The immune system - how it works?
Why during a flu epidemic, some people get sick and others - not?It was the same in the Middle Ages: the epidemic of especially dangerous infections - Plague Plague - whether justified reputation of "black death"? , smallpox, cholera Cholera: the main thing - to prevent dehydration kill someone, and someone left to live, because the country has not died out completely.So, people have something that protects them from the terrible danger?
What is the immune system
immune system - an association of organs and tissues, which protect the body from diseases by recognizing and destroying the invading external "outsiders" and their modified tumor cells.Destroys bacteria, viruses, protozoa, toxins own tumor cells, etc.All of them are foreign entities, or antigens.
The immune system consists of the thymus gland, bone marrow, embryonic (in utero), liver, intestines and lymphoid formations of the appendix (appendicitis), the lymph nodes, spleen, and also found in the blood and tissues of bone marrow-derived cells - lymphocytes, monocytes, andet al. Most of the cells of the immune system are constantly moving through the blood and lymph vessels in a section of the immune system and vice versa.
immune cells interact with each other and isolated environment diverse molecules that exert regulatory action against the body's own cells and the vast - for alien.Such molecules are called cytokines.
immune system to protect the body comes in stages.The first obstacle for the penetration of "outsiders" in the body are the physical barriers (skin, mucous membranes).If he managed to break through these barriers, the innate immune system is activated, which is aimed at all "enemies" in general rather than something concrete.Then turn on the acquired immune system, which developed at the first meeting with the data "violator" if the meeting takes place for the first time, the immune response is generated in the process of interaction with antigen.
cell (congenital) immunity
Cellular immunity is more ancient, mostly innate, but its members have acquired immunity and Immunity - the types and characteristics of children in adult .Protecting the body against "enemies" made by cells of the immune system.Such cells are called phagocytes, they destroy foreign particles by phagocytosis - ingestion and subsequent intracellular digestion.Another embodiment of phagocytes work (selection damaging particles in direct contact with the "enemy") occurs when the antigen is large (e.g. worms).
All phagocytes are divided into macrophages (granular leukocytes) and macrophages (monocytes).The first place to the appearance of "outsiders" rush macrophages, for them - macrophages.Attract them to the "scene of the battle" T-lymphocytes, which are allocated to this particular matter.Some phagocytic cells circulate throughout the body in search of penetrating into the body "outsiders."
humoral (acquired) immunity
humoral immunity - is the development of specific antibodies Antibodies - "soldiers' immunity to implement a particular antigen.Acquired immunity is improved in the course of human life.It provides a more pronounced immune response and an immunological memory, so that every foreign microorganisms is stored in the immune system and reintroducing it ready to meet the antibody.
immune system cells, which are responsible for the implementation of the key functions of the adaptive immune system are the lymphocytes (a type of white blood cells - white blood cells).They are divided into thymus-dependent (T-lymphocytes, which develop in the thymus) and thimic-independent (B lymphocytes - develop, passing the thymus in fetal liver).Lymphocytes bear on their surface molecules which recognize antigens.
T lymphocytes are divided into T helper (helper) and T-killrov (murderers).Helper T cells regulate the humoral immunity by activating B cells to produce antibodies specific proteins - cytokines and T-killer cells destroy the body's own cells (e.g., tumor) by allocating specific substances through direct contact.
B-lymphocyte function is primarily in the production of antibodies.The interaction of antibody with antigen, they stick together, which contributes complement (complex system of serum proteins).The complement system attacks foreign cells membrane.It includes more than 20 different proteins.Complement is a major component of the innate humoral immune response.Later complement destroys bacteria and viruses, and breakdown products are excreted
How the immune system remembers the meeting with the antigen
feature of the immune system lies in the fact that at a meeting with a specific antigen again, it "remembers" firstmeeting and produces antibodies to it, this ability is called immune memory.Immune memory provided T- and B-lymphocytes.
immune system - one of the most advanced mechanisms in our body.