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Immunity is an ability of a human body to get rid of alien bodies and to maintain thanks to it constancy of own fabrics, disposal, release from something or an organism sporotivlyaemost to invasions of alien microorganisms and infections, to support constant internal environment, and also to influence alien substances which possess antigenic properties. Immune responses can arise also on own cells which were changed in antigen the relation.
Immunity is implemented by special system of immunity which provides a human body homeostasis at the molecular and cellular levels of the organization.
From the biological point of view the sense of immunity consists in ensuring genetic integrity throughout organism life. Development of immune system gave the chance of existence of difficult organized organisms which are multicellular.
The conventional classification subdivides immunity into two look: acquired and inborn.
Artificial immunity happens active and passive. The first represents immunity which results from the postponed disease, and also after introduction of a vaccine. Passive artificial immunity can develop by transfer of antibodies with mother's colostrum to the newborn, a pre-natal way, at introduction in the form of serum of ready antibodies.
The congenital immunity is caused by molecular, cellular, physiological and anatomic features which are assigned to an organism hereditarily. Also such immunity is called constitutional, nonspecific. It found the last name due to the lack of specificity concerning antigens, and also lack of memory of primary contact with a pathogen. For example, not all people are are susceptible to tuberculosis, plague of dogs and even to HIV.
Also immunity can be artificial and natural.
The acquired immunity is formed after introduction of a vaccine or serum. At introduction of an inoculation takes place active artificial, and at administration of serum – a passive acquired immunity.
Natural immunity includes a congenital immunity, and also acquired as a result of a disease, and also a passive form which is created by transfer of antibodies from mother to the child.
Allocate peripheral and central bodies of immune system. The following concerns to the first:
- Lymph nodes
- Mestnoassotsiirovanny adenoid tissue: kishechnoassotsiirovanny, kozhnoassotsiirovanny, kozhnoassotsiirovanny.
Central bodies of immunity:
- Thymus gland
- Red marrow
Lymph nodes are bodies of immune system which are located along absorbent vessels. Each node possesses brain and cortical substance in which there are V-dependent and T-dependent sites.
The spleen is the zone body which is also relating to immune system. Besides, it bears in itself(himself) the depositing function concerning blood of the person. The surface of a spleen is covered with the capsule consisting of connecting fabric. It contains smooth muscle cells that allows a spleen to be reduced if necessary. In it there are also T - and V-dependent zones, macrophages. In immune system the spleen carries out the following functions:
- Phagocytosis of foreign debris
- Deposition of uniform elements of blood which already ripened
- Ensuring growth of lymphoid cells
- Control of destruction and condition of the damaged and old thrombocytes and erythrocytes
- Formation of macrophages from monocytes
The thymus gland is the central body of immunity in which there is a differentiation of lymphocytes from their predecessors who arrive from red marrow.
Red marrow is the body of an immunogenesis and hemopoiesis relating to the central bodies of immune system. It contains population of stem cells which is self-sustaining. To contain in red marrow T lymphocytes, also in it there is a differentiation from predecessors of V-lymphocytes.
Also immunocomponent cells are a part of immune system. All of them come from one parent cell of red marrow. Such cells are divided into agranulocytes and granulocytes. Basophiles, eosinophils, neutrophils concern to the last. Agranulocytes are lymphocytes and macrophages.
Basophiles make less than one percent from all granulocytes. Basophiles happen two forms – mast cells which are in fabric (along vessels, mucous, easy, etc. fabrics), and also actually basophiles which circulate in blood. Basophiles are capable to produce substances which stimulate an anaphylaxis – narrowing of bronchial tubes, reduction of unstriated muscles, vasodilatation. Besides, they interact with immunoglobulins. Thus, there is their participation in allergic reactions of a human body, namely, immediate type.
Eosinophils make from 2 to 5 percent in the general structure of granulocytes. They are capable to destroy and englobe microbes, however this function is not the main. Helminths are the main main thing of eosinophils. Helminths perish from osmotic shock when because of embedding in them special proteins a time is formed, and in cells of parasites water directs.
Neutrophils represent the short-lived and not sharing cells. They the most numerous – make 95 percent from the total amount of granulocytes. Various granules of neutrophils contain a large amount of antibiotic proteins which treat a liporeroksidaza, a lysozyme and other proteins. Such cells are capable to move independently to the place of localization of antigen thanking existence of motor reaction on chemical. Neutrophils stick to an endothelium of vessels, migrate to the location of antigens through a vascular wall. After that there is a fagotichesky cycle at which neutrophils are filled with products of an exchange, cells perish and turn into pus.
Monocytes are capable to turn in macrophages whom there are two look. One of them is an antigen-prezentiruyushchiye macrophages whose leading role consists in absorption of microbes and their subsequent representation to T lymphocytes. They take part at all stages of an immune response. Professional macrophages provide phagocytal protection against a microbic infection. Besides, they englobe some cells of an organism, and also a blood cell.
Some parts of a human body at emergence of alien antigens the immune response is not caused. Treat such bodies: placenta, embryo, seed plants, eyes and brain. Disturbance of such system can lead to development of autoimmune diseases. Besides, such diseases can develop because of damage of fabric barriers, unresponsiveness. For example, pathological development of antibodies to receptors of own cells of muscles causes a myasthenia.