One of the most important tissues of our body is blood. It is she who is responsible for the supply of oxygen, that is, the nutrition of all cells, organs and systems. Therefore, it is extremely important to replenish the supplies of cells that form blood (red blood cells, platelets, white blood cells) in time.
The life span of each of these cells is quite small and ranges from 5 days (white blood cells) to 100 days (red blood cells). This entails the need for constant self-renewal of blood. The body has organs that perform this function.
Human blood-forming organs
The main structures of the body that perform the function of forming new blood cells include red bone marrow and spleen. The lymphatic system is also one of the parts for which the bone marrow works. Where is this organ and what is it, we consider below.
The location of the bone marrow in the body
The localization of the parts of the body that form the blood cells is quite pointed. The fact is that the main organs of blood formation - the red bone marrow and the spleen - are not identical in their functionality. So, it is the bone marrow that is the determining and basic in this matter, therefore its location, quantity and normal work for any human body is very important.
The main places of bone marrow localization are precisely the bones, but not all of them, since the red bone marrow contains only part of the bones, and the rest is yellow.
Structure development
The whole feature of the formation of bone marrow in humans is as follows:
- The bone marrow is laid and develops from the very beginning of embryonic embryo formation.
- At the stage of the embryo and then at the formed fetus, and also after birth for several years, all the bones of the body are the producers (producers) of blood cells and lymphocytes, that is, all of them are formed by the red bone marrow, where the bulk of young undifferentiated cells are located.
- Over time, it is replaced by yellow in the composition of all tubular large and small bones of the body.
Thus, it is already clear that the bone marrow can be of two forms: red and yellow.
Yellow bone marrow characterization
It is a fatty yellowish substance formed by cells produced by the body’s lipoid tissue. He does not take any part in the formation of blood or the formation of cellular structures of the immune system. In the course of life, it replaces the red brain in many bones, becoming an essential filler of the diaphysis of the tubular bones in old age. The total mass content in the body is approximately 2.5-3 kg. This is half of the total bone marrow mass. The main function is nutrition and elasticity of the bones. In addition, with large injuries and injuries, the yellow bone marrow can be temporarily replaced with red to restore normal blood circulation.
The structure of red bone marrow
Its main component is a large mass of undifferentiated and non-specialized cells called stem cells. This makes this structure unique and very important for human life. The structure of the bone marrow includes two main tissues: reticular (stroma) and hematopoietic.
The tissue from which all the elements of the internal composition of the red brain are formed is called the reticular stroma. It fills the entire internal space of the bones and contains the following elements:
- a large number of blood vessels, giving it a semi-liquid consistency and red color;
- fibroblast cells (producers of fibrin and fibrinogen)
- endothelial cells.
Along with reticular tissue in the red bone marrow, there are hematopoietic elements - stem cells. It is they who, in the process of differentiation and specialization, form red blood cells, lymphocytes, platelets and other blood and lymph components.
Thus, there are several places in the body that have bone marrow, where the main hematopoietic tissue is located - the red variety of the brain substance.
- Epiphases of short and long tubular bones.
- Diaphysis of tubular osteons.
- Flat bones.
- Vertebrae.
This location and localization is the norm for an adult.
Red bone marrow cells
Hematopoietic tissue contains a mass of stem cells that are close in composition and structure to embryonic, germinal. These are very important elements, because all the other cells of the body (and their billions) are highly specialized and can never replace other cells in tissues or re-specialize. But the stem can. Therefore, they are the base that gives rise to all the formed elements of the blood and part of the structures of the lymphatic system.
Bone marrow cells form five sprouts of hematopoiesis, each of which gives rise to one or another element.
- The erythrocyte sprout forms red blood cells - red blood cells that perform the main function of oxygen transport through organs and tissues.
- The granulocyte sprout forms eosinophils, neutrophils and basophils, which are important structures of the body’s immunity and also make up white blood cells.
- The lymphocyte germ gives rise to lymphocytes - the basis of the lymphatic system.
- A monocytic sprout forms monocytes - immune shaped elements.
- Megakaryocytic germ gives rise to platelet life - one of the main blood cells responsible for coagulation.
Thus, the functions of the red bone marrow will depend precisely on the structure of the cells that form it. All of them are vital structures. The disappearance of at least one type of element leads to severe human diseases requiring brain stem cell donation.
Bone marrow function
The special structure and purpose of the internal component of the flat bones determines their great importance for the body. In this regard, it is possible to determine several areas in which the bone marrow acts. Its functions are as follows:
- It is a continuous supplier of young, fresh blood cells, the renewal of which is necessary every day (red blood cells live for about a day, so millions of these structures die daily, and replacement is needed with new ones).
- They form a whole complex of structures opposing all foreign particles and bodies in the body, that is, they form the immune system.
- They control their own cellular elements and destroy unnecessary (for example, tumor).
- To the maximum limit the self-destruction of cells within the body, which can be caused by pathological processes.
Undoubtedly, bone marrow is invaluable. Where else is the structure capable of performing such important functions? Nowhere. There are no more analogues in the human body. This gives special significance and uniqueness to the red bone marrow of a person.
Spleen
In the beginning, we mentioned that not only bone marrow matters in the formation of blood. Yes, the direct formation of a large mass of its cells and the differentiation of stem cells are characteristic only for him. However, there are other hemopoietic organs that help the bone marrow in this function. The main one is the spleen. Consider its main functions:
- It is an erythrocyte depot of the body, if necessary (large blood loss, trauma, and so on) ejects a certain volume of these cells into the total blood mass.
- The spleen is a guard, a filter, through which a large mass of blood passes. It is it that neutralizes, eliminates foreign particles, and dissolves dead cells. She is an indispensable cleaner of our body.
- It forms monocytes - the structure of the heart tissue.
The spleen itself is small and weighs about 150 grams. It is located above the stomach, slightly to the left of it.
Transplantation
Unfortunately, life presents a person with such problems that it was generally considered impossible to get rid of for a long time. So, for example, until 1968, blood cancer was considered incurable. The same applies to such ailments as aplastic anemia, lymphoma, bone marrow disease. In these cases, medicine found the only way out - bone marrow transplantation. The procedure is quite young, complicated due to incomplete knowledge of the consequences and as yet not always proceeding without complications. But every year, such operations are becoming more common and simplified in execution.
Bone marrow transplantation can be of three types:
- Directly bone substance.
- Stem cells.
- Cord fluid (blood).
The choice of type depends on the type of disease. Today, all three varieties are widely used. The most important problem that specialists face is the selection of a donor for the operation. There are a number of indicators by which it should be suitable for the transplant to be successful both for him and for the recipient.
Donor selection
To find a suitable donor for transplantation of homeopoietic structures can be based on several conditions:
- coincidence in blood group (not always decisive, but very important);
- the absence in a person of diseases of a serious or chronic nature, as well as infectious diseases;
- the donor lacks mental disorders and hereditary ailments.
Most often, relatives: sisters, brothers, children or parents become excellent candidates for donation. But in this case, guaranteed tissue compatibility is observed only in 25 percent of cases. It is very difficult to determine the ideal source that a healthy bone marrow will give (a photo of how it looks can be found in the article). Therefore, you have to look for donors among strangers. Such people can be representatives of any nations, countries and races.
Types of bone marrow transplantation
There are two main types:
- autologous transplantation - when stem cells are taken from the patient in advance and are blocked in special conditions before surgery;
- allogeneic transplantation - the material is taken from donors, which include all suitable people, including relatives.
According to modern data, world leadership in the donor base is given to Germany and the United States. There are very few donors in Russia, which is why our patients are transplanted with stem cells from other nations.