Organs of the immune system. Functions of the immune system

The immune system is a collection of special tissues, organs and cells. This is a rather complex structure. Further we will understand 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 extermination of foreign compounds that enter the body and protection from various pathologies. The structure is a barrier to infections of a fungal, viral, bacterial nature. When a person's immunity is weak or a malfunction occurs in his work, the likelihood of foreign agents entering the body increases. As a result, various diseases can occur.

Historical reference

The concept of "immunity" was introduced into science by the Russian scientist Mechnikov and the German figure Erlich. They investigated the existing protective mechanisms, which are activated in the process of fighting the organism with different pathologies. First of all, scientists were interested in the reaction to infection. In 1908, their work in the field of studying the immune response was marked by the Nobel Prize. In addition, a significant contribution to the research was made by the works of the Frenchman Louis Pasteur. He developed a method of vaccination against a number of infections that were dangerous to humans. Initially, there was an opinion that the protective structures of the organism direct their activity only to the elimination of infections. However, subsequent studies by the Englishman Medavar proved that immune mechanisms work when an alien agent invades, and generally reacts to any harmful interference. Today, the protective structure is mainly understood as the resistance of the organism to various antigens. In addition, immunity is the response of the body, aimed not only at destruction, but also at eliminating "enemies." If there were no protective forces in the body, then people could not normally exist in an environment. The presence of immunity allows, coping with pathologies, to live to old age.

Organs of the immune system

They are divided into two large groups. The central immune system is involved in the formation of protective elements. People in this part of the structure include the thymus and bone marrow. Peripheral organs of the immune system are an environment where ripe protective elements neutralize antigens. This part of the structure includes lymph nodes, spleen, lymphoid tissue in the digestive tract. It was also found that the skin and neuroglia of the central nervous system possess protective properties. In addition to the above, there are also intra-barrier and barrier tissues and immune system organs. The first category includes the skin. Barrier tissues and organs of the immune system: CNS, eyes, testes, fetus (in pregnancy), parenchyma of the thymus.

Structure tasks

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

• Formation of conditions for the maturation of lymphocytes.
• The combination of populations of protective elements scattered throughout the body into the organ system.
• Regulation of the interaction of representatives of different classes of macrophages and lymphocytes in the process of implementing protection.
• Ensuring the timely transportation of elements to the lesions.

Next, let us examine in more detail the organs of the immune system.

Lymph node

This element is formed by soft tissues. The lymph node has the shape of an oval. Its size is 0.2-1.0 cm. It contains immunocompetent cells in large quantities. Education has a special structure that allows to form a large surface for the exchange of lymph and blood flowing through the capillaries. The latter comes from the arteriol and leaves through the venule. In the lymph node, the cells are immunized and antibodies are formed. In addition, the formation filters foreign agents and fine particles. In the lymph nodes in each part of the body there is its own set of antibodies.

Spleen

Outwardly it resembles a large lymph node. The above are the main functions of the immune system of organs. The spleen performs some other tasks. So, for example, in addition to the production of lymphocytes, it filters the blood, its elements are stored. It is here that the old and inferior cells are destroyed. The weight of the spleen is about 140-200 grams. Her lymphoid tissue is represented as a network of reticular cells. They are located around the sinusoids (blood capillaries). In general, the spleen is filled with red blood cells or leukocytes. These cells do not contact each other, they vary in composition and quantity. With the reduction of smooth-muscle capsular strings, a number of mobile elements are ejected. As a result, the spleen decreases in volume. The whole process is stimulated by the action of norepinephrine and adrenaline. These compounds are distinguished 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 along the zones of the body. In the bone marrow, platelets, erythrocytes and leukocytes are produced. Similarly to other blood cells, they become mature after they acquire immune competence. In other words, on their membranes receptors are formed that characterize the similarity of the element with other similar ones. In addition to the bone marrow, such immune system organs as tonsils, peyer plaques of the intestine, thymus create conditions for acquiring protective properties. In the latter, maturation of B-lymphocytes, which have a huge amount (in hundred-two hundred times more than in T-lymphocytes), microvilli, occurs. Blood flow is carried out through vessels that include sinusoids. Through them, not only hormones, proteins and other compounds penetrate the bone marrow. Sinusoids are channels for the movement of blood cells. Under stress, the current is almost halved. When calming, the blood circulation rises to eightfold.

Peyer's Plaques

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 that connect the nodes. Through these channels, the liquid is transported. It has no color. A large number of lymphocytes are present in the fluid. These elements protect the body from diseases.

Thymus

It is called the thymus gland. In the thymus, reproduction and maturation of lymphoid elements occurs. The thymus gland performs endocrine functions. From its epithelium, thymosin is secreted into the blood. In addition, the thymus is an immuno-producing organ. It is the formation of T-lymphocytes. This process is due to the division of elements that have receptors to foreign antigens that enter the body in childhood. The formation of T-lymphocytes is carried out regardless of their number in the blood. Does not affect the process and 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 rapid. Suppression of T-lymphocytes occurs under stress. This can be, for example, cold, warmth, psychoemotional stress, blood loss, starvation, excessive physical exertion. In people who are exposed to stressful situations, the immunity is weak.

Other elements

The vermiform appendage also belongs to the organs of the immune system. It is also called the "intestinal amygdala". Under the influence of changes in the activity of the primary part of the colon, the volume of lymphatic tissue changes. The organs of the immune system, the scheme of which is located below, include tonsils as well. They are on both sides of the pharynx. Tonsils are represented by small clusters of lymphoid tissue.

The main defenders of the body

The secondary and central organs of the immune system are described above. The scheme presented in the article shows that its structures are distributed throughout the body. The main advocates are lymphocytes. These cells are responsible for the destruction of sick elements (tumor, infected, pathologically dangerous) or alien microorganisms. The most important are T- and B-lymphocytes. Their work is carried out in conjunction with other immune cells. All of them prevent the invasion of foreign substances into the body. At the initial stage there is a kind of "training" of T-lymphocytes to distinguish normal (own) proteins from foreign ones. This process occurs in the thymus in childhood, because it is during this period that the thymus gland is most active.

Work of body protection

It should be said that the immune system was formed during a long evolutionary process. In modern people, this structure acts as a well-functioning 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 penetrated into the body, as well as degradation products, pathologically changed elements. The immune system has the ability to detect a large number of foreign substances and microorganisms. The main goal of the structure is to preserve the integrity of the internal environment and its biological identity.

Recognition process

How does the immune system determine "enemies"? This process occurs at the gene 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 detection of the penetration into the body or changes in it. If the genetic information of the hit agent coincides with its own, then it is not the enemy. If not, then, accordingly, this is a foreign agent. In the immunology of "enemies" it is customary to call antigens. After the detection of malicious elements, the protective structure includes its mechanisms, the "struggle" 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 mechanisms of protection. This condition is characterized by increased response to allergens. These "enemies" include objects or compounds that adversely affect the body. Allergens are external and internal. The first include, for example, foods eaten, medicines, various chemicals (deodorants, perfumes, etc.). Internal allergens are the tissues of the body itself, usually with altered properties. For example, with burns, the protective system perceives dead structures as alien. In this regard, she begins to develop antibodies against them. Similar reactions can be considered as bites of bumblebees, bees, wasps and other insects. The development of an allergic reaction can occur consistently or violently.

Immune system of the child

Its formation begins already in the very first weeks of gestation. The child's immune system continues to develop after his birth. The main protective elements are laid in the thymus and bone marrow of the fetus. While the baby is in the womb, his body is met with a small number of microorganisms. In this regard, its protective mechanisms are inactive. Before birth, the child is protected from infections by the mother's immunoglobulins. If it is adversely affected by any factors, the proper formation and development of child protection can be disrupted. After birth in this case, a child can get sick more often than other children. But everything can happen in a different way. For example, during pregnancy, the mother of the child can suffer an infectious disease. And the fetus can develop a permanent 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 protective structures of the body undergo a kind of "training" in the recognition and destruction of antigens. Along with this, memorization of contacts with microorganisms takes place. As a result, "immunological memory" is formed. It is necessary for a more rapid reaction to already known antigens. We must assume that the immunity of the newborn is weak, he is not always able to cope with the danger. In this case, antibodies obtained in utero from the mother come to the rescue. They are present in the body for approximately the first four months of life. During the next two months, the proteins obtained from the mother are gradually destroyed. In the period from four to six months, the baby is most susceptible to disease. Intensive formation of the immune system of the child occurs up to seven years. In the process of development the organism gets acquainted with new antigens. During the entire period, the immune system is trained and prepared for adulthood.

How to help a fragile body?

Specialists recommend taking care of the immune system of the child even before his birth. This means that the future mother needs to strengthen its protective structure. In prenatal period, a woman needs to eat right, take special microelements and vitamins. Moderate physical activity is also important for immunity. The child in the first year of life must receive mother's milk. It is recommended to continue breastfeeding for at least 4-5 months. With milk, protective elements penetrate the baby's body. During this period they are very important for immunity. The child can even dig in the milk in the nose during the flu epidemic. It contains a lot of useful connections and will help the kid to cope with negative factors.

Additional Methods

Training of the immune system can be carried out in various ways. The most common are hardening, massage, gymnastics in a well-ventilated room, solar and air baths, swimming. There are also various means for immunity. One of them are vaccinations. They have the ability to activate protective mechanisms, stimulate the production of immunoglobulins. Thanks to the introduction of special sera, the memory of the body structures to the input material is formed. Another means for immunity is special drugs. They stimulate the activity of the protective structure of the body. These medicines are called immunostimulants. These are interferon preparations (Laferon, Reaferon), interferonogens (Poludan, Abrisol, Prodigiozan), leukopoiesis stimulants - Metiluracil, Pentoxil, immunostimulants of microbial origin - Prodignosan, Pyrogenal , "Bronhomunal", immunostimulants of plant origin - tincture of magnolia vine, eleutherococcus extract, vitamins and many others. Other

Only the immunologist or pediatrician can prescribe these funds. Self-administration of drugs of this group is not recommended.