The immune system is a collection of special tissues, organs and cells. This is a rather complicated structure. Next, 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 against various pathologies. The structure represents a barrier to infections of a fungal, viral, and bacterial nature. When a person has weak immunity or a malfunction occurs in his work, the probability of penetration of foreign agents into 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Historical reference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 leader Erlich. They investigated the existing defense mechanisms that are activated in the process of the body struggling with 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 the research. He developed a method of vaccination against a number of infections that are dangerous to humans. Initially, it was believed that the protective structures of the body direct their activity only to eliminate infections. However, subsequent studies by the Englishman Medawar proved that immune mechanisms work when any foreign agent invades, and indeed respond to any harmful interference. Today, the protective structure is mainly understood as the body's resistance to various kinds of antigens. In addition, immunity is a response of the body, aimed not only at the destruction, but also at eliminating the "enemies". If there were no protective forces in the body, then people would not be able to exist normally in environmental conditions. The presence of immunity allows coping with pathologies to survive 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. In humans, the thymus and bone marrow enter this part of the structure. The peripheral organs of the immune system are an environment where matured defense elements neutralize antigens. This part of the structure includes the lymph nodes, spleen, lymphoid tissue in the digestive tract. It was also found that the protective properties of the skin and neuroglia of the central nervous system. In addition to the above, there are also intra-barrier and barrier tissues and organs of the immune system. The first category includes skin. Barrier tissues and organs of the immune system: central nervous system, eyes, testes, fetus (during pregnancy), thymus parenchyma.
Structure Objectives
Immunocompetent cells in the lymphoid structures are predominantly lymphocytes. They recycle 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:
- The formation of conditions for the maturation of lymphocytes.
- The combination of populations of protective elements scattered throughout the body into an organ system.
- Regulation of the interaction of representatives of different classes of macrophages and lymphocytes in the implementation of protection.
- Ensuring timely transportation of elements to lesions.
Next, we consider in more detail the organs of the immune system.
Lymph node
This element is formed by soft tissues. The lymph node is oval. Its size is 0.2-1.0 cm. It contains immunocompetent cells in large numbers. The formation has a special structure, which allows you 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. In the lymph node, 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 main functions of the immune system of organs are indicated above. The spleen performs several other tasks. So, for example, in addition to the production of lymphocytes, blood is filtered in it, its elements are stored. It is here that the destruction of old and inferior cells occurs. The mass of the spleen is about 140-200 grams. Its lymphoid tissue is represented as a network of reticular cells. They are located around sinusoids (blood capillaries). Mostly the spleen is filled with red blood cells or white blood cells. These cells do not contact each other, vary in composition and quantity. With a reduction in smooth muscle capsule cords, a certain number of moving elements are pushed out. As a result, the spleen decreases in volume. The whole process is stimulated by the effects 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 the flat and tubular bones. The central organs of the immune system produce the necessary elements, which are then distributed over the zones of the body. Platelets, red blood cells, and white blood cells are produced in the bone marrow. Like other blood cells, they become mature after they acquire immune competence. In other words, receptors are formed on their membranes that characterize the similarity of an element with others similar to it. In addition to the bone marrow, organs of the immune system such as tonsils, Peyer's intestinal plaques, and thymus create the conditions for the acquisition of protective properties. In the latter, maturation of B-lymphocytes occurs, which have a huge amount (a hundred to two hundred times greater than that of T-lymphocytes) of microvilli. The blood flow is carried through vessels, which include sinusoids. Through them, not only hormones, proteins and other compounds penetrate the bone marrow. Sinusoids are channels of movement of blood cells. Under stress, the current decreases almost twice. When calming down, blood circulation rises to eight times the volume.
Peyer's Plaques
These elements are concentrated in the intestinal wall. They are presented in the form of accumulations 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. She has no color. A large number of lymphocytes are present in the fluid. These elements protect the body from disease.
Thymus
It is also called the thymus gland. In the thymus, the multiplication and maturation of lymphoid elements occurs. The thymus gland performs endocrine functions. Thymosin is released from its epithelium into the blood. In addition, the thymus is an immunoproducing organ. In it, the formation of T-lymphocytes occurs. This process occurs due to the division of elements that have receptors for foreign antigens that penetrate 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. Thymus is more active in young people and children than in older people. Over the years, the thymus gland decreases in size, and its work becomes not so fast. The suppression of T-lymphocytes occurs under stress. It may be, for example, about cold, heat, psycho-emotional stress, blood loss, starvation, excessive physical exertion. In people prone to stressful situations, immunity is weak.
Other items
The 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 lymphatic tissue also changes. The organs of the immune system, the scheme of which is located 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 scheme presented in the article shows that its structures are distributed throughout the body. The main defenders are lymphocytes. These cells 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 combination with other immune cells. All of them prevent the invasion of foreign substances in the body. At the initial stage, some kind of “training” of T-lymphocytes takes place to distinguish normal (intrinsic) proteins from foreign ones. This process occurs in the thymus in childhood, since it is during this period that the thymus gland is most active.
Body defense work
It should be said that the immune system was formed during a long evolutionary process. In modern people, this structure acts as a streamlined mechanism. It helps a person cope with the negative effects of environmental conditions. The structure's tasks include not only recognition, but also the elimination of foreign agents that have penetrated the body, as well as decay 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 define "enemies"? This process takes place at the gene level. It should be said here that each cell has its own genetic information that is 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 a trapped agent coincides with their own, then this is not an enemy. If not, then, accordingly, this is a foreign agent. In immunology, "enemies" are called antigens. After the detection of malicious elements, the protective structure includes its own mechanisms, and a "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 protection mechanisms. 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 taken as food, medicines, various chemicals (deodorants, perfumes, etc.). Internal allergens are 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 bites of bumblebees, bees, wasps and other insects. The development of an allergic reaction can occur sequentially or violently.
Baby's immune system
Its formation begins in the very first weeks of gestation. The 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 womb, his body is found with a small number of microorganisms. In this regard, its protective mechanisms are inactive. Before birth, the baby is protected from infections by the mother’s immunoglobulins. If any factors will adversely affect it, then the correct formation and development of the baby's protection may be impaired. After birth, in this case, the child may be sick more often than other children. But things can happen differently. For example, during pregnancy, the mother of the child can suffer an infectious disease. And the fetus can form a stable immunity to this pathology.
After birth, a huge number of microbes attack the body. 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, contacts with microorganisms are memorized. As a result, an "immunological memory" is formed. It is necessary for a more rapid manifestation of the reaction to already known antigens. It must be assumed 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 about the first four months of life. Over the next two months, proteins received from the mother are gradually destroyed. In the period from four to six months, the baby is most susceptible to disease. The intensive formation of the child’s immune system occurs up to seven years. In the process of development, the body gets acquainted with new antigens. The immune system throughout this period learns and prepares for adulthood.
How to help a fragile body?
Experts recommend taking care of the baby’s immune system before birth. This means that the expectant mother needs to strengthen her protective structure. In the prenatal period, a woman needs to eat properly, take special trace elements 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 for at least 4-5 months. With milk, protective elements penetrate the baby's body. During this period, they are very important for immunity. A child can even instill milk in a spout during an influenza epidemic. It contains a lot of useful compounds and will help the baby cope with negative factors.
Additional methods
Training your immune system can be done in a variety of ways. The most common are hardening, massage, gymnastics in a well-ventilated area, sun and air baths, swimming. There are also various remedies for immunity. One of them is vaccination. 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, Abrizol, Prodigiosan), leukopoiesis stimulants - Methyluracil, Pentoxyl, microbial immunostimulants - Prodignozan, Pyrogenal , "Bronchomunal", immunostimulants of plant origin - tincture of lemongrass, eleutherococcus extract, vitamins and many others. other
Only an immunologist or pediatrician can prescribe these funds. Self-administration of drugs of this group is highly not recommended.