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Composition of the immune system. Immune system, its structure, structure, functions

WHAT IS IMMUNITY?

Immunity- this is the protection of our body

The immune system protects our body from any genetically foreign invasion: microbes, viruses, protozoa, from decay products formed inside the body (during infectious and inflammatory processes) or from cells of our own body that have changed as a result of mutations and diseases. If immunity is good and the immune system notices an invasion from the outside or breakdowns within in time and reacts adequately to them, the person is healthy.

How does the immune system protect us from infections?

Resistance to infections is due to a number of defense mechanisms.

Any pathogens or any of their individual structures that reach the mucous membranes of the intestines, nasopharynx, lungs, or enter the body are “caught” by phagocytes.

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.

Innate immunity

Phagocytes (from the Greek phagein, “to eat” and “-cyte,” cell), guarding everything foreign, absorb this agent, digest and remove it. This process is called phagocytosis.

This is how it “starts” first line of defense- innate immunity. He and his cells take on most of the “attacks” of the microbial world.

During malfunctions of the immune system, there is a “recurrence” of infections, the reason for this is most often the “weakness” of the first line of defense associated with the process of phagocytosis.

Normally, molecules of the bacterial cell wall or minimal fragments are formed in our gastrointestinal tract when they are digested by phagocytes, and they keep the innate immune system in a natural “tone”; when the number of first defense cells - phagocytes - is quite sufficient, then they are fully prepared fight back new bacteria or cope with those that came earlier.

If the “removal” of the pathogen does not occur, it is the turn of a more subtly and long-tuned second line of defense—acquired immunity. When, during the course of an illness, antibodies and memory cells are formed in the body, which will help in the future to recognize the causative agent of this disease and cope with it faster and more effectively.

Strengthening the immune system during chronic infections is based on increasing the functionality of the innate immune system, starting with phagocytosis and further, activating all parts of the natural immune response.

Immunity accumulated throughout life after illnesses or vaccinations is called acquired.

But in protection against infections, the leading role is played by innate immunity, which directs the launch of acquired immunity and its subsequent work.

How does the immune system work?

The immune system begins to be created in the womb. For some time after birth, the child is protected by maternal immunity received from the mother through the placenta. When the baby is born, the most critical stage of immunity formation begins. The most important protection for a child after birth and support of his immunity is colostrum.

A DROP OF COLOSTRUM IS WORTH YOUR WEIGHT IN GOLD!

Only after being born, the child begins to receive the maximum possible maternal protection through feeding with colostrum. This stage is extremely important from the point of view of developing immunity in the child. Colostrum is necessary to create the basis for the newborn’s immunity. Colostrum contains more antibodies and blood cells than mature breast milk. It is colostrum that gives the newborn the first defense against most viruses and bacteria that he will encounter. The level of protective factors in colostrum is so high that it is considered not only as a food product, but as a healing agent. This is the first “vaccination” that tones the baby’s immune system.

Immune factors in colostrum play an important role in preparing the child’s digestive system for the feeding process. In 1989 transfer factor was detected in colostrum. It is produced by cells of the immune system in response to the appearance of any foreign agent in the body and transmits information about the foreigner to immune cells. As a result, immune cells are trained to recognize the enemy and destroy it.

Then acquired immunity begins to form. This happens during every contact with any pathogen, be it a microbe, allergen, bacteria, or others.

And for each virus and microbe there will be a different response, the immune system will remember it and, upon repeated contact, will meet it fully armed and reflect it.

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, ensuring its normal functioning.

Recognition of “enemies” occurs at the genetic level. Each cell carries its own genetic information, unique to that person. The immune system analyzes this genetic information, detecting foreign agents entering the body or changes in its cells. If the information matches, then the agent is one of our own; if it does not match, then the agent is a stranger.

Video from the Tsentrnauchfilm archive, 1987.

Despite the fact that the film was created almost 30 years ago, it has not lost its relevance.

He talks about the principles of the immune system, which remain the same to this day.

Immunity - where is it? (organs of the immune system)

The immune system plays an extremely important role in human life. It is a complex of organs and cells aimed at performing an immunological function, i.e. to protect the body from genetically foreign substances coming from outside or formed in the body itself.

The organs of the immune system include bone marrow, in which lymphoid tissue is closely related to hematopoietic tissue, thymus(thymus gland), tonsils, spleen, lymphoid nodes in the walls of the hollow internal organs of the digestive, respiratory systems and genitourinary apparatus.

Bone marrow and thymus are the central organs of the immune system, since lymphocytes are formed from bone marrow stem cells.

The thymus is responsible for the production of T-lymphocytes and the hormones thymosin, thymalin and thymopoietin. A little biology: T-lymphocytes are regulators of inflammation and immune reactions; they are the central link of the entire defense system of the human body. Thymosin is a hormone of the thymus gland, which is responsible for the maturation of these same T-lymphocytes. Thymalin is a hormone of the thymus gland, which is responsible for maintaining the functioning of the entire gland as a whole. Thymopoietin is a hormone produced by the thymus gland that is involved in the recognition of T lymphocytes.

Thymus (thymus gland)- a small organ, weighing about 35-37 grams. The growth of the organ continues until the onset of puberty. Then the process of involution begins and by the age of 75 the weight of the thymus is only 6 grams.

When the thymus function is impaired, the number of T-lymphocytes in the blood decreases, which causes a decrease in immunity.

Numerous lymph nodes lie on the routes of lymph from organs and tissues to the venous system. Foreign substances in the form of particles of dead cells, together with tissue fluid, enter the lymph flow, are retained and neutralized in the lymph nodes.

With age, as a result of adverse effects, the immune system ceases to cope with the function of control and timely destruction of pathological cells. As a result, changes accumulate in the body, which are expressed in the aging process and the formation of various chronic diseases.

The immune system suffers especially strongly from exposure to stress, poor environmental conditions, poor nutrition and the use of toxic medications.

Causes of decreased immunity

Factors that reduce the effectiveness of the immune system:

  • Ecology, environmental pollution;
  • Poor nutrition, fasting, adherence to strict diets;
  • Deficiency of vitamins and microelements;
  • Prolonged stress;
  • Excessive, exhausting physical activity;
  • Previous injuries, burns, surgeries;
  • Bad habits - smoking, alcohol, caffeine;
  • Uncontrolled use of drugs;
  • Irregular sleep and rest patterns.

Signs of defective immunity

Signs of problems in the immune system:

  • Fatigue, weakness, lethargy, weakness. Poor night sleep, feeling tired in the morning;
  • Frequent colds, more than 3-4 times a year;
  • The presence of furunculosis, herpes, purulent inflammation of the sweat glands;
  • Frequent stomatitis and other inflammatory diseases of the oral cavity;
  • Frequent exacerbations of sinusitis, bronchitis (lasting more than 2 weeks), etc.
  • Prolonged elevated subfebrile (37-38 degrees) temperature;
  • Disorders of the gastrointestinal tract, colitis, dysbacteriosis, etc.;
  • Persistent, difficult to treat infections of the urogenital tract (chlamydia, ureaplasmosis, mycoplasmosis, etc.).
  • The doctor called the disease you have “chronic” or “recurrent”;
  • You have developed allergic, autoimmune or cancer diseases.

What destroys our immunity?

But alas, an incorrect lifestyle, bad habits, overeating, physical inactivity, by the age of 20-30 bring a person to a catastrophic state of health. And thank God if a person remembers about his health and medicine earlier.

Almost every person sooner or later becomes a patient of some doctor or clinic. And, unfortunately, most patients practically do not participate in their own treatment and recovery, but seem to go “to slaughter”, taking all kinds of pills. It is interesting that the word “patient” translated from Latin means “obediently enduring, suffering.” In contrast to conventional medicine, the philosophy of healthy living requires that a person be an active participant in treatment and recovery, and not just a “sufferer.” In Chinese medicine, it is customary to begin “treatment” before a person feels unwell. A person essentially knows better than anyone what is happening to his body, knows where it all started, and therefore is able to analyze and change his lifestyle in order to recover. No matter how perfect medicine is, it will not be able to rid everyone of all diseases.

If you suspect that your immune system is weakened, make sure that the influence of factors that can reduce the effectiveness of your immune system is minimal. Don't let immunodeficiency conditions develop!

How to strengthen your immune system?

What's in your hands? Get involved in improving your overall health. Strengthens immunity:

  • Good food. The body must receive certain vitamins (A, C and others) and nutrients in sufficient quantities;
  • Healthy sleep;
  • Movement. All types of physical exercises: with a reasonable load - running, swimming, gymnastics, training on exercise machines, walking, hardening procedures - have the most beneficial effect on the functioning of the immune system;
  • Quitting smoking and alcohol;
  • Careful attitude towards your psyche and the psyche of people. Constantly being in a state of stress leads to extremely negative consequences. Try to avoid stressful situations or treat them more calmly;
  • Hygiene.

Maintain hygiene

Compliance with hygiene rules greatly reduces the likelihood of infection entering your body.

The usual ways for infectious agents to enter the body (if hygiene standards and rules are not observed) are such organs as:

  • mouth;
  • nose;
  • leather;
  • stomach.

Currently, many worthy and very useful developments have been created in the field of immunology. Such developments include immunomodulators, in particular transfer factors, which act comprehensively on the entire human immune system. Being an immunomodulator developed by nature itself, Transfer Factor has no age restrictions. Transfer factor, in addition to all that has been said, does not have any side effects; it is indicated for use even by newborn babies and pregnant women.

Be healthy and take care of yourself!

The human immune system plays an important role in the professional knowledge of a personal trainer, since often in his coaching practice he has to deal with the fact that excessive loads increase the impact of stress on the body, and aggressive environmental conditions contribute to the weakening of the immune system and the occurrence of diseases. A personal trainer must know and be able to explain not only what the immune system is, but also what is often the causative agent of the disease and by what means the body fights it.

The goal of the immune system is to completely rid the human body of foreign agents, which are often pathogens, foreign pathogens, toxic substances, and sometimes mutated cells of the body itself. The immune system has a large number of options for identifying and neutralizing foreign bodies. This process is called an immune response. All his reactions can be divided into congenital and acquired. A characteristic difference between them is that acquired immunity is highly specific in relation to specific types of antigens, which allows it to quickly and efficiently neutralize them upon repeated encounter. Antigens are molecules that are perceived as foreign agents that entail specific responses in the body. For example, if a person has had chickenpox, measles or diphtheria, he often develops lifelong immunity to these diseases.

Development of the immune system

The immune system consists of a large number of varieties of proteins, cells, organs and tissues, the process of interaction between which is extremely complex and occurs quite intensively. A prompt immune reaction allows one to quickly identify certain foreign substances or cells. The process of adaptation to working with pathogens contributes to the development of immunological memory, which subsequently helps to provide even better protection for the body the next time it encounters foreign pathogens. This type of acquired immunity is the basis for vaccination methods.

Structure of the human immune system: 1- Liver; 2- Portal vein; 3- Lumbar lymphatic trunk; 4- Caecum; 5- Vermiform appendix; 6- Inguinal lymph nodes; 7- Cervical lymphatic trunk; 8- Left venous angle; 9- Thymus gland; 10- Intrathoracic lymphatic duct; 11- Tank of milky juice; 12- Spleen; 13- Intestinal lymphatic trunk; 14- Lumbar lymphatic trunk; 15- Inguinal lymph nodes.

The human immune system is represented by a collection of organs and cells that perform immunological functions. First of all, leukocytes are responsible for implementing the immune response. The cells of the immune system are mostly derivatives of hematopoietic tissues. In the adult, the development of these cells originates in the bone marrow and only T lymphocytes differentiate within the thymus gland. Adult cells settle inside lymphoid organs and at the border with the environment, near the surface of the skin or on mucous membranes. Transport of immune system cells during immune activation is ensured by the lymphatic system. It realizes its function by introducing into the systemic circulation various molecules, liquids and infectious agents packaged in exosomes and vesicles.

Stages of immune defense

The immune system protects the body from infections in several stages, with each subsequent stage increasing the specificity of the protection. The simplest form of protection is physical barriers, the purpose of which is to prevent bacteria and viruses from entering the body. If the infectious agent does penetrate these barriers, the innate immune system then reacts to it. If the pathogen successfully overcomes the barrier of the innate immune system, the third barrier of defense is activated - the acquired immune system. This part of the immune system adapts its response during the infectious process to increase its recognition of foreign biological materials. This response persists after the pathogen is eliminated in the form of immunological memory. It enables the mechanisms of acquired immunity to develop a faster and stronger response with each subsequent encounter with this pathogen.

The flow pattern of blood, interstitial fluid and lymph in the body: 1- Right atrium; 2- Right ventricle; 3- Left atrium; 4- Left ventricle; 5- Aorta and arteries; 6- Blood capillary; 7- Tissue fluid; 8- Lymphatic capillary; 9- Lymphatic vessels; 10- Lymph nodes; 11- Veins of the systemic circulation, where lymph flows; 12- Pulmonary artery; 13- Pulmonary vein. I- Circulatory system; II- Lymphatic system.

Both innate and acquired immunity depend on the ability of the immune system to distinguish self from non-self molecules. In immunology, self-molecules mean those components of the body that the immune system can distinguish from foreign ones. Conversely, foreign refers to those molecules that are recognized by the immune system as foreign. One of many classes of foreign molecules is called antigens and is defined as substances that are able to bind to specific immune receptors and trigger an immune response.

Immune system barriers

Since the human body is in constant interaction with its environment, nature has made sure that the functioning of the defense mechanism occurs, among other things, through the respiratory, digestive and genitourinary systems. These systems can be divided into constantly operating and symptomatically activated (in response to intrusion). An example of a permanent defense system is the small hairs on the walls of the trachea, which are also called cilia. They make intense upward movements, due to which dust particles, pollen and other foreign objects are removed from the respiratory tract. Actions similar in purpose (removal of microorganisms) are carried out due to the washing action of tears and urine. Mucus, which is secreted in the respiratory and digestive systems, serves to bind and immobilize foreign bodies, objects and microorganisms. If the constantly operating defense mechanisms are not enough, “emergency” mechanisms of cleansing the body of pathogens, such as coughing, sneezing, vomiting and diarrhea, are activated.

Structure of the lymph node: 1- Capsule; 2- Sine; 3- Valve to prevent reverse flow; 4- Lymphatic nodule; 5- Cortex; 6- Gate of the lymph node. I- Afferent lymphatic vessels; II- Efferent lymphatic vessels.

In the genitourinary and gastrointestinal tracts there are biological barriers represented by friendly microorganisms - commensals. Non-pathogenic microflora that have adapted to living in these conditions competes with pathogenic bacteria for food and space, often changing living conditions, namely acidity or iron content. This greatly reduces the likelihood of pathogenic microbes reaching the quantities necessary for the development of pathology. There is quite convincing evidence that the introduction of probiotic flora, for example, pure cultures of lactobacilli, which are found in yogurt and other fermented milk products, helps restore an adequate balance of microbial populations during intestinal infections.

Innate immunity

If the microorganism successfully penetrates all barriers, it encounters the cells and mechanisms of the innate immune system. Innate immune defense is nonspecific in nature; in other words, its components identify and respond to foreign bodies, regardless of their characteristics. This system does not provide long-term resistance to specific infections. The innate immune system is the body's main defense tool in both humans and most living multicellular organisms.

Inflammation is one of the primary responses of the immune system to infection. Symptoms of inflammation usually include redness and swelling, which is an indication of increased blood flow to the affected tissues. Eicosanoids and cytokines, which are released by damaged or infected cells, play an important role in the development of inflammatory reactions. The former include prostaglanids, which cause an increase in temperature and dilation of blood vessels, as well as leukotrienes, which attract certain types of white blood cells. The most common cytokines include interleukins, which are responsible for the interaction between leukocytes, chemokines that trigger chemotaxis, as well as interferons, which have antiviral properties, namely the ability to inhibit protein synthesis in microbial cells. In addition, secreted growth factors and cytotoxic factors also play a role in the reaction to a foreign pathogen. These cytokines and other bioorganic compounds lead immune system cells to the site of infection and promote healing of damaged tissue by eliminating pathogens.

Acquired immunity

The acquired immune system developed during the evolution of the simplest vertebrate organisms. It guarantees a more intense immune response, as well as immunological memory, thanks to which each foreign microorganism is “remembered” by antigens unique to it. The acquired immune system is antigen-specific and requires the recognition of specific foreign antigens in a process called antigen presentation. This specificity of the antigen makes it possible to carry out reactions that are characteristic of specific microorganisms or cells infected by them. The ability to implement such reactions is supported in the body by “memory cells”. If the human body is infected by a foreign microorganism more than once, these specific memory cells are used to intensively eliminate this kind of consequences.

Cells of the immune system, whose functions are to implement the mechanisms of the acquired immune system, belong to lymphocytes, which in turn are a subtype of leukocytes. The overwhelming number of lymphocytes are responsible for specific acquired immunity, as they are able to identify infectious agents both inside and outside cells - in tissues or in the blood. The main types of lymphocytes are B cells and T cells, which are derived from pluripotent hematopoietic stem cells. In an adult, they are formed in the bone marrow, and T-lymphocytes additionally undergo separate differentiation procedures in the thymus. B cells are responsible for the humoral component of acquired immunity, in other words, they produce antibodies, while T cells are the basis of the cellular component of the specific immune response.

Conclusion

The human immune system is primarily designed to protect the body from the infectious effects of foreign bodies, objects and substances. It protects the body from the occurrence and development of diseases, identifies and destroys tumor cells, recognizes and neutralizes various viruses in the early stages and more. The immune system has at its disposal a large number of tools for quickly detecting and no less quickly eliminating harmful infectious agents. Also, do not forget that there is a method of developing immunity to a number of infectious diseases, such as vaccination. In general, the immune system is a guardian that protects and protects your health at all costs.

Partnership material with SANTO

No. 1. What is immunity?

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.

No. 2. What organs are part of the immune system?

  • Red bone marrow, spleen and thymus (or thymus) are the central organs of the immune system.
  • Lymph nodes and lymphoid tissue in other organs (eg, tonsils, appendix) are peripheral organs of the immune system.

Tonsils and appendix - organs necessary for the immune system. The main task of the human immune system is to produce protective cells.

No. 4. Types of immunity

  • Cellular immunity is represented by cells: T-killer cells, T-helper cells, macrophages, neutrophils, and so on.
  • Humoral immunity is represented by antibodies and their source - B-lymphocytes.

This gradation is very important, since many drugs act on either one or the other type of immunity.

There is another gradation - according to 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.

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.

No. 5. For example

To make it clearer, here’s an example: common juvenile warts (actually human papillomavirus type 3).

  • 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 is integrated 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.
  • 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, on the activity of all its links. After all, if, for example, at least one link falls out over a certain period of time, then the entire chain collapses, and the virus multiplies unhindered, penetrating into more and more new cells, contributing to the appearance of new ugly warts.

No. 6. Good and bad immunity

Science does not yet know how certain autoimmune processes are triggered in the body. For example, when a person’s immune system, out of the blue, begins to perceive its own cells as foreign and begins to fight them.

  • Good immunity is a state of complete immunity to various foreign agents. Outwardly, this is manifested by the absence of infectious diseases and good human health. Internally, this is manifested by the full functionality of all parts of the cellular and humoral components.
  • Poor (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, and it must be treated by eliminating all possible causes.

No. 7. Does immunity depend on lifestyle?

An interesting fact: the connection between lifestyle and the body’s ability to resist disease has not been proven to date. However, experts believe that healthy lifestyle strategies most likely have a positive effect on immunity. For the first time in a million, let’s repeat the rules that make sense to follow:

  • Quit smoking
  • Eat a balanced diet rich in fruits and vegetables, with a predominance of whole grains over flour products, and low in saturated fat.
  • Get rid of excess weight.
  • Limit your alcohol intake.
  • Finally, start getting enough sleep.
  • Avoid causing infections: wash your hands, wash your fruits and vegetables, and cook your meat thoroughly.
  • Keep your blood pressure under control and get regular checkups recommended for your age group or risk group for the disease (if you are included in one of them).

No. 8. Do vitamins and dietary supplements help the immune system?

If you eat normally, move a lot and get enough sleep, your body does not need vitamins and minerals. But if you are on a strict diet or your stomach and intestines do not absorb nutrients well, you need to take them in medicinal form. Here are a few nutrients to consider as dietary supplements:

  • Vitamin A. Vitamin A deficiency in the body has been proven to be associated with reduced immune system function and an increased risk of infections.
  • Vitamin B6. Vitamin B6 deficiency reduces the ability of lymphocytes to differentiate into T cells and B cells. Moderate doses of the vitamin help restore this ability.
  • Vitamin D. Its role in the functioning of the immune system is undeniable. Vitamin D, produced in the body under the influence of sunlight, has long been known as an important factor in the fight against tuberculosis, in the prevention of cancer, multiple sclerosis, and seasonal flu. Experts recommend taking a vitamin D3 supplement (not D2 - this form is poorly absorbed). Fish oil, which contains, in addition to D, vitamin A and healthy Omega-3 fatty acids, is also useful.
  • Zinc. This trace element is necessary for the normal functioning of T cells and other immune cells. The recommended daily dose of zinc is 15-25 mg, but no more. High doses have the opposite effect.

No. 9. Does stress affect the body's resistance?

No experiments have been conducted in this area - doctors believe that this is not ethical. Therefore, scientists have to be content with experiments on animals and some observations of the human world.

Thus, experimental mice infected with the herpes virus showed a decrease in T-cell activity under stress conditions. Reduced lymphocyte production was demonstrated by Indian macaque infants separated from their mother.

Scientists observed a decrease in T-cell activity in depressed patients, as well as in divorced men compared to married men.

A decrease in a number of immune indicators was demonstrated by residents of Florida who lost their housing after Hurricane Andrew, as well as hospital workers in Los Angeles after the earthquake.

Summary: it has been proven that stress weakens immunity. But it has not been proven that stressed people get sick more often than happy people.

No. 10. Do low temperatures lower immunity?

If you go for a walk in winter and are slightly cold, your immunity is unlikely to decrease. Today, science believes that colds, paradoxical as it may sound, are not associated with catching a cold.

To prove this hypothesis, scientists immersed volunteers in cold water, exposed them to temperatures close to 0°C, and studied the inhabitants of research stations in Antarctica and the northern regions of Canada. The results were mixed.

On the one hand, Canadian researchers noticed an increase in the incidence of respiratory infections in skiers during long-term training in the cold. At the same time, it is unclear whether this was the result of low temperatures or other factors (great physical activity, dry air).

So dress comfortably, beware of hypothermia and frostbite, and don’t worry about your immunity: most likely it will not suffer from the cold.

No. 11. Bonus: Echinacea, Garlic, and Lemon Don't Help Your Immune System

The most common recommendation at the first sign of a cold or flu is to take a high dose of vitamin C. However, science has not proven that vitamin C helps our immunity in any way. Same thing with echinacea: it has not been shown to be beneficial in studies. There is no convincing data on the effectiveness of garlic. However, garlic has been proven to fight bacterial, viral and fungal infections in vitro. It is possible that garlic is not useless for colds, although it does not seem to act through the immune system.

Immune system unites organs and tissues whose function is to protect the body from genetically foreign substances coming from the outside or formed in the body itself. The organs of the immune system produce immunocompetent cells (lymphocytes, plasma cells), biologically active substances (antibodies) that recognize and destroy cells and other foreign substances (antigens) that have entered the body or formed in it.

The immune system includes all organs that are built from lymphoid tissue and carry out protective reactions in the body, create immunity-immunity to foreign antigenic substances.

The organs of the immune system include red bone marrow, thymus, tonsils, appendix, lymph nodes, spleen, accumulation of lymphoid tissue (lymphoid nodules) in the walls of the hollow internal organs of the digestive, respiratory systems and genitourinary apparatus (Fig. 360).

The bone marrow and thymus are the central organs of the immune system, where lymphocytes are formed from bone marrow stem cells. In the bone marrow, B lymphocytes are formed from its stem cells. In the thymus, differentiation of T-lymphocytes (thymus-dependent) occurs. B-lymphocytes and T-lymphocytes from the bone marrow and from the thymus through the bloodstream enter the peripheral organs of the immune system, which include tonsils, lymphoid (Peyr's) patches, appendix, single lymphoid nodules, lymph nodes and spleen.

Central authorities immune systems are located in the human body in well-protected places (bone marrow - in the bone marrow cavities, thymus - in the chest cavity, behind the manubrium of the sternum). Peripheral organs immune systems are located in places of possible penetration of foreign substances into the body or along the paths of their movement in the body itself. The tonsils are located in the walls of the initial section of the digestive tube and respiratory tract, on the border between the oral cavity, nose and the cavity of the pharynx and larynx. Lymphoid (Peyre's) plaques are located in the walls of the small intestine (mainly the ileum), the appendix is ​​near the cecum, with a particularly abundant microflora.

In the mucous membrane of the digestive, respiratory and urinary tract organs there are numerous single lymphoid nodules that perform immune surveillance functions at the border of the body and the external environment (inhaled air, contents of the digestive tract). Lymph nodes, which are biological filters, lie on the paths of lymph flow (tissue fluid) from organs and tissues into the venous system. Particles of dead cells and coarse proteins, together with tissue fluid, enter the lymphatic channel, are retained and neutralized in the lymph nodes. The spleen, whose function is the immune control of blood, is located on the path of its flow from the arterial system to the portal vein.

Diffuse lymphoid tissue, represented by individual scattered cells of the lymphoid series, in some places forming not very dense cell clusters, is present in those organs where the antigenic danger is not very great. In places of constant antigenic potential

Rice. 360.Diagram of the location of the central and peripheral organs of the immune system in the human body.

1 - red bone marrow, 2 - thymus, 3 - lingual tonsil, 4 - palatine tonsil, 5 - tubal tonsil, 6 - pharyngeal tonsil, 7 - lymphoid nodules in the walls of the trachea and bronchi, 8 - lymph nodes (axillary), 9 - spleen, 10 - lymphoid nodules of the appendix, 11 - lymphoid nodules in the walls of the colon.

actions (tonsils, mucous membrane of the stomach, intestines, lymph nodes, spleen), lymphocytes form dense clusters measuring 0.5-1 mm, called lymphoid nodules, with reproduction centers (germentative centers).

Bone marrow(medulla ossium) is a hematopoietic organ and the central organ of the immune system. There is red bone marrow, which in an adult is located in the cells of the spongy substance of flat and short bones, the epiphyses of long (tubular) bones, and yellow bone marrow, which fills the bone marrow cavities of the diaphyses of long (tubular) bones. Red bone marrow contains hematopoietic stem cells - the precursors of all blood cells and the immune system (lymphocytes).

Thymus

Thymus(thymus), which was formerly called the thymus gland, is the central organ of immunogenesis. In the thymus, from stem cells coming here from the bone marrow with the blood flow, T-lymphocytes are formed, which leave the thymus with the blood flow and populate the thymus-dependent zones of the peripheral organs of immunogenesis. The thymus also secretes substances that affect the functions of T-lymphocytes.

The thymus consists of two asymmetrical right and left lobes, which are fused to each other at the level of their middle.

The thymus has a thin connective tissue capsule. The thymic parenchyma consists of darker cortex(cortex thymi) and lighter medulla(medulla thymi), occupying the central part of the thymus lobules. In the loops of the network formed by reticular fibers and cells, there are thymic lymphocytes(thymocytes), which lie more densely in the cortex than in the medulla, and stellate-shaped multi-processed epithelial cells - epithelioreticulocytes. The medulla also contains thymic corpuscles(corpuscula thymici), Hassal's bodies, formed by concentrically lying, highly flattened epithelial cells.

Innervation of the thymus: branches of the right and left vagus nerves, as well as branches of the cervicothoracic (stellate) and superior thoracic nodes of the sympathetic trunk.

Blood supply:branches of the internal mammary artery. Vienna The thymus drains into the brachiocephalic and internal mammary veins.

Tonsils

Tonsils:lingual and pharyngeal (unpaired), palatine and tubal (paired) - located in the area of ​​the root of the tongue, pharynx and nasal pharynx, respectively. They are diffuse accumulations of lymphoid tissue containing small, denser cellular masses - lymphoid nodules.

Lingual tonsil (tonsilla lingualis) unpaired, located under the multilayered epithelium of the mucous membrane of the tongue root, often in the form of two accumulations of lymphoid tissue.

The surface of the tongue above the tonsil is lumpy, between the tubercles there are openings of the mucous glands located in the thickness of the root of the tongue.

The lingual tonsil reaches its largest size by the age of 14-20; its length is 18-25 mm and its width is 18-25 mm. The lingual tonsil does not have a capsule.

The lingual tonsil consists of lymphoid nodules, the number of which (80-90) is greatest in childhood, adolescence and young adulthood.

Innervation of the lingual tonsil: branches of the glossopharyngeal and vagus nerves, as well as sympathetic fibers of the external carotid plexus.

Blood supply:branches of the right and left lingual arteries. Venous blood drains into the lingual vein.

Pharyngeal tonsil (tonsilla pharyngealis), unpaired, is located in the vault of the pharynx, where diffuse lymphoid tissue and lymphoid nodules are located, mainly with reproductive centers.

Innervation:branches of the facial, glossopharyngeal, vagus nerves and sympathetic periarterial plexuses.

Blood supply:branches of the ascending pharyngeal arteries. Venous blood

Palatine tonsil (tonsilla palatina) steam room, located in the tonsillar fossa between the palatoglossal and velopharyngeal arches. The medial (free) surface of the tonsil faces the pharynx. On this surface there are almond dimples into which almond crypts open. In the thickness of the tonsil, along its crypts, there are lymphoid nodules, mainly with reproduction centers. Around the lymphoid nodules there is diffuse lymphoid tissue (Fig. 361).

Innervation:branches of the greater palatine nerve (from the pterygopalatine ganglion), the tonsil branch of the glossopharyngeal nerve and sympathetic fibers from the internal carotid plexus.

Blood supply:branches of the lingual, ascending pharyngeal and descending palatine arteries. Venous blood flows into the veins of the pterygoid plexus.

Tubal tonsil (tonsilla tubaria) steam room, located in the area of ​​the tubal ridge, near the pharyngeal opening of the auditory tube. The tonsil consists of diffuse lymphoid tissue and a few lymphoid nodules.

Innervation:branches of the facial, glossopharyngeal and vagus nerves and periarterial sympathetic plexuses.

Blood supply:branches of the ascending pharyngeal artery. Venous blood flows into the veins of the pharyngeal plexus.

Appendix

Appendix (appendix, appendix vermiformis) extends from the lower part of the cecum, has numerous lymphoid nodules in its walls and internodular lymphoid tissue between them. The number of lymphoid nodules in the walls of the appendix in children and adolescents reaches 800, the nodules are located one above the other in 2-3 rows.

Innervation:fibers of the vagus nerves and the celiac (sympathetic) plexus.

Rice. 361.Microscopic structure of the palatine tonsil.

1 - crypts of the tonsil, 2 - integumentary epithelium, 3 - lymphoid nodules of the tonsil.

Blood supply:cecum branches of the ileocolic artery. Venous blood flows into the vein of the same name.

Lymphoid plaques of the small intestine

Lymphoid plaques (noduli lymphoidei aggregati), or group lymphoid nodules (Peyer's patches) are a cluster of lymphoid nodules located in the walls of the small intestine, mainly in its final section (Fig. 362). Lymphoid plaques look like oval or round formations, slightly protruding into the intestinal lumen. One plaque has from 5 to 150 or more lymphoid nodules, between which diffuse lymphoid tissue is located.

Single lymphoid nodules

Single lymphoid nodules (noduli lymphoidei solitarii) are present in the mucous membrane and submucosa of all tubular organs of the digestive, respiratory systems and genitourinary apparatus. Lymphoid nodules are located at different distances from each other and at different depths. Often the nodules lie so close to the epithelial cover that the mucous

Rice. 362.Group and single lymphoid nodules in the wall of the small intestine.

1 - serous membrane, 2 - muscular membrane, 3 - mucous membrane, 4 - mesentery of the small intestine, 5 - single lymphoid nodules, 6 - group lymphoid nodule (Peyer's patch), 7 - circular folds of the mucous membrane.

The melted shell rises above them in the form of small mounds. In the small intestine in childhood, the number of nodules varies from 1200 to 11000, in the large intestine - from 2000 to 9000, in the walls of the trachea - from 100 to 180, in the bladder - from 80 to 530. Diffuse lymphoid tissue is also present in the mucous membrane of all organs of the digestive, respiratory systems and genitourinary apparatus.

Innervationlymphoid nodules and lymphoid plaques are carried out along the branches of the vagus nerves and the celiac plexus.

Blood supply:peri-nodular hemocapillary networks formed by branches of organ arteries. Venous blood flows into the veins of the same name.

Spleen

Spleen(lien, splen), which carries out immune control of the blood, is located in the left hypochondrium, at the level of 9-11 ribs. The spleen has diaphragmatic and visceral surfaces. Diaphragmatic surface(facies diaphragmatica) facing the diaphragm. Anteromedial (visceral) surface(facies visceralis) contains the gate of the spleen, through which the artery and nerves enter the organ and the vein exits.

The spleen is covered on all sides by peritoneum, under which there is a thin fibrous membrane. Connective tissue trabeculae extend from the fibrous membrane into the organ, between which there is parenchyma, or pulp (pulp), spleen(pulpa splenica). Highlight red pulp(pulpa rubra), located between the venous vessels - the sinuses of the spleen, consisting of loops of reticular tissue filled with erythrocytes, leukocytes, lymphocytes, macrophages, and white pulp(pulpa alba), formed by periarterial lymphoid couplings, lymphoid nodules and macrophage-lymphoid couplings (ellipsoids), consisting of lymphocytes and other cells of lymphoid tissue (Fig. 363).

Periarterial lymphoid couplings in the form of several layers of lymphoid cells surround the pulp arteries along their entire length. Lymphoid nodules form in the thickness of the periarterial lymphoid couplings. Around the arterioles and capillaries there are 2-3 layers of cells of the lymphoid series - macrophage-lymphoid couplings (ellipsoids), which have a spindle shape.

Innervation of the spleen: sympathetic fibers from the celiac plexus and branches of the vagus nerves.

Blood supply:splenic artery. Venous blood flows through the splenic vein.

Lymph nodes

Lymph nodes (nodi lymphatici) are located on the paths of lymph flow from organs and tissues to the lymphatic ducts and lymphatic trunks flowing into large veins in the lower parts of the neck. Lymph nodes are biological filters for tissue fluid and the particles of cells contained in it that have died as a result of cellular renewal, and other foreign substances of endogenous and exogenous origin. Lymph flowing through the sinuses of the lymph nodes is filtered through loops of reticular tissue. The lymph receives lymphocytes formed in the lymphoid tissue of these lymph nodes. Lymph nodes are usually located in groups. Groups of lymph nodes are named by the area of ​​their location: (inguinal, lumbar, etc.) or by the name of the blood vessel next to which they are located (celiac, iliac lymph nodes). Lymph nodes adjacent to the walls of cavities are called parietal, parietal lymph nodes(nodi lymphatici parietales), located near the internal organs - visceral lymph nodes(nodi lymphatici

Rice. 363.Diagram of the location of white pulp in the parenchyma of the spleen.

1 - fibrous membrane, 2 - trabecula of the spleen, 3 - venous sinuses, 4 - ellipsoid arteriole (ellipsoid), 5 - brush arterioles, 6 - central artery, 7 - lymphoid nodule, 8 - lymphoid periarterial coupling, 9 - red pulp , 10 - pulp artery, 11 - splenic vein, 12 - splenic artery, 13 - trabecular artery and vein.

viscerales). There are superficial and deep lymph nodes. The shape of the lymph nodes is very different.

On the outside, the lymph node is covered with a connective tissue capsule, from which capsular trabeculae extend into the organ. At the point where the lymphatic vessels exit the lymph node, there is a slight depression - gates(hilus), in the area of ​​which the capsule thickens, forms a portal (hilar) thickening (Fig. 364). The portal (hilar) trabeculae extend from the portal thickening into the node. Through the gate, an artery, nerves enter the lymph node, veins and efferent lymphatic vessels exit. Between the trabeculae of the lymph node there are reticular fibers that form a network in the loops of which lymphoid tissue is located. The parenchyma of the lymph node is divided into cortex and medulla. Cortex(cortex) darker, occupies the peripheral parts of the node. Lighter medulla(medulla) lies closer to the gate of the lymph node. The cortex contains lymphoid nodules with and without a reproductive center. Around the lymphoid nodules there is diffuse lymphoid tissue, in which an internodular zone is distinguished - the cortical plateau. Inward from the lymphoid nodules, at the border with the medulla, there is a strip of lymphoid tissue called pericortical

Rice. 364.Microscopic structure of the lymph node.

1 - capsule, 2 - trabecula, 3 - afferent lymphatic vessel, 4 - subcapsular lymphatic sinus, 5 - cortical substance, 6 - poracortical (thymus-dependent) zone, 7 - lymphoid nodule, 8 - proliferation center of the lymphoid nodule, 9 - cortical lymphatic sinus , 10 - pulpal cords, 11 - cerebral sinuses, 12 - portal sinuses, 13 - efferent lymphatic vessel, 14 - portal thickening, 15 - blood vessels.

(paracortical) substance (paracortex), where there are mainly T-lymphocytes, as well as post-capillary venules. Through the walls of the venules, lymphocytes migrate into the bloodstream from the parenchyma of the lymph node and back. The medulla is formed by strands of lymphoid tissue - pulpy cords(chordae medullares), going from the cortex to the gate of the lymph node. Together with the lymphoid nodules, the pulp cords form the B-dependent zone.

lymphatic sinuses (sinus marginalis) to portal sinus(sinus hilaris). Along the capsular trabeculae lie cortical sinuses(sinus corticalis), along the pulpy cords are the sinuses of the medulla (sinus medullaris), which reach the gates of the lymphatic channel. Near the portal thickening, the sinuses of the medulla flow into the portal sinus located here. In the sinuses there is a fine-mesh network formed by reticular fibers and cells.

The parenchyma of the lymph node is penetrated by a dense network of narrow slits - lymphatic sinuses(sinus lymphaticus), through which the lymph entering the node flows from subcapsular (marginal) sinus(sinus marginalis) to portal sinus(sinus hilaris). Along the capsular trabeculae lie

cortical sinuses (sinus corticalis), along the pulpy cords - medullary sinuses(sinus medullaris), which reach the gates of the lymphatic bed. Near the portal thickening, the sinuses of the medulla flow into the portal sinus located here. In the sinuses there is a fine-mesh network formed by reticular fibers and cells.

Lymphatic system

Lymph nodes, lymphatic capillaries and vessels, ducts and trunks through which lymph flows are united under the general name - lymphatic system(systema lymphaticum) (Fig. 365).

Lymphatic capillaries (vasa lymphocapillaria) are the initial link of the lymphatic system. Tissue fluid, together with the substances it contains (large protein molecules, particles of dead cells, tumor cells), including foreign particles, is absorbed into the lumen of the lymphatic capillaries and is called lymph(lymph). Lymphatic capillaries are present in all organs and tissues of the human body, except for the brain and spinal cord, eyeball, inner ear, epithelial skin and mucous membranes, cartilage, spleen parenchyma, bone marrow and placenta. The diameter of lymphatic capillaries varies from 10 to 200 microns. When connected to each other, capillaries form in organs and tissues closed lymphocapillary networks(rete lymphocapillaria). The walls of lymphatic capillaries are built from a single layer of endothelial cells.

Lymphatic vessels (vasa lymphatica) are formed by the fusion of lymphatic capillaries. The walls of the lymphatic vessels are thicker, they consist of three layers (inner shell- tunica intima, middle shell- tunica media and outer shell- tunica externa). Lymphatic vessels have valves, the presence of which gives these vessels a characteristic bead-shaped appearance. The valves of the lymphatic vessels, formed by the folds of the inner membrane, allow lymph to pass in one direction - from the place of its formation in the capillaries towards the lymph nodes. From the lymph nodes, through their efferent lymphatic vessels, lymph flows either to the next (along the lymph flow) lymph nodes, or to the collector vessels - lymphatic trunks and lymphatic ducts, which flow into the venous angle formed on the right and left at the connection of the internal jugular and subclavian veins of the corresponding sides

Rice. 365.Human lymphatic system. Front view.

1 - lymphatic vessels of the face, 2 - submandibular lymph nodes, 3 - mental lymph nodes, 4 - mouth of the thoracic duct, 5 - anterior mediastinal lymph nodes, 6 - axillary lymph nodes, 7 - superficial ulnar lymph node, 8 - superficial lymphatic vessels of the forearm , 9 - lumbar lymph nodes, 10 - subaortic lymph node, 11 - common iliac lymph nodes, 12 - superficial inguinal lymph nodes, 13 - medial group of superficial lymphatic vessels of the leg, 14 - lateral group of superficial lymphatic vessels of the leg, 15 - superficial lymphatic vessels feet, 16 - deep lymphatic vessels of the foot, 17 - deep lymphatic vessels of the leg, 18 - deep lymphatic vessels of the thigh, 19 - deep lymphatic vessels of the palm, 20 - deep inguinal lymph nodes, 21 - external and internal iliac lymph nodes, 22 - deep lymphatics vessels of the forearm, 23 - thoracic duct, 24 - deep ulnar lymph node, 25 - intercostal lymph nodes, 26 - subclavian trunk, 27 - jugular trunk, 28 - deep cervical lymph nodes, 29 - jugular-digastric lymph node, 30 - mastoid lymph nodes nodes, 31 - preauricular lymph nodes.

Lymphatic trunks (trunci lymphatici) and lymphatic ducts(ductus lymphatici) are large lymphatic vessels that collect lymph (tissue fluid) from large parts of the body. There are six large lymphatic ducts and trunks in the human body. The thoracic duct, left jugular and left subclavian trunks flow into the left venous angle) into the right venous angle - the right lymphatic duct, right jugular and right subclavian trunks.

IN right subclavian trunk(truncus subclavius ​​dexter) lymph flows from the right upper limb, into right jugular trunk(truncus jugularis dexter) - from the right half of the head and neck. IN right lymphatic duct(ductus lymphaticus dexter) the right bronchomediastinal trunk flows into, collecting lymph from the organs of the right half of the thoracic cavity.

Left subclavian trunk (truncus subclavius ​​sinister) collects lymph from the left upper limb, left jugular trunk(truncus jugularis sinister) - from the left half of the head and neck. The largest lymphatic vessel, which also flows into the left venous angle, is thoracic duct(ductus thoracicus), through which lymph flows from the lower extremities, walls and organs of the pelvis and abdominal cavity, as well as the left half of the chest cavity.

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 a microorganism, abnormal cell, or other pathogen that causes a 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:

  1. 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. A distinctive feature of this type of immunity is 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;
  2. Nonspecific (innate) immunity– a protective function that begins to work from the moment of birth. This system goes through the formation stage simultaneously with the intrauterine development of the 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 to human health by nature.

The main characteristic of 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

Conventionally, the entire complex of 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. Probiotics will help enhance the effect of taking fermented milk products.

Proper nutrition is the key to strong immunity

Fortification

Regular consumption of foods with a high content of vitamins C, A, E will provide you with the opportunity to provide yourself with 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 appropriate vitamin complex at 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,