Immune system -- system organ system, which exists in vertebrates and includes organs and tissues that protect the body from disease by identifying and destroying tumor cells and pathogens.
Immunity(lat. immunitas- liberation, getting rid of something) - insensitivity, resistance of the body to infections and invasions of foreign organisms (including pathogens), as well as the effects of foreign substances with antigenic properties. Immune reactions also occur against the body’s own cells that are antigenically altered.
Structure and composition of the immune system. The human immune system includes central authorities- bone marrow and thymus gland (thymus) - and peripheral - spleen, lymph nodes, lymphoid tissue. These organs produce several types of cells, which supervise the constancy of the cellular and antigenic composition of the internal environment.
The main cells of the immune system are phagocytes And lymphocytes (B and T lymphocytes). They circulate through the bloodstream and lymphatic system, some of them can penetrate into tissues. All cells of the immune system have certain functions and work in a complex interaction, which is ensured by the production of special biologically active substances - cytokines . You've probably heard names like interferons , interleukins and the like.
Lymphocytes produce specific proteins ( antibodies ) - immunoglobulins , interacting with certain antigens and connecting them. Antibodies neutralize the activity of poisons and microbes, making them more accessible to phagocytes.
The immune system “remembers” those foreign substances that it has encountered and reacted to at least once. The formation of immunity to “foreign” agents and tolerance to one’s own biological active substances and increased sensitivity to allergens. Normally functioning the immune system doesn't respond to internal factors and, at the same time, rejects foreign influences on the body. It forms immunity - anti-infective, transplantation, anti-tumor. Immunity protects the body from infectious diseases, frees it from dead, degenerated and foreign cells. Immune reactions cause rejection of transplanted organs and tissues. With congenital or acquired defects of the immune system, diseases arise - immunodeficiency, autoimmune or allergic, caused by hypersensitivity body to allergens .
Types of immunity . Distinguish between natural and artificial immunity
A person is already immune to many diseases from birth. This immunity is called congenital . For example, people do not get sick from animal plague because their blood already contains ready-made antibodies. Innate immunity is inherited from parents. The body receives antibodies from the mother through the placenta or mother's milk. Therefore, children who are on artificial feeding, weakened immunity. They are more susceptible infectious diseases and are more likely to suffer from diabetes. Innate immunity lasts throughout life, but it can be overcome if the doses of the infecting agent increase or the body’s protective functions weaken.
In some cases, immunity occurs after past diseases. This acquired immunity . Having been ill once, people become immune to the pathogen. Such immunity can last for decades. For example, after measles, lifelong immunity remains. But with other infections, for example, influenza, sore throat, immunity does not last long, and a person can suffer from these diseases several times during his life. Innate and acquired immunity are called natural.
The main function of the immune system is to control the qualitative constancy of the genetically determined cellular and humoral composition of the body.
The immune system provides:
- -Protection of the body from the introduction of foreign cells and from modified cells that have arisen in the body (for example, malignant);
- - destruction of old, defective and damaged own cells, as well as cellular elements, not typical for this phase of development of the organism;
- -neutralization with subsequent elimination of all high-molecular substances of biological origin that are genetically foreign to a given organism (proteins, polysaccharides, lipopolysaccharides, etc.).
The immune system consists of central (thymus and bone marrow) and peripheral (spleen, lymph nodes, lymphoid tissue accumulations) organs in which lymphocytes differentiate into mature forms and the immune response occurs.
The functioning basis of the immune system is a complex complex of immunocompetent cells (T-, B-lymphocytes, macrophages).
Specific immune system , or as it is also called acquired, is developed gradually. The body gradually learns to distinguish “friends” from “strangers” thanks to immunological memory. This process is only possible through contact with bacteria, viruses and microorganisms. This protection is formed by two very important and closely related factors - cellular (T- and B-lymphocytes) and humoral (immunoglobulins - antibodies). The cellular factor remembers the foreign substance, and when encountered again, quickly and effectively destroys it - this is immunological memory. This is exactly how vaccinations work - a strain of the virus is purposefully introduced into the body so that the T- and B-lymphocytes remember the virus and, when they encounter it again, quickly destroy it. T-lymphocytes destroy the virus on their own, and B-lymphocytes secrete special antibodies - immunoglobulins. You've probably seen them more than once in test results - they come in 5 types: IgE, IgA, IgG, IgM, IgD.
Human immunity is a state of immunity to various infectious and generally foreign organisms and substances to the human genetic code. The body's immunity is determined by the state of its immune system, which is represented by organs and cells.
Organs and cells of the immune system
Let's dwell here briefly, since this is purely medical information, unnecessary to the common man.
Red bone marrow, spleen and thymus (or thymus) – central organs of the immune system
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The lymph nodes and lymphoid tissue in other organs (for example, in the tonsils, in the appendix) is peripheral organs of the immune system
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Remember: tonsils and appendix are NOT unnecessary organs, but very important organs in the human body.
The main task of the human immune system is to produce various cells.
What types of immune system cells are there?
1) T lymphocytes. They are divided into various cells - T-killers (kill microorganisms), T-helpers (help to recognize and kill microbes) and other types.
2) B lymphocytes. Their main task is the production of antibodies. These are substances that bind to the proteins of microorganisms (antigens, that is, foreign genes), inactivate them and are removed from the human body, thereby “killing” the infection inside the person.
3) Neutrophils. These cells devour the foreign cell, destroy it, and are also destroyed. As a result, purulent discharge appears. A typical example of the work of neutrophils is an inflamed wound on the skin with purulent discharge.
4) Macrophages. These cells also devour microbes, but are not destroyed themselves, but destroy them in themselves, or pass them on to T-helper cells for recognition.
There are several other cells that perform highly specialized functions. But they are of interest to specialist scientists, while the types listed above are sufficient for the common man.
Types of immunity
1) And now that we have learned what the immune system is, that it consists of central and peripheral organs, of various cells, now we will learn about the types of immunity:
- cellular immunity
- humoral immunity.
This gradation is very important for any doctor to understand. Since many medications act on either one or the other type of immunity.
Cellular is represented by cells: T-killers, T-helpers, macrophages, neutrophils, etc.
Humoral immunity is represented by antibodies and their source – B-lymphocytes.
2) The second classification of species is based on the degree of specificity:
Nonspecific (or congenital) - for example, the work of neutrophils in any inflammatory reaction with the formation of purulent discharge,
Specific (acquired) - for example, the production of antibodies to the human papillomavirus, or to the influenza virus.
3) The third classification is types of immunity associated with human medical activities:
Natural – resulting from a human illness, for example, immunity after chickenpox,
Artificial - resulting from vaccinations, that is, the introduction of a weakened microorganism into the human body, in response to this the body develops immunity.
An example of how immunity works
Now let's look at a practical example of how immunity is developed to human papillomavirus type 3, which causes the appearance of juvenile warts.
The virus penetrates into microtrauma of the skin (scratches, abrasions) and gradually penetrates further into the deeper layers of the surface layer of the skin. It was not present in the human body before, so the human immune system does not yet know how to react to it. The virus integrates into the gene apparatus of skin cells, and they begin to grow incorrectly, taking on ugly forms.
This is how a wart forms on the skin. But this process does not bypass the immune system. The first step is to turn on T-helpers. They begin to recognize the virus, remove information from it, but cannot destroy it themselves, since its size is very small, and the T-killer can only kill larger objects such as microbes.
T-lymphocytes transmit information to B-lymphocytes and they begin to produce antibodies that penetrate through the blood into skin cells, bind to virus particles and thus immobilize them, and then this entire complex (antigen-antibody) is eliminated from the body.
In addition, T lymphocytes transmit information about infected cells to macrophages. They become active and begin to gradually devour the changed skin cells, destroying them. And in place of the destroyed ones, healthy skin cells gradually grow.
The entire process can take from several weeks to months or even years. Everything depends on the activity of both cellular and humoral immunity, from the activity of all its links. After all, if, for example, at some point in time, at least one link - B-lymphocytes - drops out, then the entire chain collapses and the virus multiplies unhindered, penetrating into more and more new cells, contributing to the appearance of more and more warts on the skin.
In fact, the example presented above is only a very weak and very accessible explanation of the functioning of the human immune system. There are hundreds of factors that can turn on one mechanism or another, speeding up or slowing down the immune response.
For example, the body's immune response to the influenza virus occurs much faster. And all because it tries to invade the brain cells, which is much more dangerous for the body than the effect of the papillomavirus.
And another clear example of how the immune system works - watch the video.
Good and weak immunity
The topic of immunity began to develop in the last 50 years, when many cells and mechanisms of the entire system were discovered. But, by the way, not all of its mechanisms have yet been discovered.
For example, science does not yet know how certain autoimmune processes are triggered in the body. This is when the human immune system, for no apparent reason, begins to perceive its own cells as foreign and begins to fight them. It’s like in 1937 – the NKVD began to fight against its own citizens and killed hundreds of thousands of people.
In general, you need to know that good immunity- This is a state of complete immunity to various foreign agents. Outwardly, this is manifested by the absence of infectious diseases and human health. Internally, this is manifested by the full functionality of all parts of the cellular and humoral components.
Weak immunity is a state of susceptibility to infectious diseases. It manifests itself as a weak reaction of one or another link, loss of individual links, inoperability of certain cells. There can be quite a few reasons for its decline. Therefore, it must be treated by eliminating all possible reasons. But we’ll talk about this in another article.
The immune system– a complex of organs and cells whose task is to identify the causative agents of any disease. The ultimate goal of immunity is to destroy the microorganism, abnormal cell, or other pathogen causing negative impact on human health.
The immune system is one of the most important systems of the human body.
Immunity is a regulator of two main processes:
1) he must remove from the body all cells that have exhausted their resource in any of the organs;
2) build a barrier to the penetration of infections of organic or inorganic origin into the body.
As soon as the immune system recognizes the infection, it switches to an enhanced mode of protecting the body. In such a situation, the immune system must not only ensure the integrity of all organs, but also help them perform their functions, as in a state of absolute health. To understand what immunity is, you need to 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.
In a more condensed formulation concept of immunity can be described as:
The body's immunity to infections;
Recognition of pathogens (viruses, fungi, bacteria) and elimination of them when they enter the body.
Immune system organs
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 and old platelets and red blood cells are removed. To remove a person'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 found 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 and is cleaned. Lymph nodes are a barrier to bacteria, viruses, and cancer cells. This is the first obstacle that the infection encounters on its way. The next to enter the fight against the pathogen are lymphocytes, macrophages produced by the thymus gland and antibodies.
Types of immunity
Any person has two immunities:
- Specific immunity is a protective ability of the body that appears after a person has suffered and successfully recovered from an infection (flu, chickenpox, measles). Medicine has in its arsenal of fighting infections a technique that makes it possible to provide a person with this type of immunity, and at the same time insure him against 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, when the infection attacks again, provides a barrier that the pathogen cannot overcome. Distinctive feature of this type of immunity in the duration of its action. Some people have a specific immune system that lasts until the end of their lives, while others have such immunity for several years or weeks;
- Nonspecific (innate) immunity– a protective function that begins to work from the moment of birth. This system goes through the formation stage simultaneously with intrauterine development fetus Already at this stage, the unborn child synthesizes cells that are able to recognize the forms of foreign organisms and produce antibodies.
During pregnancy, all fetal cells begin to develop in a certain way, depending on what organs will be formed from them. The cells seem to differentiate. At the same time, they gain the ability to recognize microorganisms that are hostile by nature to human health.
Main characteristic innate immunity is the presence of identifier receptors in cells, thanks to which the child during the intrauterine period of development perceives the mother’s cells as friendly. And this, in turn, does not lead to fetal rejection.
Prevention of immunity
Conditionally the whole complex preventive measures, aimed at preserving 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 it fermented milk products Probiotics will help.
Proper nutrition is the key strong immunity
Fortification
Regular consumption of foods with a high content of vitamins C, A, E will provide an opportunity to provide for yourself good immunity. Citrus fruits, rosehip infusions and decoctions, black currants, 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 corresponding vitamin complex in the pharmacy, but in this case it is better to choose the composition so that it includes a certain group of microelements, such as zinc, iodine, selenium, iron.
Overestimate role of the immune system impossible, so its prevention should be carried out regularly. Absolutely simple measures will help strengthen your immune system and, therefore, ensure your health for many years.
Sincerely,
The body's resistance to the effects of physical, chemical and biological pathogenic factors that can cause disease is called - resistance body. There are nonspecific and specific resistance.
Nonspecific resistance is provided by barrier functions, phagocytosis and the content in the body of special biologically active, bactericidal complement substances: lysozyme, properdin, interferon.
Specific resistance the organism is determined by the species and individual characteristics of the organism when it is exposed to both active (administration of vaccines or toxoids) and passive (administration of immune serums) immunization against pathogens of infectious diseases.
The organs of the immune system are divided into central and peripheral. TO central authorities include the thymus gland (thymus), bone marrow, and Peyer's patches, in which lymphocytes mature. Lymphocytes enter the blood and lymph and colonize peripheral organs : spleen, lymph nodes, tonsils and accumulations of lymphoid tissue in the walls of the hollow internal organs of the digestive, respiratory systems and genitourinary apparatus.
There are two main forms of immune defense: humoral and cellular immunity.
Humoral immunity.
This is a defense against the majority bacterial infections and neutralizing their toxins. It is carried out B lymphocytes , which are formed in the bone marrow. They are the predecessors plasma cells- cells that secrete either antibodies or immunoglobulins. Antibodies or immunoglobulins have the ability to specifically bind antigens and neutralize them.
Antigens- These are foreign substances, the introduction of which into the body causes an immune response. Antigens can be viruses, bacteria, tumor cells, unrelated transplanted tissues and organs, high-molecular compounds (proteins, polysaccharides, nucleotides, etc.) that have entered another organism.
Cellular immunity.
This is protection against most viral infections, rejection of foreign transplanted organs and tissues. Cellular immunity is carried out
T-lymphocytes formed in thymus gland(thymus), macrophages and other phagocytes.
In response to an antigenic stimulus, T lymphocytes are transformed into large dividing cells - immunoblasts, which in the final stage of differentiation turn into killer cells (to kill), which have cytotoxic activity towards target cells.
Killer T cells destroy tumor cells, cells of genetically foreign transplants and mutated own cells of the body. In addition to killer cells, the T-lymphocyte population also contains other cells involved in the regulation of the immune response.
T helper cells (to help - help), interacting with B-lymphocytes, stimulate their transformation into plasma cells that synthesize antibodies.
T-suppressors (suppression) block T-helper cells, inhibit the formation of B-lymphocytes, which reduces the strength of the immune response.
T-amps - promote a cellular immune response.
T-differentiating cells - change the differentiation of hematopoietic stem cells in the myeloid or lymphoid directions.
Immunological memory T cells - T-lymphocytes stimulated by an antigen, capable of storing and transmitting information about a given antigen to other cells.
Leukocytes, passing through the wall of the capillaries, penetrate into those body tissues that are subject to the inflammatory process, where they capture and devour microorganisms, dead body cells and foreign particles. The Russian scientist I.I. Mechnikov, who discovered this phenomenon, called this process phagocytosis (from the Greek phago - devour and kytos - cell), and cells that devour bacteria and foreign particles are called phagocytes. Phagocyte cells are distributed throughout the body.
IMMUNITY(from Latin immunitas - liberation) is the innate or acquired immunity of the body to foreign substances or infectious agents that have penetrated into it.
Distinguish congenital and acquired (natural and artificial) immunity.
Innate immunity represents a person’s immunity to microorganisms that cause diseases. This is a species trait that is inherited. Species-specific innate immunity is the most durable form of immunity (canine distemper and other animal diseases).
Acquired Naturally or artificially, immunity is developed by the body itself during life and can be active or passive:
1. Acquired natural active immunity develops after an infectious disease (post-infectious). In this case, the body itself actively produces antibodies. This immunity is not inherited, but is very stable and can last for many years (measles, chickenpox)
2. Acquired natural passive immunity is caused by the transfer of antibodies from mother to child through the placenta or breast milk; the duration of this immunity does not exceed 6 months.
3. Acquired artificial active immunity , develops in the body after vaccination. Vaccines- preparations containing killed or weakened living microorganisms, viruses, or neutralized products of their vital activity - toxoids. As a result of the action of antigens on the body, antibodies are formed in it. During the process of active immunization, the body becomes immune to repeated administration of the corresponding antigen.
4. Acquired artificial passive immunity is created by introducing into the body immune sera obtained from the blood of a person who has suffered a given disease, or from the blood of an animal vaccinated with a certain vaccine and containing antibodies that can neutralize the corresponding pathogens. This form of immunity occurs quickly, a few hours after administration of the immune serum. The serum is administered to people who have been in contact with the patient, but have not themselves been vaccinated against this disease (measles, rubella, paratitis, etc.). After being bitten by an unfamiliar dog, an anti-rabies serum is given for 1 to 3 days.
Faculty Control
Department "Humanitarian and social disciplines"
by discipline Physical Culture
"The body's immune system
person"
Completed by: student Shundakova K.M.
Group ED20.1/B-12
Checked by Orlov A.N.
Moscow 2013
The immune system is a collection of organs, tissues and cells, the work of which is aimed directly at protecting the body from various diseases and to destroy foreign substances that have already entered the body.
This system is an obstacle to infections (bacterial, viral, fungal). When the immune system malfunctions, the likelihood of developing infections increases, which also leads to the development of autoimmune diseases, including multiple sclerosis.
Organs included in the human immune system: lymph glands (nodes), tonsils, thymus gland (thymus), bone marrow, spleen and lymphoid formations of the intestine (Peyer's patches). The main role is played by a complex circulation system, which consists of lymphatic ducts connecting the lymph nodes.
A lymph node is a soft tissue formation, oval in shape and 0.2 - 1.0 cm in size, which contains a large number of lymphocytes.
Tonsils are small collections of lymphoid tissue located on both sides of the pharynx. The spleen is very similar in appearance to a large lymph node. The functions of the spleen are varied, it is a filter for blood, a storage for blood cells, and the production of lymphocytes. It is in the spleen that old and defective blood cells are destroyed.
The thymus gland (thymus) is located behind the breastbone. Lymphoid cells in the thymus multiply and “learn.” In children and young people, the thymus is active; the older a person is, the less active the thymus becomes and decreases in size.
Bone marrow is soft, spongy tissue located inside tubular and flat bones. The main task of the bone marrow is the production of blood cells: leukocytes, erythrocytes, platelets.
Peyer's patches - This is a concentration of lymphoid tissue in the intestinal wall. The main role is played by the circulation system, consisting of lymphatic ducts that connect the lymph nodes and transport lymphatic fluid.
Lymphatic fluid (lymph) is a colorless liquid that flows through the lymphatic vessels; it contains many lymphocytes - white blood cells involved in protecting the body from disease.
Lymphocytes are figuratively speaking “soldiers” of the immune system; they are responsible for the destruction of foreign organisms or diseased cells (infected, tumor, etc.). The most important types of lymphocytes (B lymphocytes and T lymphocytes) work together with other immune cells and prevent foreign substances (infections, foreign proteins, etc.) from invading the body. At the first stage, the body “teaches” T-lymphocytes to distinguish foreign proteins from normal (its own) proteins of the body. This learning process takes place in the thymus gland in childhood, since at this age the thymus is most active. Then a person reaches adolescence, and the thymus decreases in size and loses its activity.
The immune system appeared along with multicellular organisms and evolved as an aid to their survival. It connects organs and tissues that guarantee the body’s protection from genetically foreign cells and substances that come from environment. In terms of organization and functioning mechanisms, it is similar to the nervous system.
Both systems are represented by central and peripheral organs that are capable of responding to different signals, have a large number of receptor structures, and specific memory.
The central organs of the immune system include the red bone marrow, and the peripheral organs include the lymph nodes, spleen, tonsils, and appendix.
The central place among the cells of the immune system is occupied by various lymphocytes. When in contact with foreign bodies, with their help, the immune system is able to provide different forms of immune response: the formation of specific blood antibodies, the formation of different types of lymphocytes.
The very concept of immunity was introduced into modern science by the Russian scientist I.I. Mechnikov and the German - P. Ehrlich, who studied the body's defense reactions in the fight against various diseases, primarily infectious ones. Their joint work in this area was even noted in 1908 Nobel Prize. The work of the French scientist Louis Pasteur, who developed a vaccination method against a number of dangerous infections, also made a great contribution to the science of immunology.
The word immunity comes from the Latin immunis, which means free from anything. At first it was believed that immunity protects the body only from infectious diseases. However, research by the English scientist P. Medawar in the mid-twentieth century proved that immunity provides protection in general from any foreign and harmful interference in the human body.
Currently, immunity is understood, firstly, as the body’s resistance to infections, and, secondly, as the body’s responses aimed at destroying and removing from it everything that is alien to it and poses a threat. It is clear that if people did not have immunity, they simply would not be able to exist, and its presence allows us to successfully fight diseases and live to old age.
The immune system has been formed over many years of human evolution and acts like a well-oiled mechanism and helps fight diseases and harmful environmental influences. Its tasks include recognizing, destroying and removing from the body both foreign agents penetrating from the outside, as well as decay products formed in the body itself (during infectious and inflammatory processes), as well as pathologically changed cells.
The immune system is able to recognize many “strangers”. Among them are viruses, bacteria, toxic substances of plant or animal origin, protozoa, fungi, and allergens. She includes among them the cells of one’s own body that have turned cancerous and therefore become “enemies.” Its main goal is to provide protection from all these “strangers” and preserve the integrity of the internal environment of the body, its biological individuality.
How is “enemies” recognized? This process occurs at the genetic level. The fact is that each cell carries its own genetic information, unique only to a given person (we can call it a mark). This is what the immune system analyzes when it detects penetration into the body or changes in it. If the information matches (the label is present), then it is yours; if it does not match (the label is missing), it means it is someone else’s.
In immunology, foreign agents are usually called antigens. When the immune system detects them, defense mechanisms immediately turn on, and the fight against the “stranger” begins. Moreover, to destroy each specific antigen, the body produces specific cells, they are called antibodies. They fit antigens like a key to a lock. Antibodies bind to the antigen and eliminate it - this is how the body fights the disease.
One of the immune reactions is allergy - a state of increased response of the body to allergens. Allergens are substances or objects that contribute to the appearance of allergic reaction in organism. They are divided into internal and external.
External allergens include some foods (eggs, chocolate, citrus fruits), various chemicals (perfumes, deodorants), and medications.
Internal allergens are the body’s own tissues, usually with altered properties. For example, with burns, the body perceives dead tissue as foreign and creates antibodies for them. The same reactions can occur with the bites of bees, bumblebees, and other insects. Allergic reactions develop rapidly or sequentially. When an allergen affects the body for the first time, antibodies with increased sensitivity to it are produced and accumulated. When this allergen enters the body again, an allergic reaction occurs, for example, skin rashes and various tumors appear.
