Introduction

Immunity is understood as a set of biological phenomena aimed at preserving the internal environment and protecting the body from infectious and other genetically foreign agents. There are the following types of infectious immunity:

antibacterial

antitoxic

antiviral

antifungal

antiprotozoal

Infectious immunity can be sterile (there is no pathogen in the body) and non-sterile (the pathogen is in the body). Innate immunity is present from birth; it can be specific or individual. Species immunity is the immunity of one species of animal or person to microorganisms that cause disease in other species. It is genetically determined in humans as a biological species. Species immunity is always active. Individual immunity is passive (placental immunity). Nonspecific protective factors are as follows: skin and mucous membranes, lymph nodes, lysozyme and other enzymes of the oral cavity and gastrointestinal tract, normal microflora, inflammation, phagocytic cells, natural killer cells, complement system, interferons. Phagocytosis.

I. The concept of the immune system

The immune system is a collection of all lymphoid organs and clusters of lymphoid cells in the body. Lymphoid organs are divided into central ones - thymus, bone marrow, bursa of Fabricius (in birds) and its analogue in animals - Peyer's patches; peripheral - spleen, lymph nodes, solitary follicles, blood and others. Its main component is lymphocytes. There are two main classes of lymphocytes: B lymphocytes and T lymphocytes. T cells are involved in cellular immunity, regulation of B cell activity, and delayed-type hypersensitivity. The following subpopulations of T-lymphocytes are distinguished: T-helpers (programmed to induce the proliferation and differentiation of other types of cells), suppressor T-cells, T-killers (secreting cytotoxic dimphokines). The main function of B lymphocytes is that, in response to an antigen, they are able to multiply and differentiate into plasma cells that produce antibodies. B - lymphocytes are divided into two subpopulations: 15 B1 and B2. B cells are long-lived B lymphocytes, derived from mature B cells as a result of stimulation by antigen with the participation of T lymphocytes.

The immune response is a chain of sequential complex cooperative processes occurring in the immune system in response to the action of an antigen in the body. There are primary and secondary immune responses, each of which consists of two phases: inductive and productive. Further, the immune response is possible in the form of one of three options: cellular, humoral and immunological tolerance. Antigens by origin: natural, artificial and synthetic; by chemical nature: proteins, carbohydrates (dextran), nucleic acids, conjugated antigens, polypeptides, lipids; by genetic relationship: autoantigen, isoantigens, alloantigen, xenoantigens. Antibodies are proteins synthesized under the influence of an antigen.

II. Immune system cells

Immunocompetent cells are cells that are part of the immune system. All of these cells originate from a single ancestral red bone marrow stem cell. All cells are divided into 2 types: granulocytes (granular) and agranulocytes (non-granular).

Granulocytes include:

neutrophils

eosinophils

basophils

To agranulocytes:

macrophages

lymphocytes (B, T)

Neutrophil granulocytes or neutrophils, segmented neutrophils, neutrophil leukocytes- a subtype of granulocytic leukocytes, called neutrophils because when stained according to Romanovsky, they are intensely stained with both the acidic dye eosin and basic dyes, in contrast to eosinophils, stained only with eosin, and from basophils, stained only with basic dyes.

Mature neutrophils have a segmented nucleus, that is, they belong to polymorphonuclear leukocytes, or polymorphonuclear cells. They are classical phagocytes: they have adhesiveness, motility, the ability to chemostaxis, as well as the ability to capture particles (for example, bacteria).

Mature segmented neutrophils are normally the main type of leukocytes circulating in human blood, accounting for 47% to 72% of the total number of leukocytes in the blood. Another 1-5% are normally young, functionally immature neutrophils that have a rod-shaped solid nucleus and do not have the nuclear segmentation characteristic of mature neutrophils - the so-called band neutrophils.

Neutrophils are capable of active amoeboid movement, extravasation (emigration outside the blood vessels), and chemotaxis (predominant movement towards sites of inflammation or tissue damage).

Neutrophils are capable of phagocytosis, and they are microphages, that is, they are able to absorb only relatively small foreign particles or cells. After phagocytosis of foreign particles, neutrophils usually die, releasing a large amount of biologically active substances that damage bacteria and fungi, increasing inflammation and chemotaxis of immune cells into the lesion. Neutrophils contain large amounts of myeloperoxidase, an enzyme that is capable of oxidizing chlorine anion to hypochlorite, a strong antibacterial agent. Myeloperoxidase, as a heme-containing protein, has a greenish color, which determines the greenish tint of the neutrophils themselves, the color of pus and some other secretions rich in neutrophils. Dead neutrophils, together with cellular detritus from tissues destroyed by inflammation and pyogenic microorganisms that caused inflammation, form a mass known as pus.

An increase in the proportion of neutrophils in the blood is called relative neutrophilosis, or relative neutrophilic leukocytosis. An increase in the absolute number of neutrophils in the blood is called absolute neutrophilosis. A decrease in the proportion of neutrophils in the blood is called relative neutropenia. A decrease in the absolute number of neutrophils in the blood is designated as absolute neutropenia.

Neutrophils play a very important role in protecting the body from bacterial and fungal infections, and a relatively lesser role in protecting against viral infections. Neutrophils play virtually no role in antitumor or anthelmintic defense.

The neutrophil response (infiltration of the inflammatory focus by neutrophils, an increase in the number of neutrophils in the blood, a shift in the leukocyte formula to the left with an increase in the proportion of “young” forms, indicating increased production of neutrophils by the bone marrow) is the very first response to bacterial and many other infections. The neutrophilic response in acute inflammation and infections always precedes the more specific lymphocytic response. In chronic inflammation and infections, the role of neutrophils is insignificant and the lymphocytic response predominates (infiltration of the inflammation site with lymphocytes, absolute or relative lymphocytosis in the blood).

Eosinophilic granulocytes or eosinophils, segmented eosinophils, eosinophilic leukocytes- a subtype of granulocytic blood leukocytes.

Eosinophils are so named because, when stained according to Romanovsky, they are intensely stained with the acidic dye eosin and are not stained with basic dyes, unlike basophils (stained only with basic dyes) and neutrophils (absorb both types of dyes). Also, a distinctive feature of an eosinophil is a bilobed nucleus (in a neutrophil it has 4-5 lobes, but in a basophil it is not segmented).

Eosinophils are capable of active amoeboid movement, extravasation (penetration beyond the walls of blood vessels) and chemotaxis (predominant movement towards the site of inflammation or tissue damage).

Eosinophils are also capable of absorbing and binding histamine and a number of other mediators of allergy and inflammation. They also have the ability to release these substances when needed, similar to basophils. That is, eosinophils are capable of playing both pro-allergic and protective anti-allergic roles. The percentage of eosinophils in the blood increases in allergic conditions.

Eosinophils are less numerous than neutrophils. Most eosinophils do not remain in the blood for long and, once they enter the tissues, remain there for a long time.

The normal level for humans is 120-350 eosinophils per microliter.

Basophilic granulocytes or basophils, segmented basophils, basophilic leukocytes- a subtype of granulocytic leukocytes. They contain a basophilic S-shaped nucleus, often invisible due to the overlap of the cytoplasm with histamine granules and other allergic mediators. Basophils are so named because, when stained according to Romanovsky, they intensively absorb the main dye and are not stained with acidic eosin, unlike eosinophils, which are stained only with eosin, and neutrophils, which absorb both dyes.

Basophils are very large granulocytes: they are larger than both neutrophils and eosinophils. Basophil granules contain large amounts of histamine, serotonin, leukotrienes, prostaglandins and other mediators of allergy and inflammation.

Basophils take an active part in the development of immediate allergic reactions (anaphylactic shock reactions). There is a misconception that basophils are the precursors of mast cells. Mast cells are very similar to basophils. Both cells are granulated and contain histamine and heparin. Both cells also release histamine when bound to immunoglobulin E. This similarity has led many to speculate that mast cells are the basophils in tissues. In addition, they have a common precursor in the bone marrow. However, basophils leave the bone marrow already mature, while mast cells circulate in an immature form, only eventually entering the tissue. Thanks to basophils, the poisons of insects or animals are immediately blocked in the tissues and do not spread throughout the body. Basophils also regulate blood clotting using heparin. However, the original statement is still true: basophils are direct relatives and analogues of tissue mast cells, or mast cells. Like tissue mast cells, basophils carry immunoglobulin E on their surface and are capable of degranulation (release of granule contents into the external environment) or autolysis (dissolution, cell lysis) upon contact with an allergen antigen. During degranulation or lysis of the basophil, a large amount of histamine, serotonin, leukotrienes, prostaglandins and other biologically active substances are released. This is what causes the observed manifestations of allergies and inflammation when exposed to allergens.

Basophils are capable of extravasation (emigration outside the blood vessels), and they can live outside the bloodstream, becoming resident tissue mast cells (mast cells).

Basophils have the ability to chemotaxis and phagocytosis. In addition, apparently, phagocytosis is neither the main nor natural (carried out under natural physiological conditions) activity for basophils. Their only function is instant degranulation, leading to increased blood flow and increased vascular permeability. increased influx of fluid and other granulocytes. In other words, the main function of basophils is to mobilize the remaining granulocytes to the site of inflammation.

Monocyte - a large mature mononuclear leukocyte of the agranulocyte group with a diameter of 18-20 microns with an eccentrically located polymorphic nucleus with a loose chromatin network and azurophilic granularity in the cytoplasm. Like lymphocytes, monocytes have a non-segmented nucleus. Monocyte is the most active phagocyte in peripheral blood. The cell is oval in shape with a large bean-shaped, chromatin-rich nucleus (which allows them to be distinguished from lymphocytes, which have a round, dark nucleus) and a large amount of cytoplasm, in which there are many lysosomes.

In addition to the blood, these cells are always present in large numbers in the lymph nodes, walls of the alveoli and sinuses of the liver, spleen and bone marrow.

Monocytes remain in the blood for 2-3 days, then they are released into the surrounding tissues, where, having reached maturity, they turn into tissue macrophages - histiocytes. Monocytes are also the precursors of Langerhans cells, microglia cells, and other cells capable of antigen processing and presentation.

Monocytes have a pronounced phagocytic function. These are the largest cells in the peripheral blood, they are macrophages, that is, they can absorb relatively large particles and cells or a large number of small particles and, as a rule, do not die after phagocytosis (death of monocytes is possible if the phagocytosed material has any cytotoxic properties for the monocyte). In this they differ from microphages - neutrophils and eosinophils, which are capable of absorbing only relatively small particles and, as a rule, die after phagocytosis.

Monocytes are able to phagocytose microbes in an acidic environment when neutrophils are inactive. By phagocytosis of microbes, dead leukocytes, damaged tissue cells, monocytes cleanse the site of inflammation and prepare it for regeneration. These cells form a delimiting shaft around indestructible foreign bodies.

Activated monocytes and tissue macrophages:

participate in the regulation of hematopoiesis (blood formation)

take part in the formation of the body’s specific immune response.

Monocytes, leaving the bloodstream, become macrophages, which, along with neutrophils, are the main “professional phagocytes.” Macrophages, however, are much larger and longer-lived than neutrophils. Macrophage precursor cells - monocytes, leaving the bone marrow, circulate in the blood for several days, and then migrate into tissues and grow there. At this time, the content of lysosomes and mitochondria increases in them. Near the inflammatory focus, they can multiply by division.

Monocytes are capable of emigrating into tissues and transforming into resident tissue macrophages. Monocytes are also capable, like other macrophages, of processing antigens and presenting antigens to T lymphocytes for recognition and learning, that is, they are the antigen-presenting cells of the immune system.

Macrophages are large cells that actively destroy bacteria. Macrophages accumulate in large quantities in areas of inflammation. Compared to neutrophils, monocytes are more active against viruses than bacteria, and are not destroyed during a reaction with a foreign antigen, therefore, pus does not form in areas of inflammation caused by viruses. Monocytes also accumulate in areas of chronic inflammation.

Monocytes secrete soluble cytokines that affect the functioning of other parts of the immune system. Cytokines secreted by monocytes are called monokines.

Monocytes synthesize individual components of the complement system. They recognize antigen and convert it into an immunogenic form (antigen presentation).

Monocytes produce both factors that enhance blood coagulation (thromboxanes, thromboplastins) and factors that stimulate fibrinolysis (plasminogen activators). Unlike B and T lymphocytes, macrophages and monocytes are not capable of specific antigen recognition.

T lymphocytes, or T cells- lymphocytes that develop in mammals in the thymus from precursors - prethymocytes, entering it from the red bone marrow. In the thymus, T lymphocytes differentiate to acquire T cell receptors (TCRs) and various co-receptors (surface markers). Play an important role in the acquired immune response. They provide recognition and destruction of cells carrying foreign antigens, enhance the effect of monocytes, NK cells, and also take part in switching immunoglobulin isotypes (at the beginning of the immune response, B cells synthesize IgM, later switch to the production of IgG, IgE, IgA).

Types of T lymphocytes:

T-cell receptors are the main surface protein complexes of T-lymphocytes responsible for recognizing processed antigens bound to molecules of the major histocompatibility complex on the surface of antigen-presenting cells. The T cell receptor is associated with another polypeptide membrane complex, CD3. The functions of the CD3 complex include transmitting signals into the cell, as well as stabilizing the T-cell receptor on the surface of the membrane. The T-cell receptor can associate with other surface proteins, TCR coreceptors. Depending on the coreceptor and the functions performed, two main types of T cells are distinguished.

T helper cells

T helper cells are T lymphocytes whose main function is to enhance the adaptive immune response. They activate T-killers, B-lymphocytes, monocytes, NK cells through direct contact, as well as humorally, releasing cytokines. The main feature of T helper cells is the presence of the CD4 coreceptor molecule on the cell surface. Helper T cells recognize antigens when their T cell receptor interacts with an antigen bound to class II major histocompatibility complex molecules.

Killer T cells

Helper T cells and killer T cells form a group of effector T lymphocytes directly responsible for the immune response. At the same time, there is another group of cells, regulatory T lymphocytes, whose function is to regulate the activity of effector T lymphocytes. By modulating the strength and duration of the immune response through regulation of the activity of T-effector cells, regulatory T cells maintain tolerance to the body's own antigens and prevent the development of autoimmune diseases. There are several mechanisms of suppression: direct, with direct contact between cells, and distant, carried out at a distance - for example, through soluble cytokines.

γδ T lymphocytes

γδ T lymphocytes are a small population of cells with a modified T cell receptor. Unlike most other T cells, whose receptor is formed by two α and β subunits, the T cell receptor γδ lymphocytes is formed by γ and δ subunits. These subunits do not interact with peptide antigens presented by MHC complexes. It is assumed that γδ T lymphocytes are involved in the recognition of lipid antigens.

B lymphocytes(B cells, from bursa fabricii birds, where they were first discovered) are a functional type of lymphocytes that play an important role in providing humoral immunity. When exposed to antigen or stimulated by T cells, some B lymphocytes transform into plasma cells capable of producing antibodies. Other activated B lymphocytes become memory B cells. In addition to producing antibodies, B cells perform many other functions: they act as antigen-presenting cells and produce cytokines and exosomes.

In human embryos and other mammals, B lymphocytes are formed in the liver and bone marrow from stem cells, and in adult mammals - only in the bone marrow. The differentiation of B lymphocytes takes place in several stages, each of which is characterized by the presence of certain protein markers and the degree of genetic rearrangement of immunoglobulin genes.

The following types of mature B lymphocytes are distinguished:

B cells themselves (also called “naive” B lymphocytes) are unactivated B lymphocytes that have not been in contact with the antigen. They do not contain Gall bodies and monoribosomes are scattered throughout the cytoplasm. They are polyspecific and have weak affinity for many antigens.

Memory B cells are activated B lymphocytes that have again entered the stage of small lymphocytes as a result of cooperation with T cells. They are a long-lived clone of B cells, provide a rapid immune response and produce a large amount of immunoglobulins upon repeated administration of the same antigen. They are called memory cells because they allow the immune system to “remember” the antigen for many years after its action has ceased. Memory B cells provide long-term immunity.

Plasma cells are the last stage of differentiation of antigen-activated B cells. Unlike other B cells, they carry few membrane antibodies and are capable of secreting soluble antibodies. They are large cells with an eccentrically located nucleus and a developed synthetic apparatus - the rough endoplasmic reticulum occupies almost the entire cytoplasm, and the Golgi apparatus is also developed. They are short-lived cells (2-3 days) and are quickly eliminated in the absence of the antigen that caused the immune response.

A characteristic feature of B cells is the presence of surface membrane-bound antibodies belonging to the IgM and IgD classes. In combination with other surface molecules, immunoglobulins form an antigen recognition receptive complex, responsible for antigen recognition. Also on the surface of B lymphocytes are MHC class II antigens, which are important for interaction with T cells, and some clones of B lymphocytes contain the CD5 marker, which is common to T cells. Complement component receptors C3b (Cr1, CD35) and C3d (Cr2, CD21) play a role in the activation of B cells. It should be noted that the markers CD19, CD20 and CD22 are used to identify B lymphocytes. Fc receptors are also found on the surface of B lymphocytes.

Natural killers- large granular lymphocytes that have cytotoxicity against tumor cells and cells infected with viruses. Currently, NK cells are considered a separate class of lymphocytes. NKs perform cytotoxic and cytokine-producing functions. NKs are one of the most important components of cellular innate immunity. NK are formed as a result of differentiation of lymphoblasts (the common precursors of all lymphocytes). They do not have T-cell receptors, CD3, or surface immunoglobulins, but usually carry CD16 and CD56 markers on their surface in humans or NK1.1/NK1.2 in some strains of mice. About 80% of NKs carry CD8.

These cells were called natural killer cells because, according to early ideas, they did not require activation to kill cells that do not carry MHC type I markers.

The main function of NK is the destruction of body cells that do not carry MHC1 on their surface and are thus inaccessible to the action of the main component of antiviral immunity - T-killers. A decrease in the amount of MHC1 on the cell surface may be a consequence of cell transformation into cancer or the action of viruses such as papillomavirus and HIV.

Macrophages, neutrophils, eosinophils, basophils and natural killer cells mediate the innate immune response, which is nonspecific.

The body is constantly under vigilant protection, which protects it from foreign particles. The defense system is immunity. It can be a collection of organs and tissues whose cells neutralize and remove harmful agents. Thanks to this defense system, people can fight diseases. Where is the human immune system located?

There is no clear answer to this question. Immunity is an abstract concept; it is not concentrated in one place, but is scattered throughout the body. Its failure leads to many adverse consequences. A person becomes vulnerable to foreign agents. He cannot fight infections and maintain his health. A number of pathological conditions arise. Depending on the mechanism of operation, immunity can be:

• Cellular;
• Humoral.

Each of them carries out its protective function through special cells. The first type is through T cells or T lymphocytes, which are divided into killer T cells, helper T cells, macrophages and neutrophils. Humoral is carried out thanks to B-lymphocytes and the antibodies they produce.

Another classification of immunity divides it into:

• Nonspecific, otherwise congenital;
• Specific, which is produced throughout life.

And also the protective system can be:

• Natural, developed after an illness;
• Artificial or passive, resulting from medical interventions - vaccination.

Where is

Immunity is a broad concept that combines many systems and tissues involved in the production of special substances. All protection bodies are divided into two large groups:

• Central – thymus and bone marrow, which are responsible for the production of lymph cells;
• Peripheral - spleen, lymph nodes, tonsils and groups of lymphoid formations. Their task is differentiation.

It is impossible to say where immunity is located in the human body. This is a general concept that reflects the work of many tissues and systems. The thymus, or otherwise the thymus gland, is the site of the formation of cellular immunity, that is, T cells. This organ is located behind the sternum and has age-related characteristics. In children and young people it is actively developed, and involution occurs over the years. This is reflected in a decrease in protective activity among older people.

Another central organ of the immune system is the bone marrow. It is represented by soft spongy tissue, which is located in tubular and flat bones. Its task is the formation of blood cells - leukocytes and erythrocytes, as well as platelets. The bone marrow produces B lymphocytes, which are the weapon of the humoral response.

One of the organs of peripheral immunity is the spleen. Its role is reduced to lymph production, disposal of old and defective red blood cells, as well as storage of blood cells. The spleen is often called a blood depot and a cemetery of red blood cells. It is located in the abdominal area under the left hypochondrium.

Lymph nodes are called biological filters. These are small spherical formations, normally up to 1 cm in size. Lymph nodes follow the course of the arteries. There are submandibular, postauricular, supra- and subclavian, axillary, popliteal, inguinal nodes. They are connected by ducts and together form the lymphatic system. Inflammatory processes are often accompanied by an increase in these nodes. They can reach the size of a chicken egg.

• lymphoid tissue that is located on both sides of the pharynx - these are the tonsils. Another similar island is localized in the intestinal walls and is called Peyer's patches. The exact place of their concentration is the appendix, which is also considered an immune organ. The ducts connecting the lymphoid formations contain lymph, a colorless liquid that includes a large number of defense cells.

Where is immunity located? It permeates the entire human body. Even where there are no protective tissues, there are lymph nodes and ducts. Defense never leaves its post. A person is under the control of a security system 24 hours a day.

How is it produced?

The role of all immune organs comes down to one thing – protective cells. Some form them, others differentiate, and others accumulate, while others act as a reservoir. The most important immune cell products include:

Thanks to the immune organs, the production of these cells is possible. They are direct participants in the battlefield. “Soldiers” of the defense system who fight against strangers who have broken into the body.

Functions

The main task of immunity is defense against unwanted substances. Among the main ones are:

• Preventing the introduction of foreign agents through the presence of biological barriers;
• Destruction of defective and old cells of the body whose life cycle has come to an end;
• Neutralization of a harmful microbe when it enters;
• Elimination, that is, removal of antigens.

What does human immunity depend on?

Defense mechanisms are formed under the influence of many factors that determine the strength of the response against antigens. An important role is played by:

• Heredity is the genetic predisposition of a person, which he inherited from his parents. Immunity will directly depend on this factor;
• The environment can also influence defense mechanisms to a large extent. Two twins who have similar genetic material but live in different environments will have different immune status;
• The quality and quantity of food consumed, and, more precisely, its vitamin and mineral composition;
• Lifestyle – his daily routine, work and rest schedule, the presence of bad habits;
• Physical activity or lack thereof. Physical inactivity leads to the fact that the patient will be in a state of reduced muscle tone, gas exchange and, as a result, susceptible to immune disorders;
• Acquired and congenital diseases.

These factors will be the answer to the question “what does human immunity depend on?”

Causes of weakened human immunity

The following diseases and conditions can trigger the process of reducing the body’s protective arsenal:

The causes of the external environment are:

• Incorrect lifestyle, with increased psycho-emotional or physical stress, unbalanced diet and sleep disturbances;
• Negative environmental conditions;
• Addiction to alcohol, smoking;
• Lack of vitamins and minerals.

The state of decreased protective function of the body requires mandatory correction. You need to increase your immunity under the supervision of a doctor. After studying the patient's medical history, conducting an examination and using diagnostic methods, the doctor can prescribe the necessary treatment without requiring the person to take medication. Raising your immune status is not an easy task, but it is doable. You can’t boost your immunity on your own without a doctor’s advice. The main thing is to strengthen your body wisely and prepare for it. Then climbing the ladder of health will be much more pleasant and interesting.

The immune system is a collection of special tissues, organs and cells. This is a rather complex structure. Next, we will figure out what elements are included in its composition, as well as what are the functions of the immune system.

General information

The main functions of the immune system are the destruction of foreign compounds that enter the body and protection against various pathologies. The structure represents a barrier to infections of a fungal, viral, or bacterial nature. When the body is weak or malfunctions, the likelihood of foreign agents entering the body increases. As a result, various diseases may arise.

Historical background

The concept of “immunity” was introduced into science by the Russian scientist Mechnikov and the German figure Ehrlich. They examined existing ones that are activated in the process of the body’s fight against various pathologies. First of all, scientists were interested in the reaction to infections. In 1908, their work in the field of studying the immune response was awarded the Nobel Prize. In addition, the works of the Frenchman Louis Pasteur made a significant contribution to research. He developed a vaccination method against a number of infections that posed a danger to humans. Initially, there was an opinion that the body’s protective structures directed their activity only to eliminate infections. However, subsequent studies by the Englishman Medawar proved that immune mechanisms are triggered by the invasion of any foreign agent, and in general react to any harmful interference. Today, the protective structure is mainly understood as the body’s resistance to various types of antigens. In addition, immunity is a response of the body aimed not only at destruction, but also at eliminating “enemies”. If the body did not have protective forces, then people would not be able to exist normally in environmental conditions. Having immunity allows you to cope with pathologies and live to old age.

Immune system organs

They are divided into two large groups. The central immune system is involved in the formation of protective elements. In humans, this part of the structure includes the thymus and bone marrow. The peripheral organs of the immune system provide an environment where mature protective elements neutralize antigens. This part of the structure includes the lymph nodes, spleen, and lymphoid tissue in the digestive tract. It has also been established that the skin and neuroglia of the central nervous system have protective properties. In addition to those listed above, there are also intra-barrier and extra-barrier tissues and organs of the immune system. The first category includes skin. Transbarrier tissues and organs of the immune system: central nervous system, eyes, testes, fetus (during pregnancy), thymic parenchyma.

Objectives of the structure

Immunocompetent cells in lymphoid structures are represented predominantly by lymphocytes. They are recycled between the constituent components of the protection. It is believed that they do not return to the bone marrow and thymus. The functions of the immune system of organs are as follows:

Lymph node

This element is formed by soft tissues. The lymph node has an oval shape. Its size is 0.2-1.0 cm. It contains immunocompetent cells in large quantities. The formation has a special structure that allows it to form a large surface for the exchange of lymph and blood flowing through the capillaries. The latter comes from the arteriole and exits through the venule. Immunization of cells and formation of antibodies occurs in the lymph node. In addition, the formation filters foreign agents and small particles. The lymph nodes in each area of ​​the body contain their own set of antibodies.

Spleen

Outwardly, it resembles a large lymph node. The above are the main functions of the organs' immune system. The spleen also performs several other tasks. For example, in addition to producing lymphocytes, blood is filtered in it and its elements are stored. This is where the destruction of old and defective cells occurs. The mass of the spleen is about 140-200 grams. It is presented in the form of a network of reticular cells. They are located around sinusoids (blood capillaries). The spleen is mainly filled with red blood cells or white blood cells. These cells do not contact each other and change in composition and quantity. When the smooth muscle capsular cords contract, a certain number of moving elements are pushed out. As a result, the spleen decreases in volume. This entire process is stimulated by the influence of norepinephrine and adrenaline. These compounds are secreted by postganglionic sympathetic fibers or the adrenal medulla.

Bone marrow

This element is a soft spongy tissue. It is located inside flat and tubular bones. The central organs of the immune system produce the necessary elements, which are then distributed among the zones of the body. The bone marrow produces platelets, red blood cells and white blood cells. Like other blood cells, they mature after they acquire immune competence. In other words, receptors will be formed on their membranes, characterizing the similarity of the element with others similar to it. In addition, conditions are created for the acquisition of protective properties by such organs of the immune system as tonsils, Peyer's patches of the intestine, and thymus. In the latter, the maturation of B-lymphocytes occurs, which have a huge number (one hundred to two hundred times more than T-lymphocytes) of microvilli. Blood flow is carried out through vessels that include sinusoids. Through them, not only other compounds penetrate into the bone marrow. Sinusoids are channels for the movement of blood cells. Under stress, the current decreases almost by half. When you calm down, blood circulation increases up to eight times the volume.

Peyer's patches

These elements are concentrated in the intestinal wall. They are presented in the form of clusters of lymphoid tissue. The main role belongs to the circulation system. It consists of lymphatic ducts connecting the nodes. Liquid is transported through these channels. It has no color. A large number of lymphocytes are present in the fluid. These elements provide protection to the body from diseases.

Thymus

It is also called the thymus gland. The reproduction and maturation of lymphoid elements occurs in the thymus. The thymus gland performs endocrine functions. Thymosin is released from its epithelium into the blood. In addition, the thymus is an immune-producing organ. It is where T-lymphocytes are formed. This process occurs due to the division of elements that have receptors for foreign antigens that entered the body in childhood. The formation of T-lymphocytes occurs regardless of their number in the blood. Does not affect the process and the content of antigens. In young people and children, the thymus is more active than in older people. Over the years, the thymus gland decreases in size, and its work becomes less fast. Suppression of T-lymphocytes occurs under stress. We can talk about, for example, cold, heat, psycho-emotional stress, blood loss, fasting, excessive physical activity. People exposed to stressful situations have weak immunity.

Other items

The vermiform appendix is ​​also an organ of the immune system. It is also called the "intestinal tonsil". Under the influence of changes in the activity of the initial part of the colon, the volume of lymph tissue also changes. The organs of the immune system, diagrammed below, also include the tonsils. They are located on both sides of the pharynx. Tonsils are represented by small accumulations of lymphoid tissue.

The main defenders of the body

The secondary and central organs of the immune system are described above. The diagram presented in the article shows that its structures are distributed throughout the body. The main defenders are lymphocytes. It is these cells that are responsible for the destruction of diseased elements (tumor, infected, pathologically dangerous) or foreign microorganisms. The most important are T and B lymphocytes. Their work is carried out in conjunction with other immune cells. They all prevent foreign substances from invading the body. At the initial stage, T-lymphocytes are in some way “trained” to distinguish normal (self) proteins from foreign ones. This process occurs in the thymus during childhood, since it is during this period that the thymus gland is most active.

The work of the body's defenses

It should be said that the immune system was formed during a long evolutionary process. In modern people, this structure acts like a well-oiled mechanism. It helps a person cope with the negative influence of environmental conditions. The tasks of the structure include not only recognition, but also the removal of foreign agents that have entered the body, as well as decay products and pathologically changed elements. The immune system has the ability to detect a large number of foreign substances and microorganisms. The main purpose of the structure is to preserve the integrity of the internal environment and its biological individuality.

Recognition process

How does the immune system identify "enemies"? This process occurs at the genetic level. Here it should be said that each cell has its own genetic information, characteristic only for a given person. It is analyzed by the protective structure in the process of detecting penetration into the body or changes in it. If the genetic information of the captured agent matches its own, then it is not an enemy. If not, then, accordingly, it is a foreign agent. In immunology, “enemies” are usually called antigens. After detecting malicious elements, the protective structure turns on its mechanisms, and the “fight” begins. For each specific antigen, the immune system produces specific cells - antibodies. They bind to antigens and neutralize them.

Allergic reaction

It is one of the defense mechanisms. This condition is characterized by an increased response to allergens. These “enemies” include objects or compounds that negatively affect the body. Allergens are external and internal. The first include, for example, food products, medicines, various chemicals (deodorants, perfumes, etc.). Internal allergens are tissues of the body itself, usually with altered properties. For example, with burns, the defense system perceives dead structures as foreign. In this regard, she begins to produce antibodies against them. Reactions to bees, wasps and other insects can be considered similar. The development of an allergic reaction can occur sequentially or rapidly.

Child's immune system

Its formation begins in the very first weeks of gestation. A baby's immune system continues to develop after birth. The laying of the main protective elements is carried out in the thymus and bone marrow of the fetus. While the baby is in the mother's womb, his body encounters a small number of microorganisms. In this regard, its defense mechanisms are inactive. Before birth, the baby is protected from infections by the mother's immunoglobulins. If any factors adversely affect it, then the correct formation and development of the baby’s defenses may be disrupted. After birth, in this case, the child may get sick more often than other children. But things could happen differently. For example, during pregnancy, the mother of the child can suffer from an infectious disease. And the fetus can develop a strong immunity to this pathology.

After birth, the body is attacked by a huge number of microbes. The immune system must resist them. During the first years of life, the body's protective structures undergo a kind of “training” to recognize and destroy antigens. At the same time, contacts with microorganisms are remembered. As a result, “immunological memory” is formed. It is necessary for a faster manifestation of the reaction to already known antigens. It must be assumed that a newborn’s immunity is weak and he is not always able to cope with danger. In this case, antibodies received in utero from the mother come to the rescue. They are present in the body for approximately the first four months of life. Over the next two months, proteins received from the mother are gradually destroyed. Between four and six months, the baby is most susceptible to illness. Intensive formation of a child’s immune system occurs before the age of seven. During development, the body becomes acquainted with new antigens. During this entire period, the immune system is trained and prepared for adult life.

How to help a fragile body?

Experts recommend taking care of your child’s immune system even before birth. This means that the expectant mother needs to strengthen her protective structure. During the prenatal period, a woman needs to eat right, take special microelements and vitamins. Moderate physical activity is also important for immunity. In the first year of life, a child needs to receive breast milk. It is recommended to continue breastfeeding until at least 4-5 months. With milk, protective elements penetrate into the baby’s body. During this period they are very important for immunity. You can even put milk in your child’s nose during a flu epidemic. It contains a lot of useful compounds and will help the baby cope with negative factors.

Additional Methods

Training the immune system can be done in various ways. The most common are hardening, massage, gymnastics in a well-ventilated area, sun and air baths, and swimming. There are also various remedies for immunity. One of them is vaccinations. They have the ability to activate protective mechanisms and stimulate the production of immunoglobulins. Thanks to the introduction of special serums, a memory of the body’s structures to the injected material is formed. Another means for immunity are special drugs. They stimulate the activity of the body's protective structure. These medications are called immunostimulants. These are interferon preparations (Laferon, Reaferon), interferonogens (Poludan, Abrizol, Prodigiozan), leukopoiesis stimulators - Methyluracil, Pentoxyl, immunostimulants of microbial origin - Prodignozan, Pyrogenal. , “Bronchomunal”, immunostimulants of plant origin - Schisandra tincture, Eleutherococcus extract, vitamins and much more. etc.

Only an immunologist or pediatrician can prescribe these medications. Independent use of drugs in this group is highly discouraged.

Everyone has heard and knows that the immune system, immunity, is “so that a person gets sick less.”

But I am sure that most people who are not specialists in this field have little idea of ​​the importance of immunity and the normal functioning of the immune system, not only for human health, but also for his life as such.

What is immunity and the immune system?

Immunity, in the generally accepted understanding, is the body’s ability to resist foreign, usually pathogenic, microorganisms and substances when they enter the body and its integument - mucous membranes and skin.

Here we can safely include the body’s ability to some limited recovery, as a whole, and individual organs and systems.

In general, it turns out that immunity is the body’s ability to maintain itself in an optimal biological, and therefore mental, state.

And, immediately pay attention to this: immunity, its state, affects not only the biological indicators of the human body, but also its psyche.

For the psyche is one of the systems of the body, and even if we assume that the immune system does not act on the psyche directly, then it acts on it through the state of the body as a whole.

And, therefore, we must imagine and understand that the state of the immune system and the immune system that provides it affects:

1. Not only on the condition and functioning of the human body and all its systems;

2. But, influencing the nervous system, it also affects a person’s consciousness: his feelings, thoughts and, in general, his worldview, as a view of the world around him and himself.

In fact, we have known this for a long time: A healthy mind in a healthy body. And everyone has repeatedly observed how a person’s behavior, attitude and ideas change, depending on the state of his body.

So, it is precisely this condition that is determined by the immune system, creating immunity in a person of one quality or another.

I repeat, you need to understand this feature of immunity to influence not only the body, but also the human brain, as one of the very important ones.

What is the immune system?

I don’t think that a non-specialist in this field, that is, most people, does not need to know all its elements and connections. Moreover, as far as we know, all the secrets of the immune system and the mechanisms of its work are still unknown to scientists.

We need to understand that the immune system is a very complex mechanism for protecting and maintaining the human body and psyche in viable, optimal states.

And that the immune system works at the micro level of the human body: the scope of its actions, functions and elements is located not only on the cellular, but also on the intracellular contents.

Immune system: innate and acquired immunity

Being fundamental in the life of the body, the immune system cannot but be built into the body from the moment of its conception. That is, it is congenital - inherited, through the human genome.

Naturally, innate immunity can protect the body only from those foreign microorganisms and substances that are usually found in the human environment and in the person himself.

BUT, the living world around a person is alive in order to generate new microbes, viruses or their varieties, as products of development. Therefore, the immune system has a second level of defense: acquired immunity.

Acquired immunity, of course, is more complex in comparison with innate immunity, because it is a unique biofactory of the body, a function that:

1. Recognize a foreign microorganism or substance.

2. Produce anti substance or anti organisms – antibodies in sufficient quantities.

3. Destroy foreign microparticles.

4. Remove the remains of the neutralized substance and destroyed harmful bodies and dead antibodies.

5. Give a command, and possibly participate, in restoring the normal functioning of the affected organ, system or organism as a whole.

6. Remember the experience of repelling an attack from this organism or substance.

7. Go into standby mode: monitor for the appearance of foreign substances and organisms harmful to the body.

Please note:

Although the mechanism of operation of innate and acquired immunities does not seem so complicated;
- but taking into account its systematic nature, and even at the micro level;
- taking into account the inclusion and dependence of the immune system in all other systems and subsystems of the body;
- considering that the immune system, a priori, works fully only in extreme conditions of the body, -

It is easy to understand that disruptions in the immune system are not only possible, but also inevitable. This is what we observe in the case of diseases with fatal outcomes.

Unless, of course, the person receives effective drug treatment or effective surgery. Or, the person himself does not influence the immune system in such a way as to help it, to mobilize it to perform its task.

The immune system contains all known diseases.

About 30 years ago, in some publications, the following information slipped and disappeared: Scientists immunologists discovered that the human body contains almost all diseases known to people, including cancer.

Why did she slip and disappear?

In my opinion, because if this is so, then it is necessary to reconsider not only traditional ideas about the immune system and immunity as such, but also to rethink ideas about diseases and, most importantly, about their treatment. Why?

1. Look here: one of the main functions of the immune system is to recognize a foreign substance or microorganism.

It is clear that without this, it will not be able to produce the necessary antisubstances or antibodies. BUT, how does the immune system make this recognition?

2. To admit that she does this through mental operations is to admit that intelligence is possible at the cell level - the cell is the carrier of the mind.

This does not fit with our knowledge about possible carriers of intelligence - a cell, any cell, simply, has nothing to think with.

3. The simplest operation of recognizing any object by any living object capable of reflection is comparison.

4. What should be in the immune system to compare with emerging foreign substances or microorganisms?

5. Of course, one can imagine that the human immune system may contain information codes for all substances and all microorganisms.

Well, at least only those that a person has already encountered. You can imagine, but you can’t imagine anymore.

6. How and where can the human body sort and store not only so many complex chemical formulas of microorganisms hostile to it, but also information about their systems - elements and their structural connections? But nowhere and no way.

7. What can the immune system do to know and recognize “enemies by sight”?

8. The only option: to have them in yourself, is to store these substances themselves and these microorganisms themselves in their elements.

9. Have and store, BUT, in a strictly defined quantity and quality, so that they do not cause harm to the body.

10. This means that the immune system not only contains a repository of all harmful substances and microorganisms known to it that cause diseases.

But it also constantly regulates their quantity and quality so that they do not lead to these diseases, multiplying and intensifying to a critical level.

This means that immunologists were right when they found multiple traces of known human diseases in a human body that was conditionally healthy from these diseases.

And logically assuming that the immune system contains ALL substances and all organisms that can cause disease in humans.

Well, of course: what is vaccination if not the introduction of NEW pathogenic organisms into the body, in small quantities and in a weakened form?

Immune system, immunity. To be healthy is to get sick and get well

Based on the fact that the human body is a self-preserving and restoring system, which is obvious.

And, with difficulty understanding what this body does through the immune system and immunity, we must come to the following conclusions:

1. Treat a person: this is to strengthen or restore his immune system, so that she can destroy the pathogenic organisms inside a person that have gone out of obedience - multiplied and strengthened.

And not as we do now, in most cases: with medication or surgery we destroy these microbes and viruses themselves - protomicrobes, and the consequences of their reproduction.

After all, the saying: We treat one thing, and cripple another, should correctly sound like this: We treat one thing, but we cripple everything.

For, by destroying pathogenic microbes and the consequences of their activities with the help of “chemistry,” we destroy the immune system itself, at a minimum, disrupting its work.

And surgical removal of the consequences of the proliferation of microorganisms and substances is generally barbaric.

The savagery of both people who allowed tumors to grow in themselves, and the state of medicine, which finds nothing better than to fight the consequences of diseases than to eliminate their causes.

Or does someone need to treat people THIS way?

2. This means that you need to look at the immune system, not as an assistant in the fight against disease, but as the main instrument of the natural, natural mechanism of a person’s struggle for his survival and maintaining the body and psyche in an optimal – healthy state.

3. This means that a person cannot be absolutely healthy.– cannot but have pathogenic substances and organisms in itself.

And most importantly, any disease cannot CONSTANTLY occur in the body and the fight against it is recovery.

Because otherwise, if a person does not get sick, his immune system will stop and collapse from inaction.

That is: A completely healthy person is a dead person - this is not a joke, but the truth. This means that to be healthy is not to get sick, but to get well.

And to get sick is when the entry into the body from outside or the reproduction inside the body of foreign pathogenic substances and organisms has exceeded the resistance of the immune system.

4. In other words, a disease of the body - its removal from an optimal state - occurs in three cases:

1) When, from the outside, during infection, new or significantly modified microorganisms or substances enter the body, samples of which are not available in the immune system of this person.

That is, the immune system cannot understand what it should protect the body from, and with what - what antibody or antimatter.

Then, either death, or the destruction of these microbes, viruses, substances, through medication.

Or a mutation in the immune system that can then produce antibodies or anti-substances against these enemies when it randomly creates an antibody or neutralizing substance.

Remember the rare cases of people recovering from widespread and fatal epidemics, when some people became immune to this new infection.

How could it have appeared, except as a result of such random changes in the immune system, when it could find and produce an antibody in an attempt to cope with an unknown microorganism?

2) When a large amount of a substance or microorganisms enters the human body from the outside, and the body’s immune system cannot cope with this “invasion.”

This also includes a situation when the immune system is attacked simultaneously by various harmful substances and microorganisms.

Well, for example, the classic Russian version: a person gets sick, from the proliferation of microbes, viruses, or from poisoning with substances. His immune system begins to fight the sources of the disease.

And here, according to folk tradition and recipes, a significant or certain amount of “vodka is poured into the body, for warming and to kill germs.”

As a result, the immune system begins to fight not only microbes or toxic substances, but also vodka, as a common poison for the body.

3) When the immune system is weakened and ceases to cope not only with external enemies, but also with microbes present in the body.

These are situations when the disease is diagnosed as “it’s unclear where it came from” and “why me”, in the dark thoughts of the sick person. A classic example: the manifestation of herpes.

When and how do we weaken and destroy the immune system?

Every person needs to know that by weakening, and even more so, destroying the immune system, by reducing or destroying his immunity, he automatically becomes ill with one or another disease.

It gets sick to one degree or another, and with one or another consequence, even death.

The immune system is at risk when:

1. A person himself literally pushes foreign substances and microorganisms into his body.

No, of course, this should be done, and even very necessary, but only in such quantities that the immune system can not only process them, but also remember them, for further fight against them.

Let's say you need to kiss, and with a kiss you receive millions of new microbes and viruses, which the immune system will process, take note of and destroy the unnecessary ones.

But why kiss an infectious (read: unknown) person who has a huge number of germs and viruses that your immune system cannot handle?

Or, of course, you need to eat all sorts of different foods, but why consume it in incredible quantities?

Or, why consume an incredible amount of all kinds of liquids, and not only water, but also compounds that, in essence, are poisons?

Or why fill your stomach when the previous batch of food is still “in your throat” - before three hours? To cause rotting processes in the gastrointestinal tract, with the release of toxins and simply poisons?

You need to clearly understand that EVERYTHING that enters the body through the mouth, nose, skin - all substances and organic matter - is subject to analysis and reaction of the immune system.

Which, like everything in the body, has not only its own resource, but also its own operating parameters.

Of course, like everything in the body, the immune system has reserves, but they are not immense. As soon as the measure is violated, a failure occurs in the immune system. And this is, at a minimum, a slight malaise.

And the more such rapes the immune system receives over itself, the faster violations in it will lead to significant or fatal diseases of the body.

2. It is often said that the immune system, immunity, is weakened and disrupted during peak loads on the human body, on the body and on the psyche.

This is, of course, true, but you need to understand here that it is not the consequences of excessive loads, but their causes:

1) Great physical stress on the body leads to the formation of a large number of decay products, which, sometimes, the immune system does not have time to process, up to the command to the body: Stop!

That is, as a rule, if a person cannot bear physical stress on his body, the matter is not only in the weakness of the muscles and the lack of training of his systems. And, first of all: the weakness of the human immune system.

2) The nervous system is designed in such a way that the whole, completely and individually, works on the principle of excitation and depression, inhibition.

Hence, if a person’s nervous system is depressed, then, thereby, it gives a command to the entire body to slow down, or even to begin the process of self-destruction.

For example, if a person is in a state of “life is not nice,” the immune system is weakened and begins to malfunction.

And there is no mysticism here: we must not forget that the nervous system, even without the participation of human consciousness, itself, a priori, is the command center of the body.

But overexcitation of the nervous system will also have a negative impact on the body. Even, for example, positive emotions.

Its excessive activity and associated physical activity will begin to punch holes in the immune system, which simply will not keep up with them, due to the bulkiness and complexity of its system and the responsibility of its functions. That's why:

How to maintain the immune system and increase immunity?

1. Sleep until you get enough sleep, but don’t oversleep - don’t “roll around in bed.”

It is highly desirable for the immune system to have a midday nap and periodic rest during the day.

2. Balanced nutrition.

It is RATIONAL nutrition, not sensual nutrition. That is, modern man can no longer eat, guided by his feelings of hunger, appetite, pleasure or displeasure from eating this or that food.

Why? But because, firstly, these feelings, from the first days of a modern person’s life, have been “confused” - they do not correspond to the true needs of a person in receiving and eating food.

Because even when breastfeeding a child, the mother does it incorrectly - often or rarely, and already begins to feed him, through milk, with nutrients that are unnatural for humans, which she consumes herself.

And secondly, the mind was given to man so that he could regulate his life activity, including eating, and not be guided only by feelings, like an animal.

In other words, a person should eat not what he wants, when and how much he wants, but as much and then as his mind tells him.

Of course, if in this mind there is basic knowledge of people about reasonable food intake. Otherwise, the immune system and immunity will behave like systems uncontrollable by anyone or anything, that is, they will malfunction and self-destruct.

3. The body, a priori, must have physical activity - this is its essential property - “to move”.

But, in the case of extreme physical and mental stress, as mentioned above, the immune system and immunity will inevitably fail.

How to recognize problems in the immune system - problems with immunity?

1. Rapid and severe fatigue, even with little physical and mental stress on the body.

2. A feeling of constant fatigue - drowsiness, less often - insomnia - when overexcited, when the immune system cannot “come to its senses”.

3. Headache and other pains, in various parts of the body and skeleton, with unexpressed symptoms - a person cannot understand why and what hurts. Often, there is a feeling that “everything hurts.”

The onset of malfunctions and failures of the immune system manifest themselves as follows:

1. “Unreasonable” colds, as well as unsatisfactory functioning of the gastrointestinal tract.

2. Various allergies.

3. Unstable body temperature, with periodic increases to borderline conditions, and chills.

An increase in temperature is one of the mechanisms of the immune system in the event of extreme damage to the body by foreign microorganisms and substances.

And chills - when you feel chills - are attempts by the immune system to shake itself up and mobilize for the fight.

Main conclusion: Taking care of your health means preserving and strengthening your immune system and preserving your immunity. Shouldn't every person know and understand this?

The human body is a complex system, thought out by nature down to the smallest detail. When any mechanism fails, the integrity of the structure is disrupted and a disease develops. To prevent changes, it is necessary not only to lead a healthy lifestyle, but also to properly strengthen the performance of internal organs, which is responsible for immunity.

What does human immunity consist of?

Resistance is a protective system that helps maintain the constancy of processes in homeostatic mechanisms, the production of antibodies to pathogenic agents and the suppression of mutations of one’s own cells.

Homeostasis is the internal environment, liquid components: blood, lymph, salts, spinal, tissue, protein fractions, fat-like compounds and other substances that form the metabolic processes necessary for the normal course of physiological and chemical reactions that determine full healthy life. By maintaining the relative constancy of processes, a person is protected from pathogenic and dangerous microorganisms. A change in homeostatic parameters indicates the presence of a malfunction in the functioning of resistance and a disruption in the full performance of the entire organism.

The immune system consists of an innate, genetically determined resistance status, as well as acquired types of immunity to foreign agents.

The nonspecific type is responsible for 60% protection. Appearing in the prenatal state, after birth resistance in a child is capable of:

• Distinguish between cellular structure based on the principle of friend or foe;
• Activate phagocytosis;
• Compliment system: globulins that cause a sequence of specific immune responses;
• Cytokines;
• Glycoprotein bonds.

Thanks to well-functioning mechanisms and reactions in the body, in the presence of a threat, processes are activated to detect, absorb and destroy foreign agents.

A specific type of resistance is developed through direct contact with the antigen. Improves mechanisms throughout life. Carried out:

• Humoral reactions - the formation of protein antibodies and immunoglobulins. They are distinguished by structure and functionality: A, E, M, G, D;
• Cellular - involves active participation in the destruction of a pathogenic object by bodies of the T-type lymphocytic system - thymus-dependent, these include suppressors, killers, helpers, and cytotoxic ones.

All structures, both specific and non-specific, work together and provide strong protection, forming an increase in the immune response from local, that is, local resistance, to the activation of all resistance mechanisms as the infection spreads.

Classified into:

• Congenital - an individual genetic feature that prevents or causes a disease of a certain type. For example, a person is not susceptible to severe pathologies that affect animal organisms;
• Acquired - a manifestation of the function of remembering a foreign object and enhancing the action of defense mechanisms against re-invasion of infection, since immunity has been developed in the form of an antibody.

Also considered in types of resistance:

• Natural, produced upon direct contact with the antigen;
• Artificial - obtained by introducing vaccines, serums, immunoglobulins.

The body's resistance, just like any other system, is susceptible to diseases classified by the presence and activity of reactions:

• Allergy;
• Inadequate effect on native cells;
• Deficit in immunity abilities.

To ensure reliable protection, methods of prevention and strengthening resistance are used:

• Vaccination;
• Taking vitamins and minerals;
• Proper nutrition;
• Healthy active lifestyle.

Where is

What is included in the human immune system - each part carries a certain functionality and is divided into:

• Central;
• Peripheral.

Which organ is responsible for human immunity - a full-fledged resistant complex connects all tissues and central anatomical structures between its parts.

The location of the main elements of immunity is clearly shown by diagrams of the human structure:

• Adenoids, tonsils;
• Jugular vein;
• Thymus gland;
• Lymph nodes and ducts: cervical, axillary, inguinal, intestinal, afferent;
• Spleen;
• Red bone marrow.

Also in the human body there is a widespread network of lymph nodes, providing control over every part of the body.

Competent cells of the resistance system constantly circulate in the blood and other fluids, providing instant recognition, dissemination of information about the detection of an intruder and the selection of attack mechanisms to destroy the pathogen.

How is it produced?

In the human body, which organ is responsible for immunity is of great importance, since the mechanism of the onset and course of the immune response consists of cumulative sequential reactions and functions of nonspecific resistance, humoral and cellular defense.

The primary line of defense is aimed at preventing infection from entering internal structures. These include: healthy skin, mucous membranes, natural secretory fluids, blood-brain barriers. As well as special protein compounds - interferon.

The second direction of protective elements activates activity when an infection has directly entered the body. There are systems:

• Antigen recognition - monocytes;
• Execution and destruction - lymphocytes of type T, B;
• Immunoglobulins.

Also, a delayed or rapid allergic reaction to an irritant is considered part of a resistant response.

In the human body, protective immunocompetent cells are formed:

• In the first case, in the spleen: phagocytes, soluble bodies: cytokines, complement system, interleukins, glycoprotein;
• In the second, the elements undergo the process of formation from stem cells entering the thymus. When ripe, they spread throughout the body and accumulate in lymphoid tissue and nodes.

Mechanism of immune response:

• Upon penetration, a chemokine is formed, which causes inflammation and attracts resistant bodies;
• Increased activity of phagocytes and macrophages;
• Formation of immunoglobulins;
• Selection of reaction to ensure antibody-antigen communication.

Functions

The main features of the internal structures included in the resistance system are best considered in table form

immune organs	characteristic
Red bone marrow	A semi-liquid substance of spongy consistency with a dark burgundy tint. It is located depending on age: child - all bones, teenagers and older generation - cranial bones, pelvis, ribs, sternum, spine.	Provides hematopoiesis: leukocytes, platelets. erythrocytes, full resistance: lymphocytes (Supports the maturation process of type B, communication with type T cells), macrophages, stem elements.
Thymus gland	Appears in the prenatal period. It decreases with age. Located in the upper part of the sternum in the form of lobes covering the trachea.	Formation of immune hormones, development of protective antibodies. Participates in metabolic processes, including regulating the mineralization of the bone structure. Provides neuromuscular connection.
Spleen	Oval organ in the form of a gland. Located at the top of the peritoneum behind the stomach.	Stores a supply of blood, protects against the destruction of corpuscles. Contains a supply of mature lymphocytes. Forms the ability to produce antibodies and immunoglobulins. Activates humoral reactions. The main functions are considered to be: recognition of pathogenic objects, as well as processing and disposal of old and defective heme bodies.
Types of lymphoid tissue:
Tonsils	Located in the pharynx.	Provides local border immunity of the upper respiratory tract. Supports the microflora of the mucous membranes in the mouth.
Peyer's patches	Distributed in the intestines.	Form a resistant response. Prevents the growth of opportunistic and pathogenic fauna. The process of lymphocyte maturation is normalized and responded to.
	They are found in the armpits, groin, and other places along the path of lymph flow. There are about 500 of them in the body. They have a wide variety of shapes... it is a capsule covered with connective tissue with an internal system of sinuses. On the one hand there is an entrance for arteries and nerves, on the other there are vessels and venous channels.	Helps delay pathogens that have entered the lymph. Actively participates in the formation of immune and plasma cells.
Immunocompetent cells	Lymphocyte type: B - antibody producers; T - stem cells of the red bone marrow, maturing in the thymus,	They provide a resistant response, determine the strength of reactive processes, and form humoral mechanisms. Capable of remembering antigen.