Shaped element responsible for immunity. Properties of the human immune system

The environment around us - air, water, soil, objects contain a lot of microorganisms that can harm human health. But due to the fact that the immune system stands guard over our well-being, in most cases this still does not happen. The immune system every minute "fights" with the army of bacteria and viruses, safely "beating off" all these malicious "attacks".

The human immune system is very complex. It includes several organs interconnected by a continuous network of lymphatic ducts.

Structure immune system human

The organs of the immune system include:

Bone marrow;
thymus (thymus gland);
spleen;
lymph nodes and islets of lymphatic tissue.

Bone marrow

The bone marrow is located in the spongy substance of the bone tissue. The total weight of this organ is 2.5–3 kg. The bone marrow is a concentration of stem cells, which are the ancestors of all the blood cells we need.

Approximately 50% of the main weight of the bone marrow is the accumulation of hematopoietic vessels, which provide the delivery of oxygen and necessary tissues to the tissues. chemical compounds. The porous structure of the vascular wall creates the conditions for the penetration of nutrients.

There are two different types of bone marrow - red and yellow, between which there is no clearly defined border. The basis of the red bone marrow is hematopoietic tissue, and the yellow one is fatty. In the red brain, the formation of blood cells, monocytes and B-lymphocytes is carried out. The yellow brain is not involved in the formation of blood cells, but in some situations (for example, with blood loss), small foci of hematopoiesis may appear in it.

Over the years, the volume of red bone marrow in bone tissue decreases, and yellow, on the contrary, increases. This is due to the fact that from the moment of puberty to old age, the processes of hematopoiesis begin to steadily fade away.

thymus

The thymus (thymus gland) is located in the middle of the chest, in the retrosternal space. The shape of the thymus is a bit like a fork with two prongs (hence the name - the thymus gland). At the time of birth, the weight of the thymus is 10-15 grams. In the first three years of life, the thymus gland grows extremely rapidly.

From the age of three to twenty years, the thymus mass remains the same and is about 26-29 grams. Then the involution (reverse development) of the organ begins. In older people, the mass of the thymus does not exceed 15 grams. With age, the structure of the thymus also changes - the thymus parenchyma is replaced by adipose tissue. In the elderly, this organ is 90% fatty.

The thymus gland has a bipartite structure. The upper and lower lobes of the gland are different size and form. Outside, it is covered with a connective tissue capsule. Connective tissue penetrates into the thymus, thereby dividing it into lobules. In the gland, a cortical layer is isolated, in which growth and “inoculation of working skills” take place in lymphocytes “born” in the bone marrow, and a medulla, the bulk of which is made up of glandular cells.

The process of "achieving maturity" by lymphocytes, which occurs in the thymus gland, is extremely significant for immunity and the human immune system. At infants with congenital defects of the thymus - underdevelopment or complete absence of this organ, impaired functional development the entire lymphatic system, so life expectancy with this pathology rarely exceeds 12 months.

Spleen

The spleen is located on the left under the ribs and has the shape of a flattened and elongated hemisphere. In adults, the length of the spleen is 10-14 cm, the width is 6-10 cm, and the thickness is 3-4 cm. The weight of the organ in a man aged 20-40 is 192 grams, in a woman - 153 grams. Scientists have found that from 750 to 800 ml of blood passes through the spleen every day. Here, the formation of class M and J immunoglobulins occurs as a reaction to the intake of antigens, and the synthesis of factors that stimulate phagocytosis by leukocytes and macrophages. In addition, the spleen is a biological filter for xenobiotics, dead blood cells, bacteria and microflora.

The lymph nodes

Lymph nodes act as biological filters in the body for the lymphatic fluid flowing through them. They are located along the flow of lymph through the lymphatic vessels from organs and tissues.

As a rule, lymph nodes lie in groups of two to several dozen nodes. Outside, the lymph nodes are protected by a capsule, inside which there is a stroma, consisting of reticular cells and fibers. Each lymph node includes from 1-2 to 10 small arteries that supply it with blood.

Islands of lymphatic tissue

Accumulations of lymphatic tissue located in the mucous membrane are also called lymphoid formations. Lymphoid formations are found in the pharynx, esophagus, stomach, intestines, respiratory organs, urinary tract.

Islets of lymphatic tissue in the pharynx are represented by 6 tonsils of the lymphoid pharyngeal ring. The tonsils are a powerful accumulation of lymphoid tissue. From above, they are uneven, which contributes to the retention of food and creates a breeding ground for the reproduction of bacteria, which, in turn, serves as a trigger for triggering immunological processes.

Lymphoid formations of the esophagus are lymph nodes deep in the folds of the esophagus. The task of the lymphoid formations of the esophagus is to protect the walls of this organ from foreign tissue and antigens that enter the body with food.

Lymphoid formations of the stomach are represented by B- and T-lymphocytes, macrophages and plasma cells. The lymphatic network of the stomach begins with lymphatic capillaries located in the mucous membrane of the organ. Lymphatic vessels depart from the lymphatic network, passing through the thickness of the muscle layer. Vessels from the plexuses lying between the muscle layers flow into them.

Islets of the lymphatic tissue of the intestine are represented by Peyer's patches - group lymph nodes, single lymph nodes, diffusely located lymphocytes and the lymphatic apparatus of the appendix.

The appendix or appendix is an appendage of the caecum and extends from its posterolateral wall. The thickness of the appendix contains a large amount of lymphoid tissue. It is believed that the lymphoid tissue of the appendix is from 1% of all human lymphoid tissue. The cells produced here protect the body from foreign substances that enter the digestive tract along with food.

Lymphoid formations of the respiratory system are accumulations of lymphatic tissue in the mucous membrane of the larynx, trachea and bronchi, as well as lymphoid cells diffusely located in the mucous membrane of the respiratory apparatus, called bronchial-associated lymphoid tissue. Lymphoid formations of the respiratory system protect the body from foreign particles that enter the respiratory system along with the air flow.

Lymphoid formations of the urinary tract are located in the walls of the ureters and Bladder. According to scientists, in infancy, the number of lymph nodes in the ureters ranges from 2 to 11, and then increases to 11-14. In old age, the number of lymph nodes again decreases to 6-8. Lymph nodes in the urinary tract protect us from foreign substances that enter the body from the outside in an ascending way.

How the immune system works

Immunity and the immune system of the human body is a highly accurate, well-coordinated mechanism that fights bacteria and xenobiotics. All organs of the human immune system work together, complementing each other. The main task of the immune system and the immune system is the recognition, destruction and removal from the body of harmful infectious agents and foreign substances, as well as the resulting mutated cells and decay products.

All substances unknown to the body that penetrate into it are called antigens. After the immune system detects the antigen and recognizes it, it begins to produce special cells - antibodies that bind the antigen and destroy it.

In humans, there are two types of immune defense - innate and acquired immunity. Innate resistance is a very ancient protective system that all living beings have. Innate immunity is aimed at destroying the cell membrane of an intruder that has entered the body.

If the destruction of the foreign cell did not occur, another line of defense comes into play - acquired immunity. The principle of its operation is as follows: when a bacterium or a foreign substance enters the human body, leukocytes begin to produce antibodies. These antibodies are strictly specific, that is, they correspond to the substance that has entered the body as two neighboring puzzles to each other. Antibodies bind and destroy the antigen, thereby protecting our body from disease.

Allergy

In some situations, the immune system human body react violently to safe factors environment. This condition is called an allergy. Substances that provoke the manifestation of allergies are called allergens.

Allergens are divided into external and internal. External allergens are those that enter the body from the environment. It can be certain types of food, mold, wool, pollen, etc. An internal allergen is our own tissue, usually with altered properties. This happens, for example, with bee stings, when the affected tissues begin to be identified as foreign.

When an allergen enters the human body for the first time, it usually does not cause any external changes, however, the processes of production and accumulation of antibodies take place. If the allergen enters the body again, an allergic reaction begins, which can proceed in different ways: in the form of skin rashes, tissue swelling, or an asthma attack.

Why doesn't everyone get allergies? There are several reasons for this. First, heredity. Scientists have proven that the tendency to develop allergies is passed from generation to generation. At the same time, if the mother is ill with allergies, then the child will develop an allergy with a probability of 20-70%, and if the father - only 12-40%.

The likelihood of an allergy in a child is especially high if both parents suffer from this disease. In this case, the allergy will be inherited with a probability of 80%. In addition, allergic reactions are more likely to occur in people who have been sick a lot in childhood.

Another factor contributing to the occurrence of allergies in humans is the unfavorable ecological situation in the area of residence. Scientists have proven that in areas with polluted air, the number of allergic children is significantly greater than in areas with favorable ecology. This is especially true for such allergic diseases as bronchial asthma and allergic rhinitis (hay fever).

And there is a scientific explanation for this: microscopic particles suspended in polluted air irritate the epithelial cells of the respiratory mucosa, thereby activating them and promoting the release of anti-inflammatory cytokines.

Thus, allergic reactions are another manifestation of the immune system, the very case when, taking care of our safety, the immune system, like a loving parent, shows excessive zeal.

Immunity is the resistance of the human body to various harmful factors, such as viruses or bacteria. This definition is short, but it is accessible what it is - immunity. This term was first used by Louis Pasteur and Ilya Mechnikov and. They investigated the body's resistance to various infections. In our time, it is known that the body destroys various genetically foreign objects for it, not only pathogens of infectious diseases. The exception is female organisms in mammals during pregnancy, although there are situations when the fetus is rejected by the mother's body due to a malfunction of her immune system.

Louis Pasteur

The body's resistance is classified by scientists. Thus, immunity can be species-specific (characteristic of all individuals of a certain species, developed as a result of evolution, phylogeny) or individual (it is inherent in a certain individual, that is, such immunity is developed during life). Types of immunity:

depending on the number of owners. Absolute species immunity means that one or another biological species is completely resistant to pathogens of certain diseases, and with relative immunity, the disease is possible, although in rare cases. For example, fish never get rabies, although all warm-blooded creatures are more or less susceptible to this infection. At the same time, cats get sick with it more often than rabbits. It turns out that fish have absolute immunity against rabies, while rabbits have relative immunity (they rarely, but can get rabies).
According to the time of occurrence in a person or animal. If it appeared before the first contact with a virus or bacterium, this is innate immunity. The acquired resistance of the body is developed as a result of the fact that a person has already suffered infectious disease(natural immunity) or vaccinated (artificially).
According to the method of receipt. Artificial or natural acquired immunity can be active (it must be developed after illness or vaccination using an infectious agent) or passive (if a person was injected with serum with antibodies or the baby received them with mother's milk).

Human immune system

The protective function of the body is provided by certain human organs, the totality of which is called the immune system. It includes:

Lymphocytes are a type of leukocytes (white blood cells). These cells produce antibodies (this is humoral immunity, that is, the body is protected by a cell product located in the intercellular space) and destroy bacteria (such immunity is called cellular immunity, because it involves contact of the defender cell with the infectious agent).
T-lymphocytes are cells that recognize and destroy cells affected by viruses. This phenomenon is called phagocytosis. Other phagocytes (cells that absorb infectious agents and other foreign objects) of the human body are neutrophils, macrophages, monocytes, mast and dendritic cells.
NK lymphocytes are cells that destroy cancerous and virus-infected cells.
B-lymphocytes are lymphocytes that provide humoral immunity. They develop into plasma cells, cells in the human body that produce antibodies.
Cytokines are cells that synthesize certain substances that have biological activity. They can mediate between various types immunocompetent cells or take a direct part in protecting the body from infections.
Antigen-presenting cells (M-cells located in the lymphatic follicles of the food tube, process cells in the lymph nodes and spleen, macrophages, thymus epithelial cells, Langerhans cells).
Diffuse lymphoid tissue is the tissues of the thickness of the mucous membranes of the respiratory, genitourinary and digestive systems.
The lymphoid organs of immunity are the spleen, tonsils (tonsils) and lymph nodes.
The thymus gland (thymus) is the organ responsible for the production of T-lymphocytes. The size of this gland decreases with age (from 15–17 cm in adolescents to 7–8 cm in the elderly). After the age of 60, it gradually ceases to function, as its cells are replaced by adipose tissue.
The bone marrow is the organ responsible for blood formation in the human body. It contains stem cells, which are cells that can develop into other types of cells. During fetal development, stem cells are produced not only by the bone marrow, but also by the liver, and after birth, exclusively by the bone marrow.
Lymph fluid (clear, located in the lymph nodes and contains lymphocytes).

Diseases of the human immune system

The main dysfunctions of the immune system are divided into 3 groups:

Insufficiency of immunity - immunodeficiency (sometimes primary - congenital and secondary - acquired).
The perversion of immune system reactions is called dysfunction.
Excessive body resistance - hyperfunction.

Congenital immunodeficiencies are usually associated with genetic disorders and appear in children and adolescents. These can be lesions of any part of the immune system. As a rule, they are detected by immunologists, focusing on the symptoms of the disease and immunogram data.

Also, sometimes immunity can decrease due to malnutrition (lack of vitamins and trace elements), poisoning, chronic diseases(diabetes, kidney and liver failure, intestinal problems), stress. Also at risk are smokers, alcoholics, drug addicts, as well as people whose work is associated with frequent trips to distant countries and climate change. Girls who follow the figure need to remember that excessive thinness also does not increase the body's resistance.

Prevention of diseases of the immune system

Of course, it is impossible to completely exclude the possibility of impaired immunity, but it is possible to reduce the risk of acquired autoimmune diseases. To do this, experts advise:

In addition, you need to take into account the peculiarities of your genetic health and, if it is known that in the family of a person there were people with congenital diseases of the immune system, consult a therapist and geneticist to prevent the appearance of their symptoms. Those who smoke or are fond of alcoholic beverages should part with bad habits. Drugs should be excluded even in thoughts, because they destroy all human organs. In addition, people who play sports and harden their bodies usually have a higher resistance to infections than those who do not.

Ways to improve immunity

If the patient's immunity has nevertheless decreased, despite the preventive measures taken, it is possible to correct the situation and develop a better body resistance to adverse factors:

babies need breast-feeding because breast milk contains some antibodies;
do the necessary vaccinations (in case of epidemics, trips to exotic countries, etc.);
enjoy some folk remedies(goat fat, decoctions of chamomile and rose hips, linden and mint teas, onion, lemon, garlic, honey);
in some cases, doctors recommend immunoglobulins and immunocorrectors (Tymogen-3 and Tsitovir are often prescribed for older people).

Concerning medicines that increase the body's resistance, self-treatment with them is fraught with a deterioration in well-being, so here you need expert advice. It is worth purchasing them only if the doctor strongly recommends using them.

Components of the immune system

The structure of the organs of the immune system is quite complex and is only slightly inferior to how the nervous system is built. Its central organs are:

Red and yellow bone marrow. Its purpose is to be responsible for the hematopoietic process. Spongy substances of short bones contain red brain. It is also found in the spongy components of flat bones. Tubular bones in their cavities contain a yellow brain. In children's bones, there is only red. This type contains stem cells.
Thymus (thymus). Located behind the chest. Represents 2 shares: with right side and from the left. Both lobes are divided into smaller lobules, containing the cortex at the edges and the medulla in the center. The basis of the thymus gland are epithelioreticulocytes. They are responsible for the formation of a network of T-lymphocytes, the production of thymosin and thymopoietin (bioactive components). Lymphocytes are produced by the cortical substance, then they enter the brain, and from there into the blood.

The immune system contains peripheral organs. Their total weight (both those and others) is about 1 kilogram.

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What organs are peripheral?

The immune system has 6 tonsils:

Palatine steam room. Located on both sides of the pharynx. It is an organ covered with several layers of squamous epithelium.
Tubal tonsil (also steam room). Its base is lymphoid tissue. Located in the region of the auditory tube. Surrounds the opening of the pharynx.
Pharyngeal tonsil (unpaired organ). Its location is the wall of the pharynx from above.
Lingual tonsil (also unpaired). The place of its localization is the region of the language root.

The following organs also belong to the peripheral part of the immune system:

lymph nodes. They are located in the following systems: digestion, respiration, urination. Forms a ball shape a large number lymphocytes. Protect the body from the ingress of foreign harmful substances. If an antigenic danger arises, then the process of formation of lymphocytes starts, since the centers of their reproduction are located in the nodules.
Lymphoid plaques. Their location is the small intestine. Consist of several nodules of the same name. These plaques do not allow foreign substances to enter the bloodstream or lymph. It is in the small intestine that there are especially many strangers, since the process of digestion of food takes place here.
Appendix (is a vermiform appendix). It contains a lot of lymphoid nodules. They lie close to each other. The process itself is located in the border zone between the small intestine and the large intestine. It is one of the main functions of the immune system.
The lymph nodes. They are located in places where lymph flows. In the lymph nodes, foreign substances and dead cells of the body are retained. There they are destroyed. Lymph nodes in the body are not located one at a time. Usually there are two or more.
Spleen. Its location is the abdominal cavity. The task of this important organ is to control blood and its composition. The spleen consists of a capsule with trabeculae extending from it. It also contains pulp, white and red pulp. The basis of the white is the lymphatic tissue, the red is the reticular stroma. 78% of the entire organ is given by nature to the red pulp, which contains many lymphocytes and leukocytes, as well as other cells.

All of them are located so that they surround the place where the mouth and nose cavities enter the pharynx. If foreign substances (from food or from inhaled air) try to enter the body, then it is in this place that lymphocytes await them.

The interaction of all organs presents a complex picture. Their coordinated work, as well as the structure and functions of the immune system, provide reliable protection organism.

Long before the baby is born, even in the womb, the formation of the child's immune system begins. In order for it to develop in the future, the child needs mother's milk. For the same purpose, an antigenic load is needed - the contact of the child's body with various microorganisms.

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What is the immune system responsible for?

The functions of the human immune system can be represented as the following algorithm:

recognize a foreign element;
destroy the alien;
provide maximum protection to your body.

In the body, nothing passes without a trace, including the immune response. The immune system at the first encounter with any foreign substance (infection, microbe, etc.) will definitely remember its properties. The next meeting with him affects him more effectively.

Bacteria appear in the life of the baby almost immediately after his birth. Many parents believe that the child should be as sterile as possible. But this opinion is wrong. Elementary Rules hygiene is necessary, but you should not go to extremes. Excessive sterility can prevent the infant's immune system from developing its properties. If the mother's milk contains a certain amount of bacteria, then you can not refuse it. The child's body must learn to deal with harmful substances. The function of the immune system is to fight various viruses and bacteria.

In most cases, she copes with them before they have time to show their negative impact on the human body, that is, a person does not even notice that not everything is in order in the body.

But if there are too many pathogenic substances, then not every immune system will be able to cope. There are also pathogens that, even in small quantities, are not subject to the best immunity. For example, cholera or chickenpox. A decrease in the functions of the immune system is manifested by frequent colds, chronic infections, and a constant temperature of 37-38 ° C. There are diseases, the peculiarities of which are that a person suffers from them only once in a lifetime. For example, measles. This is due to the immune system, which forms a stable immunity to the transferred disease.

The immune system is necessary for a person to protect the body from external foreign invasions, to control physiological responses organism and ensure normal functioning circulatory system. Our immune system quickly recognizes foreign agents that invade the human body and immediately turns on an adequate defensive response, the so-called immune response.

Foreign elements are called "antigens", and by their nature they can have the most various origins and structure: viruses, fungi, bacteria, plant pollen, house dust, chemical substances, transplanted tissues and organs - this list is very long. If the immune system works with disorders, then antigens can provoke serious human diseases and threaten his life.

In order to form an adequate immune response to the invasion of antigens, the immune (lymphatic) system includes many organs and specific cells that are part of it and are located throughout the body. The structure of the immune system is only slightly inferior in its complexity nervous system person.

The main organ of the human immune system is Bone marrow, which is responsible for hematopoiesis - produces red blood cells, platelets and white blood cells in exchange for dying and dying cells. There are yellow and red bone marrow, the total weight of which in the body of an adult reaches 2.5-3 kg. The location of the bone marrow is the large bones of the human skeleton (spine, tibia, pelvic bones, etc.).

Thymus gland or thymus Together with the bone marrow, it is the central organ of the immune system, consisting of immature and undifferentiated cells - stem cells that come to it from the bone marrow. In the thymus, maturation, differentiation of cells and the formation of T-lymphocytes, which are responsible for the reactions of cellular immunity, take place. The thymus gland is located behind the upper third of the sternum in the mediastinum between the right and left mediastinal pleura.

Produce lymphocytes and tonsils, which are located on back wall nasopharynx in its upper part. The tonsils are composed of diffuse lymphoid tissue that contains small sizes dense lymphoid nodules.

Spleen, one of the central organs of the immune system, is located in abdominal cavity in the zone of the left hypochondrium, which is projected at the level of the IX-XI ribs. The spleen has appearance slightly flattened elongated hemisphere. Arterial blood flows to the spleen through the splenic artery to purify the blood of foreign elements and remove old and dead cells.

Peripheral immune (lymphatic) system It is represented in human organs and tissues by an extensive system of lymphatic capillaries, vessels, and ducts. The lymphatic system works in close relationship with the circulatory system and is constantly in contact with the tissue fluid through which nutrients to the cells. Transparent and colorless lymph transports metabolic products into the blood through the lymphatic system and is the carrier of protective cells - lymphocytes, which are in direct contact with antigens.

The structure of the peripheral lymphatic system includes specific formations - The lymph nodes, which are maximally located in the human body, for example, in the inguinal region, in the area of \u200b\u200bthe armpit, at the base of the mesentery of the small intestine, and others. Lymph nodes are assigned the protective role of "filters", which boils down to the production of lymphocytes, immune bodies, and the destruction of pathogenic bacteria. Lymph nodes are the custodians of lymphocytes and phagocytes. They are responsible for the immune response and form an immune response.

Lymph is actively involved in the elimination of the inflammatory process and, and active participants in immune reactions are lymph cells - lymphocytes, which are divided into T-cells and B-cells.

B cells (B lymphocytes) produced and stored in the bone marrow. It is they who form specific antibodies, which are a "counterweight" to only one type of antigen. How many antigens enter the body, so many types of antibodies are formed to neutralize foreign agents during the immune response. B cells show their activity only against antigens that are located outside the cells and float freely in the blood.

source T-cells (T-lymphocytes) serves as the thymus gland. This type of lymphatic cells, in turn, is divided into T-helpers (T-helper cells) and T-suppressors. T-helpers play a leading role in the protective reaction of the body, coordinate the work of all immune cells. T-suppressors control the strength and duration of the immune response in order to slow down the immune response in time if the antigen is already neutralized, and the need for active work of the immune system no longer exists.

Lymphocytes are also secreted T-killers, which attach to damaged or infected cells in the human body in order to subsequently destroy them.

plays an important role in the development of the immune response phagocytes, which actively attack and destroy antigens. Among phagocytes, macrophage, which is called the "big destroyer", is of particular interest. It envelops and absorbs antigens or damaged cells, so that, having “digested” them, it finally breaks them down into their constituent parts.

Immune responses are based on the ability to recognize “self” and “foreign”. The immune reaction synthesizes specific antibody formations, which become the basis of humoral immunity, and sensitized lymphocytes provide cellular immunity. All immunocompetent cells necessarily participate in the inflammatory (immune) reaction and determine the nature and course of its course. In addition, immune cells control and regulate the processes of tissue regeneration after damage.

So, in response to the invasion of any antigen, the body responds with an immune response, which has two types of immune response, caused by two types of lymphocytes. Humoral immunity is formed by B-lymphocytes due to the formation of free antibodies circulating in the blood. This type of immune response is called humoral. Cellular immune response develops due to T-lymphocytes, which eventually form cell-mediated immunity. These two types of immune responses are involved in the destruction of foreign proteins that have invaded the body or formed by the tissues and organs themselves.

The humoral immune response is designed to eliminate foreign proteins with the help of antibodies circulating freely in the blood. B-lymphocytes, when they encounter an antigen, instantly recognize a foreign substance in it and immediately turn into cells that produce antibodies that are carried in the bloodstream and destroy “their” antigens on their way. Cells that produce antibodies are called plasma cells. The main area of their location is the spleen and bone marrow.

At its core, antibodies are Y-shaped protein formations that are able to attach to foreign proteins in a kind of “key-lock” mechanism. The top of the antibody, which has the shape of "V", is fixed on a foreign protein, and the lower part in the form of "I" in the form of a bridge is connected to the phagocyte. The phagocyte, in turn, removes the antigen-antibody complex from the body, turning on the appropriate destruction mechanism.

But, on their own, B-lymphocytes are not able to provide an adequate immune response. They come to the aid of T-lymphocytes, which trigger a cellular immune response that has its own characteristics. In some cases, B-lymphocytes, when they encounter an antigen, do not turn into plasma cells, but instead they send a signal to T-lymphocytes for help to fight foreign proteins. The T-lymphocytes that came to the rescue, when confronted with "outsiders", begin to produce specific chemicals called "lymphokines", which serve as a catalyst for activation a large number various immune cells. All cells, in turn, begin to actively divide and capture a foreign cell for its destruction. A feature of the cellular immune response is that antibodies do not take part in it.

The immune system is multifunctional and unique, it is characterized by the phenomenon of "memory", which provides an accelerated and stronger immune response when it encounters an antigen again. The secondary immune response is always more effective than the primary one. This effect is the basis for the formation of immunity and the meaning of vaccination.

The immune system- a complex of organs and cells, the task of which is to identify the causative agents of any disease. The ultimate goal of immunity is to destroy a microorganism, atypical cell, or other pathogen causing an adverse health effect.

The immune system is one of critical systems human body

Immunity is the regulator of two main processes:

1) he must remove from the body all the cells that have exhausted their resources in any of the organs;

2) to build a barrier to the penetration into the body of an infection of an organic or inorganic nature of origin.

As soon as the immune system recognizes the infection, it seems to switch to an enhanced mode of body defense. In such a situation, the immune system must not only ensure the integrity of all organs, but at the same time help them perform their functions, as in a state of absolute health. To understand what immunity is, you should find out what this protective system of the human body is. A set of cells such as macrophages, phagocytes, lymphocytes, as well as a protein called immunoglobulin - these are the components of the immune system.

More concisely the concept of immunity can be described as:

Immunity of the body to infections;

Recognition of pathogens (viruses, fungi, bacteria) and their elimination when they enter the body.

Organs of the immune system

The immune system includes:

Thymus (thymus gland)

The thymus is located in the upper part of the chest. The thymus gland is responsible for the production of T-lymphocytes.

Spleen

The location of this organ is the left hypochondrium. All blood passes through the spleen, where it is filtered, old platelets and red blood cells are removed. To remove a man's spleen is to deprive him of his own blood purifier. After such an operation, the body's ability to resist infections is reduced.

Bone marrow

It is located in the cavities of tubular bones, in the vertebrae and bones that form the pelvis. The bone marrow produces lymphocytes, erythrocytes, and macrophages.

lymph nodes

Another type of filter through which the lymph flow passes with its purification. Lymph nodes are a barrier to bacteria, viruses, cancer cells. This is the first obstacle that the infection encounters on its way. The next to fight the pathogen are lymphocytes, macrophages produced by the thymus gland and antibodies.

Types of immunity

Every person has two immunities:

specific immunity- this is the protective ability of the body, which appeared after a person suffered and successfully recovered from an infection (flu, chickenpox, measles). Medicine has in its arsenal of fighting infections a technique that allows you to provide a person with this type of immunity, and at the same time insure him from the disease itself. This method is very well known to everyone - vaccination. The specific immune system, as it were, remembers the causative agent of the disease and, in the event of a repeated attack of the infection, provides a barrier that the pathogen cannot overcome. Distinctive feature this type of immunity in the duration of its action. In some people, a specific immune system works until the end of their life, in others such immunity lasts for several years or weeks;
Nonspecific (innate) immunity- a protective function that begins to work from the moment of birth. This system passes the stage of formation simultaneously with intrauterine development of the fetus. Already at this stage, cells are synthesized in the unborn child that are able to recognize the forms of foreign organisms and develop antibodies.

During pregnancy, all cells of the fetus begin to develop in a certain way, depending on which organs will be formed from them. The cells seem to differentiate. At the same time, they acquire the ability to recognize microorganisms that are hostile in nature to human health.

The main characteristic of innate immunity is the presence of identifier receptors in cells, due to which the child perceives the mother's cells as friendly during the prenatal period of development. And this, in turn, does not lead to rejection of the fetus.

Prevention of immunity

Conditionally the whole complex preventive measures aimed at maintaining the immune system can be divided into two main components.

Balanced diet

A glass of kefir, drunk every day, will ensure normal intestinal microflora and eliminate the likelihood of dysbacteriosis. Enhance the effect of taking fermented milk products probiotics will help.

Proper nutrition is the key to strong immunity

Vitaminization

Regular consumption of foods high content vitamins C, A, E will provide an opportunity to provide yourself with good immunity. Citrus fruits, infusions and decoctions of wild rose, blackcurrant, viburnum are natural sources of these vitamins.

Citrus fruits are rich in vitamin C, which, like many other vitamins, plays a huge role in maintaining immunity.

You can buy the appropriate vitamin complex in a pharmacy, but in this case it is better to choose the composition so that it includes a certain group of trace elements, such as zinc, iodine, selenium, and iron.

overestimate role of the immune system impossible, so its prevention should be carried out regularly. Absolutely simple measures will help strengthen the immune system and, therefore, ensure your health for many years.

Sincerely,