.

However, there are also cases when it is leukocytes that can hinder the healing of a person. What are these cases? Transplantation of donor organs. Leukocytes have a conflict of the "own-alien" recognition system, and they attack the alien tissue fiercely, which can lead to rejection of the transplanted organ.