At first glance, the name of this organ is strange, because the bone marrow does not have the functions of the brain. Nevertheless, the name is completely logical formally: just as the brain of the brain is surrounded by the bones of the skull, so the bone marrow is also “hidden” in the solid. 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 as small as it seems to most people - as much as 4% of the mass, which means that in the body of an average person (70 kg) it will amount to 2.8 kg by weight - quite a lot.
There are two types of bone marrow. Strictly speaking, one of these types cannot be considered an organ, although it makes up a certain proportion of the mass of 2.8 kg. We are talking about bone marrow yellow. These are actually fat cells. And there is another species that histologists collectively consider as a separate organ, because it is occupied by the mysterious function of hematopoiesis.
Why did we use the word "mysterious"? The fact is that blood is directly actively formed from mysterious stem cells. And they are very unusual. Judge for yourselves: an ordinary cell can divide only fifteen times, but stem cells do not have such a restriction, as cancer cells do not. Maybe this is why oncological diseases of the red bone marrow are so common?
Up to half a billion new blood cells are formed here per day, it is not surprising that the mass of this organ is quite large. The red bone marrow is very well equipped with blood vessels, through which, as a kind of water supply, 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. From here come the cells of three types: white row, red and platelet. Erythrocytes, which are “preoccupied” with oxygen transfer, are obtained from red, leukocyte defenders (including lymphocytes) from white, and cells responsible for blood coagulation, which help the body in blood loss situations, from platelets.
Not all immune cells circulate in the body. A huge number of them for the time being is hidden in the bone marrow. In fact, there are 50 times more neutrophils (type of white blood cells) than in the blood, spleen and liver. This is a “special forces detachment”, which vigilantly protects us from intrusions of pathogens. They react instantly and leave the bone marrow first to attack the enemy. There they literally "devour" the enemy, this is called phagocytosis.
Before the birth of the baby, the liver knows the production of blood cells . However, hematopoietic processes (hematopoiesis) gradually fade there, and only the red bone marrow works day and night to create blood cells from stem cells. This body has no days off, if work slows down, this means that the body is in serious trouble and urgent measures must be taken to correct the situation. Therefore, severe blood diseases are treated so poorly. After all, bone marrow transplantation is not difficult - it is difficult to arrange so that it takes root. We know that this is a component of the immune system, and it is purely individual and inevitable conflict. Therefore, they try to transplant the bone marrow exclusively from the closest relatives.
At birth, most of the bone marrow is red; in an adult, half is already turned into yellow. But in exceptional cases, the body gives a command - and from the yellow bone marrow suddenly turns red again. How? This is a mystery - and it is 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.