What is the human immune system? And why is it needed?

The human immune system is a collection of cells, tissues and organs that are responsible for providing protection against foreign microorganisms and substances, as well as their own cells, whose genetic program has been disrupted (eg, tumor cells). In the event that some damage or malfunction occurs in this system, it leads to the death of the whole organism.

Components of the human immune system

To date, the human immune system is represented as a combination of the following organs, tissues and cells:

1. Central lymphoid organs (lymphoid formations of the appendix, lymphoid formations of the large intestine, embryonic liver, bone marrow and thymus gland).
2. Peripheral lymphoid organs (spleen and lymph nodes).
3. Immunocompetent cells (monocytes, lymphocytes, polynucleated leukocytes, Langerhans cells and others).

In this case, all these cells, tissues and organs are important for the normal functioning of the immune system . Systems of organs (digestive, genitourinary and others) depend quite strongly on the level of immunity. In the event that it decreases, the risk of development of various infectious diseases, as well as the appearance of both benign and malignant tumors, increases by an order of magnitude. Consequently, the body's immune system plays a huge role for its normal functioning.

How does the human immune system work?

The immune response to the introduction of the microorganism is carried out by means of cells such as leukocytes. They come in several varieties: neutrophils (stab, segmented, basophils and eosinophils), monocytes and lymphocytes (B-lymphocytes, T-lymphocytes and NK-lymphocytes). It is the neutrophils that first reach the site of infection and start destroying foreign microorganisms. In doing so, they are better able to cope with bacteria. If the virus penetrates the body, then much more effective against them lymphocytes.

In addition to the fact that the human immune system is able to suppress most known microorganisms, it can still "remember" many of them and, in case of repeated infection, they cope with the trouble much faster (and with less loss for the body itself).

It is worth noting that the immune system, being very useful, can also have negative effects on the life of a person. This is most clearly manifested after organ transplantation. The fact is that due to the fact that immunity perceives tissues of the donor organ, as alien, often there is a reaction of rejection. As a result, people have to conduct complex studies and wait for a suitable donor for years. In addition, sometimes the woman's immune system suppresses the male spermatozoa, because, again, she begins to consider them alien and dangerous to the body. As a result, the so-called immunological incompatibility of partners is observed . To enable such a couple to have their own children, a woman must take immunosuppressive drugs. In the event that the mother's Rh factor is negative, and the fetus is positive, during the first pregnancy it can be immunized. As a result, the next child, if he is also a carrier of a positive Rh factor, can undergo a real attack from his mother's immune system, which leads to the development of quite severe conditions threatening both the fetus and the woman herself.