Bone marrow: riddles are waiting for the researcher

At first glance, the name of this organ is strange, because the bone marrow does not possess the functions of the head. Yet the name is completely logically formal: how the brain of the head is surrounded by the bones of the skull, so the bone marrow is also "hidden" in a solid substance. Sometimes people do not have a very clear idea of the structure and functions of this formation. Let's try to fix this with this article.

The total mass of this organ hidden in the bones is not so small as it may seem to most people - as much as 4% of the mass, which means that in the body of the average person (70 kg) it will be 2.8 kg by weight - quite a lot.

Bone marrow is of two types. One of these types, strictly speaking, the body can not be considered, although it makes up a certain fraction of the mass of 2.8 kg. We're talking about the bone marrow yellow. In fact, these are fat cells. And there is another species that histologists collectively consider to be a separate organ, because it is occupied with the mysterious function of hemopoiesis.

Why did we use the word "mysterious"? The fact is that the blood directly is actively formed from the mysterious stem cells. And they are very unusual. Judge for yourself: an ordinary cell can only divide fifteen times, but there is no such restriction in stem cells, as there is no cancer cell. Maybe that's why so often there are oncological diseases of the red bone marrow?

On the day here up to half a billion new blood cells are formed, it is not surprising that the mass of this organ is large enough. The red bone marrow is very well supplied with blood vessels, along which, as in a kind of water pipe, new cells enter the general circulatory system. There is also one of the centers of the lymphatic system - an integral part of an effective immune system.

Of course, not only lymphocytes are formed in the red bone marrow. Hence, there are three types of cells: the white series, red and platelet. Red produces erythrocytes, "concerned" with the transfer of oxygen, from white - defenders-leukocytes (including lymphocytes), and from the platelet - cells responsible for clotting the blood, which help the body in situations of blood loss.

Not all immune cells circulate in the body. A huge number of them for the time being lurks in the bone marrow. In fact, there is 50 times more neutrophils (the type of leukocytes) than in the blood, spleen and liver. This is a "special task force", which vigilantly protects us from intrusions of pathogens. They react immediately and first leave the bone marrow to attack the enemy. There they literally "devour" the enemy, this is called phagocytosis.

Before the birth of a child, the product of blood cells is controlled by the liver. However, gradually blood-forming processes (hemopoiesis) are dying out there, and only the red bone marrow is working day and night to create blood cells from the stem. There are no days off for this body, if the braking of work occurs, this means that the body is in serious trouble and urgent measures must be applied to correct the situation. Therefore, severe blood diseases are treated so badly. After all, it is not difficult to transplant the bone marrow - it is difficult to arrange so that it can take root. We know that this is a component of the immune system, but it is purely individual and a conflict is inevitable. Therefore, they try to transplant the bone marrow exclusively from the closest relatives.

At birth, most of the bone marrow is red, in the adult half is already turned into yellow. But in exceptional cases, the body gives the command - and from the yellow bone marrow suddenly turns red again. How? It's a mystery - and it's waiting for its researchers. In general, the blood system, which includes the human bone marrow, is very complex and full of mysteries. The more discoveries are made, the more incomprehensible is revealed to us.