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Human immune system presentation. About the organs of the immune system

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Human immune system

The immune system is a collection of organs, tissues and cells, the work of which is aimed directly at protecting the body from various diseases and to destroy foreign substances that have already entered the body. This system is an obstacle to infections (bacterial, viral, fungal). When at work immune system failure occurs, the likelihood of developing infections increases, this also leads to the development autoimmune diseases. Organs included in the human immune system: lymph glands (nodes), tonsils, thymus gland, Bone marrow, spleen and intestinal lymphoid formations (Peyer's patches). Plays the main role a complex system circulation, which consists of lymphatic ducts connecting the lymph nodes. 1. WHAT IS THE IMMUNE SYSTEM

2. INDICATORS OF WEAK IMMUNITY The main sign of a weak immune system is constant colds. For example, the appearance of herpes on the lips can be safely considered a signal of a violation of the body's defenses. Also symptoms of a weakened immune system are fatigue, increased drowsiness, constant feeling of tiredness, aching joints and muscles, insomnia, and allergies. Moreover, the presence chronic diseases also speaks of weak immunity.

3. INDICATORS OF STRONG IMMUNITY A person does not get sick and is resistant to the effects of germs and viruses even during viral infections.

4. WHAT HELP STRENGTHEN THE IMMUNE SYSTEM diet. physical activity. a correct understanding of life, which means you need to learn not to envy, not to get angry, not to get upset, especially over trifles. observe sanitary and hygienic standards, do not overcool, do not overheat. harden the body both through cold procedures and through thermal ones (bath, sauna). saturate the body with vitamins.

5. CAN A PERSON LIVE WITHOUT AN IMMUNE SYSTEM? Any disorder of the immune system has a destructive effect on the body. For example, allergies. The body of an allergy sufferer reacts painfully to external irritants. It could be an eaten strawberry or an orange swirling in the air. Poplar fluff or pollen from alder catkins. The person begins to sneeze, his eyes water, and a rash appears on his skin. This increased sensitivity is an obvious malfunction of the immune system. Today, doctors are increasingly talking about weak immunity, and that 60% of our country’s population suffers from immune deficiency. Weakened by stress and bad environment the body is not able to effectively fight infection - too few antibodies are produced in it. Man with weak immunity gets tired quickly, it is he who first gets sick during a flu epidemic and gets sick longer and more severely. They call it the “plague of the 20th century” terrible disease, which affects the body's immune system - AIDS (acquired immunodeficiency syndrome). If there is a virus in the blood - the causative agent of AIDS, then there are almost no lymphocytes in it. Such an organism loses the ability to fight for itself, and a person may die from a common cold. The worst thing is that this disease is infectious, and it is transmitted through blood.

SOURCES OF INFORMATION http://www.ayzdorov.ru/ttermini_immynnaya_sistema.php http://www.vesberdsk.ru/articles/read/18750 https://ru.wikipedia http://gazeta.aif.ru/online/kids /99/de01_02 2015

On the topic: methodological developments, presentations and notes

Presentation "Human respiratory system. Diseases of the respiratory system"

This presentation is a good visual material for biology lessons in 8th grade on the topic " Respiratory system person"...

Presentation "Human respiratory system"

This presentation is a visual material for biology lessons in grade 8 on the topic “Human Respiratory System”...

ORGANS OF THE IMMUNE SYSTEM ARE DIVIDED INTO CENTRAL AND PERIPHERAL. THE CENTRAL (PRIMARY) ORGANS OF THE IMMUNE SYSTEM INCLUDE THE BONE MARROW AND THE THYMUS. IN THE CENTRAL ORGANS OF THE IMMUNE SYSTEM MATURATION AND DIFFERENTIATION OF IMMUNE SYSTEM CELLS FROM STEM CELLS OCCUR. IN THE PERIPHERAL (SECONDARY) ORGANS THE MATURATION OF LYMPHOID CELLS OCCURS TO THE FINAL STAGE OF DIFFERENTIATION. THESE INCLUDE THE SLEEN, LYMPH NODES AND LYMPHOID TISSUE OF THE MUCOUS MEMBRANES.

CENTRAL ORGANS OF THE IMMUNE SYSTEM Bone marrow. All the formed elements of blood are formed here. Hematopoietic tissue is represented by cylindrical accumulations around arterioles. Forms cords that are separated from each other by venous sinuses. The latter flow into the central sinusoid. The cells in the cords are arranged in islands. Stem cells are localized mainly in the peripheral part of the bone marrow canal. As they mature, they move toward the center, where they penetrate the sinusoids and then enter the blood. Myeloid cells in the bone marrow account for 60-65% of cells. Lymphoid 10-15%. 60% of cells are immature cells. The rest are mature or newly entered into the bone marrow. Every day, about 200 million cells migrate from the bone marrow to the periphery, which is 50% of their total number. In the human bone marrow, intensive maturation of all types of cells occurs, except for T cells. The latter pass only initial stages differentiation (pro-T cells, then migrating to the thymus). Plasma cells are also found here, constituting up to 2% of the total number of cells, and producing antibodies.

T IMUS. C SPECIALIZES EXCLUSIVELY ON THE DEVELOPMENT OF T-LYMPHOCYTES. AND HAS AN EPITHELIAL FRAMEWORK IN WHICH T-LYMPHOCYTES DEVELOP. IMATURE T-LYMPHOCYTES THAT DEVELOP IN THE THYMUS ARE CALLED THYMOCYTES. MATURATING T-LYMPHOCYTES ARE TRANSIT CELLS THAT ENTER THE THYMUS IN THE FORM OF EARLY PREcursors FROM THE BONE MARROW (PR-T-CELLS) AND AFTER MATURATION, EMIGRATE TO THE PERIPHERAL DEPARTMENT OF THE IMMUNE SYSTEM. THREE MAIN EVENTS OCCURRING IN THE PROCESS OF T-CELL MATURATION IN THE THYMUS: 1. APPEARANCE OF ANTIGEN-RECOGNIZING T-CELL RECEPTORS IN MATURING THYMOCYTES. 2. DIFFERENTATION OF T-CELLS INTO SUB-POPULATIONS (CD4 AND CD8). 3. ABOUT SELECTION (SELECTION) OF T-LYMPHOCYTE CLONES CAPABLE OF RECOGNIZING ONLY ALIEN ANTIGENS PRESENTED TO T-CELLS BY MOLECULES OF THE MAIN HISTO COMPATIBILITY COMPLEX OF THEIR OWN ORGANISM. THE HUMAN TIMUS CONSISTS OF TWO LOBES. EACH OF THEM IS LIMITED BY A CAPSULE, FROM WHICH CONNECTIVE FABRIC SEPARATIONS GO INSIDE. THE SEPTIA DIVIDE THE PERIPHERAL PART OF THE ORGAN CORTEX INTO LOBES. THE INTERNAL PART OF THE ORGAN IS CALLED THE BRAIN.

P ROTYMOCYTES ENTER THE CORTICAL LAYER AND AS THEY MATURATE, THEY MOVE TO THE MEDIUM LAYER. FROM THE DEVELOPMENT OF THYMOCYTES INTO MATURE T-CELLS IS 20 DAYS. IMMATURE T-CELLS ENTER THE THYMUS WITHOUT HAVING T-CELL MARKERS ON THE MEMBRANE: CD3, CD4, CD8, T-CELL RECEPTOR. AT THE EARLY STAGES OF MATURATION, ALL OF THE ABOVE MARKERS APPEAR ON THEIR MEMBRANE, THEN THE CELLS MULTIPLY AND PASS TWO STAGES OF SELECTION. 1. POSITIVE SELECTION SELECTION FOR THE ABILITY TO RECOGNIZE OWN MOLECULES OF THE MAIN HISTO COMPATIBILITY COMPLEX WITH THE HELP OF THE T-CELL RECEPTOR. CELLS THAT ARE NOT ABLE TO RECOGNIZE THEIR OWN MOLECULES OF THE MAIN HISTO COMPATIBILITY COMPLEX DIE BY APOPTOSIS (PROGRAMMED CELL DEATH). THE SURVIVED THYMOCYTES LOSE ONE OF THE FOUR T-CELL MARKERS OR THE CD4 OR CD8 MOLECULE. AS A RESULT, THE SO-CALLED “DOUBLE POSITIVE” (CD4 CD8) THYMOCYTES BECOME SINGLE POSITIVE. ON THEIR MEMBRANE EITHER THE CD4 OR THE CD8 MOLECULE IS EXPRESSED. THEREFORE, THE DIFFERENCES ARE ESTABLISHED BETWEEN THE TWO MAIN POPULATIONS OF T CELLS: CYTOTOXIC CD8 CELLS AND HELPER CD4 CELLS. 2. NEGATIVE SELECTION SELECTION OF CELLS FOR THEIR ABILITY TO NOT RECOGNIZE THE ORGANISM’S OWN ANTIGENS. AT THIS STAGE, POTENTIAL AUTOREACTIVE CELLS ARE ELIMINATED, THAT IS, CELLS WHOSE RECEPTOR IS CAPABLE OF RECOGNIZING ANTIGENS OF THEIR OWN BODY. NEGATIVE SELECTION LAYS THE FOUNDATIONS FOR THE FORMATION OF TOLERANCE, THAT IS, THE IMMUNE SYSTEM’S IMMUNE RESPONSES TO ITS OWN ANTIGENS. AFTER TWO STAGES OF SELECTION, ONLY 2% OF THYMOCYTES SURVIVE. THE SURVIVED THYMOCYTES MIGRATE TO THE MEDUAL LAYER AND THEN LEAVE INTO THE BLOOD, TURNING INTO “NAIVE” T-LYMPHOCYTES.

P PERIPHERAL LYMPHOID ORGANS Scattered throughout the body. The main function of peripheral lymphoid organs is the activation of naive T- and B-lymphocytes with the subsequent formation of effector lymphocytes. There are encapsulated peripheral organs of the immune system (spleen and lymph nodes) and non-encapsulated lymphoid organs and tissues.

L LYMPHATIC NODES CONSTITUTE THE MAIN MASS OF ORGANIZED LYMPHOID TISSUE. THEY ARE REGIONALLY LOCATED AND ARE NAMED ACCORDING TO THE LOCATION (AXILLARY, INGUINAL, PAROTICAL, ETC.). L LYMPHATIC NODES PROTECT THE BODY FROM ANTIGENS THAT PENETRATE THROUGH THE SKIN AND MUCOUS MEMBRANES. H CARRONS ANTIGENS ARE TRANSPORTED TO THE REGIONAL LYMPH NODES THROUGH LYMPHATIC VESSELS, OR WITH THE HELP OF SPECIALIZED ANTIGEN PRESENTING CELLS, OR WITH THE FLOW OF FLUID. IN THE LYMPH NODES, ANTIGENS ARE PRESENTED TO NAIVE T-LYMPHOCYTES BY PROFESSIONAL ANTIGEN-PRESENTING CELLS. THE RESULT OF THE INTERACTION OF T-CELLS AND ANTIGEN-PRESENTING CELLS IS THE CONVERSION OF NAIVE T-LYMPHOCYTES INTO MATURE EFFECTOR CELLS CAPABLE OF PERFORMING PROTECTIVE FUNCTIONS. L LYMPH NODES HAVE A B-CELL CORTICAL AREA (CORTICAL ZONE), a T-CELL PARACORTICAL AREA (ZONE) AND A CENTRAL, MEDULLARY (BRAIN) ZONE FORMED BY CELL TRADS CONTAINING T-I B-LYMPHOCYTES, PLASMA CELLS AND MACROPHAGES. THE ORCAL AND PARACORTICAL AREAS ARE DIVIDED BY CONNECTIVE TISSUE TRABECULES INTO RADIAL SECTORS.

L LYMPH ENTERS THE NODE THROUGH SEVERAL AFFERENT LYMPHATIC VESSELS THROUGH THE SUBCAPSULAR ZONE COVERING THE CORTICAL AREA. AND FROM THE LYMPH NODE, LYMPH EXITS THROUGH A SINGLE OUTFERING (EFFERENT) LYMPHATIC VESSEL IN THE AREA OF THE SO-CALLED GATE. THROUGH THE GATE THROUGH THE CORRESPONDING VESSELS, BLOOD ENTERS AND OUTSIDE THE LYMPH NODE. IN THE CORTICAL REGION ARE LOCATED LYMPHOID FOLLICLES, CONTAINING MULTIPLICATION CENTERS, OR “GERMINAL CENTERS,” IN WHICH THE MATURATION OF B CELLS THAT ENCOUNTER THE ANTIGEN OCCURS.

THE PROCESS OF MATURATION IS CALLED AFFINE MATURATION. O N IS ACCOMPANIED BY SOMATIC HYPERMUTATIONS OF VARIABLE IMMUNOGLOBULIN GENES, OCCURING WITH A FREQUENCY 10 TIMES EXCEEDING THE FREQUENCY OF SPONTANEOUS MUTATIONS. C OMATIC HYPERMUTATIONS RESULT IN AN INCREASE IN THE AFFINITY OF ANTIBODIES WITH THE SUBSEQUENT REPRODUCTION AND CONVERSION OF B CELLS INTO PLASMA ANTIBODY PRODUCING CELLS. P PLASMIC CELLS ARE THE FINAL STAGE OF B-LYMPHOCYTE MATURATION. T-LYMPHOCYTES ARE LOCALIZED IN THE PARACORTICAL AREA. E E IS CALLED T-DEPENDENT. THE T-DEPENDENT AREA CONTAINS MANY T-CELLS AND CELLS WITH MULTIPLE PROGRESSES (DENDRITIC INTERDIGITAL CELLS). THESE CELLS ARE ANTIGEN-PRESENTING CELLS THAT ARRIVED INTO THE LYMPH NODE THROUGH THE AFFERENT LYMPHATIC VESSELS AFTER MEETING WITH A FOREIGN ANTIGEN AT THE PERIPHERY. NIVE T-LYMPHOCYTES, IN THEIR TURN, ENTER THE LYMPH NODES WITH THE LYMPH CURRENT AND THROUGH POST-CAPILLARY VENULES, HAVING AREAS OF THE SO-CALLED HIGH ENDOTHELIUM. IN THE T-CELL AREA, NAIVE T-LYMPHOCYTES ARE ACTIVATED WITH THE HELP OF ANTI-GEN-PRESENTING DENDRITIC CELLS. AND ACTIVATION RESULTS IN PROLIFERATION AND FORMATION OF CLONES OF EFFECTOR T-LYMPHOCYTES, WHICH ARE ALSO CALLED REINFORCED T-CELLS. THE LATTER ARE THE FINAL STAGE OF MATURATION AND DIFFERENTIATION OF T-LYMPHOCYTES. THEY LEAVE THE LYMPH NODES TO PERFORM EFFECTIVE FUNCTIONS FOR WHICH WERE PROGRAMMED BY ALL PREVIOUS DEVELOPMENT.

THE LENE IS A LARGE LYMPHOID ORGAN, DIFFERENT FROM THE LYMPH NODES BY THE PRESENCE OF A LARGE NUMBER OF RED CYTES. THE MAIN IMMUNOLOGICAL FUNCTION IS THE ACCUMULATION OF ANTIGENS BROUGHT WITH THE BLOOD AND THE ACTIVATION OF T- AND B-LYMPHOCYTES REACTING TO THE ANTIGEN BROUGHT BY THE BLOOD. THE SPLEN HAS TWO MAIN TYPES OF TISSUE: THE WHITE PULP AND THE RED PULP. THE WHITE PULP CONSISTS OF LYMPHOID TISSUE, WHICH FORMES PERIARTERIOLARY LYMPHOID COUPLINGS AROUND THE ARTERIOLES. THE CLUTCHES HAVE T- AND B-CELL AREAS. A T-DEPENDENT AREA OF THE CLUTCH, SIMILAR TO THE T-DEPENDENT AREA OF LYMPH NODES, DIRECTLY SURROUNDS THE ARTERIOLE. B-CELL FOLLICLES CONSTITUTE THE B-CELL REGION AND ARE LOCATED CLOSE TO THE EDGE OF THE MOUNT. THERE ARE REPRODUCTION CENTERS IN THE FOLLICLES, SIMILAR TO THE GERMINAL CENTERS OF LYMPH NODES. IN THE CENTERS OF REPRODUCTION, DENDRITIC CELLS AND MACROPHAGES ARE LOCALIZED, PRESENTING ANTIGEN TO B-CELLS WITH THE SUBSEQUENT CONVERSION OF THE LATTER INTO PLASMA CELLS. MATURATING PLASMA CELLS PASS THROUGH VASCULAR LINKERS INTO THE RED PULP. THE RED PULP IS A cellular network FORMED BY VENOUS SINUSOIDS, CELLULAR TRADS AND FILLED WITH ERYTHROCYTES, PLATELETS, MACROPHAGES, AND OTHER CELLS OF THE IMMUNE SYSTEM. THE RED PULP IS A SITE OF DEPOSITATION OF erythrocytes and platelets. THE APPILLARIES WITH WHICH END THE CENTRAL ARTERIOLES OF THE WHITE PULP OPEN FREELY IN BOTH THE WHITE PULP AND IN THE RED PULP TRADS. WHEN THE BLOOD LEAKS REACH THE HEAVY RED PULP, THEY ARE RESTAINED IN THEM. HERE MACROPHAGES RECOGNIZE AND PHAGOCYTE SURVIVED erythrocytes and platelets. PLASMIC CELLS, MOVED INTO THE WHITE PULP, CARRY OUT THE SYNTHESIS OF IMMUNOGLOBULINS. BLOOD CELLS NOT ABSORBED AND NOT DESTROYED BY PHAGOCYTES PASS THROUGH THE EPITHELIAL LINING OF VENOUS SINUSOIDS AND RETURN TO THE BLOOD STREAM TOGETHER WITH PROTEINS AND OTHER PLASMA COMPONENTS.

N ENCAPSULATED LYMPHOID TISSUE Most of the unencapsulated lymphoid tissue is located in the mucous membranes. In addition, non-encapsulated lymphoid tissue is localized in the skin and other tissues. Lymphoid tissue of the mucous membranes protects only the mucous surfaces. This distinguishes it from the lymph nodes, which protect against antigens that penetrate both the mucous membranes and the skin. The main effector mechanism of local immunity at the mucosal level is the production and transport of secretory antibodies IgA class directly onto the surface of the epithelium. Most often, foreign antigens enter the body through the mucous membranes. In this regard, antibodies of the IgA class are produced in the body in the greatest quantities relative to antibodies of other isotypes (up to 3 g per day). The lymphoid tissue of the mucous membranes includes: Lymphoid organs and formations associated with gastrointestinal tract(GALT gut-associated lymphoid tissues). Includes lymphoid organs of the peripharyngeal ring (tonsils, adenoids), appendix, Peyer's patches, intraepithelial lymphocytes of the intestinal mucosa. Lymphoid tissue associated with bronchi and bronchioles (BALT bronchial-associated lymphoid tissue), as well as intraepithelial lymphocytes of the mucous membrane respiratory tract. Lymphoid tissue of other mucous membranes (MALT mucosal associated lymphoid tissue), including as the main component the lymphoid tissue of the mucous membrane of the urogenital tract. Lymphoid tissue of the mucosa is most often localized in the basal plate of the mucous membranes (lamina propria) and in the submucosa. An example of mucosal lymphoid tissue is Peyer's patches, which are usually found in the lower part ileum. Each plaque is adjacent to a portion of the intestinal epithelium called follicle-associated epithelium. This area contains so-called M cells. Bacteria and other foreign antigens enter the subepithelial layer from the intestinal lumen through M cells. THE BASIC MASS OF LYMPHOCYTES IN PEYER'S PATCH ARE IN THE B-CELL FOLLICLE WITH A GERMAL CENTER IN THE MIDDLE. T-CELL ZONES SURROUND THE FOLLICLE CLOSE TO THE LAYER OF EPITHELIAL CELLS. THE MAIN FUNCTIONAL LOAD OF PEYER'S PATCHES IS THE ACTIVATION OF B-LYMPHOCYTES AND THEIR DIFFERENTIATION INTO PLASMA CYTES PRODUCING ANTIBODIES OF CLASSES I G A AND I G E. IN ADDITION TO ORGANIZED LYMPHOID TISSUE IN THE EPITHELIAL LAYER OF THE MUCOSA X AND IN LAMINA PROPRIA THERE ARE ALSO SINGLE DISSEMINATED T-LYMPHOCYTES. THEY CONTAIN BOTH ΑΒ T-CELL RECEPTOR AND ΓΔ T-CELL RECEPTOR. IN ADDITION TO LYMPHOID TISSUE OF MUCOSAL SURFACES, NON-ENCAPSULATED LYMPHOID TISSUE INCLUDES: SKIN-ASSOCIATED LYMPHOID TISSUE AND SKIN INTRAEPITHELIAL LYMPHOCYTES; LYMPH, TRANSPORTING FOREIGN ANTIGENS AND CELLS OF THE IMMUNE SYSTEM; PERIPHERAL BLOOD, UNITING ALL ORGANS AND TISSUE AND PERFORMING A TRANSPORT AND COMMUNICATION FUNCTION; CLUMPS OF LYMPHOID CELLS AND SINGLE LYMPHOID CELLS OF OTHER ORGANS AND TISSUE. AN EXAMPLE COULD BE LIVER LYMPHOCYTES. THE LIVER PERFORMES QUITE IMPORTANT IMMUNOLOGICAL FUNCTIONS, ALTHOUGH IT IS NOT CONSIDERED AN ORGAN OF THE IMMUNE SYSTEM FOR AN ADULT BODY. HOWEVER, ALMOST HALF OF THE TISSUE MACROPHAGES OF THE ORGANISM ARE LOCALIZED IN IT. THEY PHAGOCYTATE AND DISSOLVE IMMUNE COMPLEXES, WHICH BRING RED CELLS HERE ON THEIR SURFACE. IN ADDITION, IT IS ASSUMED THAT LYMPHOCYTES LOCALIZED IN THE LIVER AND IN THE INTESTINAL SUBMUCOSA HAVE SUPRESSOR FUNCTIONS AND PROVIDE CONSTANT MAINTENANCE OF IMMUNOLOGICAL TOLERANCE (UNRESPONDENCE) TO FOOD.

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The main role in anti-infective protection is played not by immunity, but by various mechanisms of mechanical removal of microorganisms (clearance). In the respiratory organs, this is the production of surfactant and sputum, the movement of mucus due to the movements of the cilia of the ciliary epithelium, coughing and sneezing. In the intestines, this is peristalsis and the production of juices and mucus (diarrhea due to infection, etc.) On the skin, this is constant desquamation and renewal of the epithelium. The immune system turns on when the clearance mechanisms fail.

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Ciliary epithelium

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Barrier functions of the skin

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Thus, in order to survive in the host’s body, the microbe must “fix” on the epithelial surface (immunologists and microbiologists call this adhesion, that is, gluing). The body must prevent adhesion using clearance mechanisms. If adhesion occurs, the microbe may try to penetrate deep into the tissue or into the bloodstream, where clearance mechanisms do not work. For these purposes, microbes produce enzymes that destroy host tissues. All pathogenic microorganisms differ from non-pathogenic microorganisms in their ability to produce such enzymes

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If one or another clearance mechanism fails to cope with the infection, then the immune system joins in the fight.

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Specific and nonspecific immune protection

Specific defense refers to specialized lymphocytes that can fight only one antigen. Nonspecific immune factors, such as phagocytes, natural killer cells and complement (special enzymes) can fight infection either independently or in cooperation with specific defense.

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Complement system

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The immune system consists of: immune cells, a number of humoral factors, immune organs ( thymus gland, spleen, lymph nodes), as well as accumulations of lymphoid tissue (most massively represented in the respiratory and digestive organs).

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The immune organs communicate with each other and with body tissues through lymphatic vessels and the circulatory system.

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There are four main types of pathological conditions of the immune system: 1. hypersensitivity reactions, manifested in the form of immune tissue damage; 2. autoimmune diseases, developing as a result immune reactions against one's own body; 3. immune deficiency syndromes resulting from congenital or acquired defects in the immune response; 4. amyloidosis.

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HYPERSENSITIVITY REACTIONS Contact of the body with an antigen not only ensures the development of a protective immune response, but can also lead to reactions that damage tissue. Such hypersensitivity reactions (immune tissue damage) can be initiated by the interaction of an antigen with an antibody or cellular immune mechanisms. These reactions can be associated not only with exogenous, but also with endogenous antigens.

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Hypersensitivity diseases are classified based on the immunological mechanisms that cause them. Classification There are four types of hypersensitivity reactions: Type I - the immune response is accompanied by the release of vasoactive and spasmogenic substances. Type II - antibodies are involved in cell damage, making them susceptible to phagocytosis or lysis. Type III - the interaction of antibodies with antigens leads to the formation of immune complexes that activate complement. Complement fractions attract neutrophils, which damage tissue; Type IV - a cellular immune response develops with the participation of sensitized lymphocytes.

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Type I hypersensitivity reactions (immediate type, allergic type) can be local or systemic. A systemic reaction develops in response to intravenous administration antigen to which the host organism is previously sensitized and may have the character anaphylactic shock.Local reactions depend on the site of penetration of the antigen and have the character of limited swelling of the skin ( skin allergy, urticaria), nasal and conjunctival discharge ( allergic rhinitis, conjunctivitis), hay fever, bronchial asthma or allergic gastroenteritis (food allergy).

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Hives

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Type I hypersensitivity reactions go through two phases in their development - the initial response and the late one: - The initial response phase develops 5-30 minutes after contact with the allergen and is characterized by vasodilation, increased permeability, as well as spasm of smooth muscles or gland secretion.- Late phase observed after 2-8 hours without additional contact with the antigen, lasts several days and is characterized by intense tissue infiltration by eosinophils, neutrophils, basophils and monocytes, as well as damage to epithelial cells of the mucous membranes. The development of type I hypersensitivity is ensured by IgE antibodies formed in response to an allergen with the participation of T2 helper cells.

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Type I hypersensitivity reaction underlies the development of anaphylactic shock. Systemic anaphylaxis occurs after the administration of heterologous proteins - antisera, hormones, enzymes, polysaccharides, and some drugs (for example, penicillin).

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Type II hypersensitivity reactions (immediate hypersensitivity) is caused by IgG antibodies to exogenous antigens adsorbed on cells or the extracellular matrix. With such reactions, antibodies appear in the body directed against the cells of its own tissues. Antigenic determinants can be formed in cells as a result of disturbances at the gene level, leading to the synthesis of atypical proteins, or they represent an exogenous antigen adsorbed on the cell surface or extracellular matrix. In any case, a hypersensitivity reaction occurs as a consequence of the binding of antibodies to normal or damaged structures of the cell or extracellular matrix.

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Type III hypersensitivity reactions (an immediate hypersensitivity reaction caused by the interaction of IgG antibodies and a soluble exogenous antigen) The development of such reactions is due to the presence of antigen-antibody complexes formed as a result of the binding of antigen to antibody in the bloodstream (circulating immune complexes) or outside the vessels on the surface or inside cellular (or extracellular) structures (immune complexes in situ).

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Circulating immune complexes (CICs) cause damage when they enter the wall of blood vessels or filtering structures (the tubular filter in the kidneys). There are two known types of immune complex damage, which are formed when an exogenous antigen (foreign protein, bacteria, virus) enters the body and when antibodies are formed against one’s own antigens. Diseases caused by the presence of immune complexes can be generalized, if these complexes form in the blood and settle in many organs, or associated with individual organs, such as the kidneys (glomerulonephritis), joints (arthritis) or small blood vessels of the skin.

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Kidney with glomerulonephritis

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Systemic immune complex disease One of its varieties is acute serum sickness, which occurs as a result of passive immunization resulting from repeated administration of large doses of foreign serum.

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Chronic serum sickness develops with prolonged contact with an antigen. Constant antigenemia is necessary for the development of chronic immune complex disease, since immune complexes most often settle in the vascular bed. For example, systemic lupus erythematosus is associated with long-term persistence of autoantigens. Often, despite the presence of characteristic morphological changes and other signs indicating the development of an immune complex disease, the antigen remains unknown. Such phenomena are typical for rheumatoid arthritis, periarteritis nodosa, membranous nephropathy and some vasculitis.

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Systemic lupus erythematosus

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Rheumatoid polyarthritis

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Systemic vasculitis

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Local immune complex disease (Arthus reaction) is expressed in local tissue necrosis resulting from acute immune complex vasculitis.

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Delayed-type hypersensitivity (DTH) consists of several stages: 1 - primary contact with the antigen ensures the accumulation of specific T helper cells; 2 - upon repeated administration of the same antigen, it is captured by regional macrophages, which act as antigen-presenting cells, removing fragments antigen on its surface; 3 - antigen-specific T helper cells interact with antigen on the surface of macrophages and secrete a number of cytokines; 4 - secreted cytokines ensure the formation of an inflammatory response, accompanied by the accumulation of monocytes/macrophages, the products of which destroy nearby host cells.

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When the antigen persists, macrophages are transformed into epithelioid cells surrounded by a shaft of lymphocytes - a granuloma is formed. This inflammation is characteristic of type IV hypersensitivity and is called granulomatous.

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Histological picture of granulomas

Sarcoidosis Tuberculosis

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AUTOIMMUNE DISEASESDisorders immunological tolerance lead to a peculiar immunological reaction to the body’s own antigens - autoimmune aggression and the formation of a state of autoimmunity. Normally, autoantibodies can be found in the blood serum or tissues of many healthy people, especially in older age group. These antibodies are formed after tissue damage and play physiological role in removing its remains.

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There are three main signs of autoimmune diseases: - the presence of an autoimmune reaction; - the presence of clinical and experimental evidence that such a reaction is not secondary to tissue damage, but has a primary pathogenetic significance; - the absence of other specific causes of the disease.

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At the same time, there are conditions in which the action of autoantibodies is directed against one’s own organ or tissue, resulting in local tissue damage. For example, in Hashimoto's thyroiditis (Hashimoto's goiter), antibodies are absolutely specific for thyroid gland. In systemic lupus erythematosus, a variety of autoantibodies react with components nuclei of various cells, and in Goodpasture syndrome, antibodies against the basement membrane of the lungs and kidneys cause damage only in these organs. Obviously, autoimmunity implies a loss of self-tolerance. Immunological tolerance is a condition in which an immune response to a specific antigen does not develop.

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IMMUNE DEFICIENCY SYNDROMESimmunological deficiency (immunodeficiency) - pathological condition, caused by a deficiency of components, factors or links of the immune system with inevitable violations of immune surveillance and/or immune response to a foreign antigen.

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All immunodeficiencies are divided into primary (almost always determined genetically) and secondary (associated with complications infectious diseases, metabolic disorders, side effects immunosuppression, radiation, chemotherapy for cancer). Primary immunodeficiencies are a heterogeneous group of congenital, genetically determined diseases caused by impaired differentiation and maturation of T and B lymphocytes.

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According to WHO, there are more than 70 primary immunodeficiencies. Although most immunodeficiencies are quite rare, some (such as IgA deficiency) are quite common, especially in children.

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Acquired (secondary) immunodeficiencies If immunodeficiency becomes the main cause of the development of a persistent or often recurrent infectious or tumor process, we can talk about secondary immune deficiency syndrome (secondary immunodeficiency).

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Acquired immunodeficiency syndrome (AIDS)By the beginning of the 21st century. AIDS is registered in more than 165 countries around the world, and the largest number of people infected with the human immunodeficiency virus (HIV) is in Africa and Asia. Among adults, 5 risk groups have been identified: - homosexual and bisexual men make up the largest group (up to 60% of patients); - persons who inject drugs intravenously (up to 23%); - patients with hemophilia (1%); - recipients of blood and its components (2%); - heterosexual contacts between members of other groups increased risk, mainly drug addicts - (6%). In approximately 6% of cases, risk factors are not identified. About 2% of AIDS patients are children.

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EtiologyThe causative agent of AIDS is the human immunodeficiency virus, a retrovirus of the lentivirus family. There are two genetically different shapes virus: human immunodeficiency viruses 1 and 2 (HIV-1 and HIV-2, or HIV-1 and HIV-2). HIV-1 is the most common type, found in the USA, Europe, Central Africa, and HIV-2 - mainly in West Africa.

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Pathogenesis There are two main targets for HIV: the immune system and the central nervous system. The immunopathogenesis of AIDS is characterized by the development of deep immunosuppression, which is mainly associated with a pronounced decrease in the number of CD4 T cells. There is a lot of evidence that the CD4 molecule is actually a high-affinity receptor for HIV. This explains the selective tropism of the virus for CD4 T cells.

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The course of AIDS consists of three phases, reflecting the dynamics of interaction between the virus and the host: - the early acute phase, - the middle chronic phase, - and the final crisis phase.

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Acute phase. The initial response of the immunocompetent individual to the virus develops. This phase is characterized high level formation of the virus, viremia and widespread contamination of lymphoid tissue, but the infection is still controlled by an antiviral immune response. The chronic phase is a period of relative containment of the virus, when the immune system is intact, but weak replication of the virus is observed, mainly in the lymphoid tissue. This phase can last several years. The final phase is characterized by a violation defense mechanisms host and uncontrolled viral replication. The content of CD4 T cells decreases. After an unstable period, serious opportunistic infections, tumors appear, and the nervous system is affected.

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The number of CD4 lymphocytes and virus RNA copies in the patient’s blood from the moment of infection to terminal stage. CD4+ T lymphocyte count (cells/mm³) Number of viral RNA copies per ml. plasma

Epidemics of plague, cholera, smallpox, and influenza left a deep mark on the history of mankind. In the 14th century, a terrible epidemic of the “Black Death” swept through Europe, killing 15 million people. It was a plague that swept through all countries and killed 100 million people. She left an equally terrible mark behind. smallpox, called "black smallpox". The smallpox virus caused the death of 400 million people, and the survivors became permanently blind. 6 cholera epidemics have been registered, the last one in India and Bangladesh. The flu epidemic called “Spanish flu” has claimed the lives of hundreds of thousands of people over the years; there are known epidemics called “Asian”, “Hong Kong”, and today, “swine” flu.

Morbidity of the child population In the structure of the general morbidity of the child population over a number of years: in first place - diseases of the respiratory system; second place - occupied by diseases of the digestive system; in third place - diseases of the skin and subcutaneous tissue and diseases nervous system

Morbidity among children Statistical research In recent years, diseases associated with decreased immunity have been promoted to one of the first places in human pathology. Over the past 5 years, the level of general morbidity in children has increased by 12.9%. the largest increase was observed in the classes of diseases of the nervous system - by 48.1%, neoplasms - by 46.7%, pathologies of the circulatory system - by 43.7%, diseases of the musculoskeletal system - by 29.8%, endocrine system - by 26 .6%.

Immunity from lat. Immunities - liberation from something The immune system provides to the human body multi-stage protection against foreign invasions This is a specific protective reaction of the body, which is based on the ability to resist the action of living bodies and substances that differ from it in hereditarily foreign properties, to maintain its integrity and biological individuality. The main purpose of the immune system is to determine what is in the body and what is not someone else's. Your own must be left alone, and someone else’s must be destroyed, and as quickly as possible Immunity - ensures the functioning of the body as a single whole, consisting of one hundred trillion cells

Antigen - antibody All substances (microbes, viruses, dust particles, plant pollen, etc.) that enter the body from outside are usually called antigens. It is the influence of antigens that determines when they enter internal environment the body forms protein structures called antibodies. The main structural and functional unit of the immune system is the lymphocyte

Components of the human immune system 1. Central lymphoid organs: - thymus (thymus gland); - Bone marrow; 2. Peripheral lymphoid organs: - lymph nodes - spleen - tonsils - lymphoid formations of the colon, vermiform appendix, lungs, 3. Immunocompetent cells: - lymphocytes; - monocytes; - polynuclear leukocytes; - white branched epidermocytes of the skin (Langerhans cells);

Nonspecific factors of the body's defense The first protective barrier Nonspecific mechanisms of immunity are general factors and protective devices of the body Protective barriers The first protective barrier impermeability healthy skin and mucous membranes (gastrointestinal tract, respiratory tract, genital organs) impermeability of histohematological barriers presence of bactericidal substances in biological fluids(saliva, tears, blood, cerebrospinal fluid) and other secrets of sebaceous and sweat glands have a bactericidal effect against many infections

Nonspecific factors of the body's defense The second protective barrier The second protective barrier is inflammatory reaction at the site of introduction of the microorganism. The leading role in this process belongs to phagocytosis (a factor of cellular immunity). Phagocytosis is the absorption and enzymatic digestion of microbes or other particles by macro- and microphages, resulting in the liberation of the body from harmful foreign substances. Phagocytes are the largest cells of the human body, they perform important function nonspecific protection. Protects the body from any penetration into its internal environment. And this is its purpose, the phagocyte. The phagocyte reaction occurs in three stages: 1. Movement towards the target 2. Envelopment foreign body 3. Absorption and digestion (intracellular digestion)

Nonspecific body defense factors The third protective barrier operates when the infection spreads further. These are lymph nodes and blood (factors humoral immunity). Each of these factors of the three barriers and adaptations is directed against all microbes. Nonspecific protective factors neutralize even those substances that the body has not previously encountered

Specific mechanisms of immunity This is antibody formation in the lymph nodes, spleen, liver and bone marrow. Specific antibodies are produced by the body in response to the artificial introduction of an antigen or as a result of a natural encounter with a microorganism (infectious disease) Antigens are substances that carry a sign of foreignness (bacteria, proteins, viruses , toxins, cellular elements) Antigens are the pathogens themselves or their metabolic products (endotoxins) and bacterial breakdown products (exotoxins). Antibodies are proteins that can bind to antigens and neutralize them. They are strictly specific, i.e. act only against those microorganisms or toxins in response to the introduction of which they were developed.

Specific immunity It is divided into congenital and acquired. Innate immunity is inherent in a person from birth, inherited from parents. Immune substances from mother to fetus through the placenta. A special case of innate immunity can be considered the immunity received by a newborn with mother's milk Acquired immunity - occurs (acquired) during life and is divided into natural and artificial Natural acquired - occurs after suffering an infectious disease: after recovery, antibodies to the pathogen remain in the blood of this disease. Artificial - produced after special medical events and it can be active and passive

Artificial immunity Created by administering vaccines and serums Vaccines are preparations from microbial cells or their toxins, the use of which is called vaccination. 1-2 weeks after the administration of vaccines, antibodies appear in the human body. Serums are often used to treat infectious patients and, less often, to prevent infectious diseases.

Vaccinal prophylaxis This is the main practical purpose of vaccines Modern vaccine preparations are divided into 5 groups: 1. Vaccines from live pathogens 2. Vaccines from killed microbes 3. Chemical vaccines 4. Toxoids 5. Associated, i.e. combined (for example, DTP - associated pertussis-diphtheria-tetanus vaccine)

Serums Serums are prepared from the blood of people who have recovered from an infectious disease or by artificially infecting animals with microbes. The main types of sera: 1. Antitoxic sera neutralize microbial poisons (antidiphtheria, antitetanus, etc.) 2. Antimicrobial sera inactivate bacterial cells and viruses, are used against a number of diseases, more often in the form of gamma globulins There are gamma globulins from human blood - against measles, polio, infectious hepatitis, etc. This safe drugs, because they do not contain pathogens. Immune serums contain ready-made antibodies and are effective from the first minutes after administration.

NATIONAL PREVENTIVE VACCINATION CALENDAR AgeName of vaccination 12 hours First vaccination hepatitis B 3-7 days Tuberculosis vaccination 1 month Second vaccination hepatitis B 3 months First vaccination diphtheria, whooping cough, tetanus, polio 4.5 months Second vaccination diphtheria, whooping cough, tetanus, polio 6 months Third vaccination diphtheria, whooping cough , tetanus, polio Third vaccination hepatitis B 12 months Vaccination measles, rubella, mumps

Critical periods in the formation of the immune system of children The first critical period is the neonatal period (up to 28 days of life) The second critical period is 3-6 months of life, due to the destruction of maternal antibodies in the child’s body The third critical period is 2-3 years of the child’s life The fourth critical period is 6-7 years Fifth critical period – adolescence(12-13 years old for girls; years old for boys)

Factors that reduce protective functions body Main factors: alcoholism and alcoholism drug addiction and addiction psycho-emotional stress physical inactivity sleep deficiency excess weight A person’s susceptibility to infection depends on: individual characteristics human features of constitution, metabolic state, nutritional status, vitamin supply, climatic factors and season of the year, pollution environment living conditions and human activities lifestyle

Increasing the child’s body’s defenses using general strengthening techniques: hardening, contrast air baths, dressing the baby appropriately for the weather, taking multivitamins, trying to limit contact with other children as much as possible during periods of seasonal outbreaks viral diseases(for example, during a flu epidemic, you should not take your child to Christmas trees and other public events) traditional medicine, for example, garlic and onions When should you contact an immunologist? With frequent colds occurring with complications (ARVI, turning into bronchitis - inflammation of the bronchi, pneumonia - inflammation of the lungs or occurring against the background of ARVI purulent otitis– inflammation of the middle ear, etc.) In case of repeated infections, to which lifelong immunity must be developed ( chicken pox, rubella, measles, etc.). However, in such cases, it is necessary to take into account that if the baby has had these diseases before the age of 1 year, then immunity to them may not be stable and may not provide lifelong protection.