The human lymphatic system (HLS) is a component of the vascular system, which is important in cleansing the tissues and cells of the body. Lymph nodes are links in the LChS, each of which is responsible for filtering a clear liquid (lymph) from harmful substances.

It is impossible to say unequivocally why the lymphatic system is needed, since it has numerous functions, which will be discussed below.

The structure of the LSC includes:

• lymph;
• lymphatic vessels and capillaries;
• lymph nodes (immune links, formations).

The circulatory and lymphatic systems differ significantly from each other. There are no erythrocytes in a clear liquid, and there are much fewer protein molecules than in blood. LSP is not closed. It lacks the main pump, i.e. the heart. Lymph moves into the LSP smoothly and under minimal pressure.

The structure of the human lymphatic system will tell the scheme. It will also indicate the features of the movement of the lymph. The components of the most important part of the body are described in detail below.

Lymph

The word "lymph" in Latin means "clear water". This is not surprising, because this liquid cleanses the body of harmful substances. In its structure, lymph is a connective tissue and has many lymphocytes, practically does not contain platelets and erythrocytes.

The composition of "pure water" includes the products of the vital activity of the body, including large molecules of proteins. Most often they are viruses that are filtered by the lymphatic system. The clear fluid contains various hormones produced by the endocrine glands.

Lymph moves from the periphery to the center, moving from bottom to top. It passes from small capillaries, which gradually flow into large vessels. The movement goes through formations - lymph nodes that perform the function of filtering. In total, the lymphatic system contains about 500 such anatomical structures.

Lymphatic vessels and capillaries

Click to enlarge

LSP outwardly resembles the roots of a tree. This brings it closer to the nervous and circulatory systems. Lymphatic vessels permeate almost the entire human body, excluding the sclera, the inner part of the ear, and some other segments.

From the tissues, lymph enters the capillaries, which are connected to the lymphatic vessels. The latter surround all organs and often lie in several layers.

The lymph passes through the vessels to the regional links of immunity, localized in the inguinal and elbow areas, armpits, chest, etc. Large trunks emerge from the nodes, which flow into the ducts that open the way to the circulatory system for “clean water”.

Lymph nodes (immune links)

A lymph node (LN) is often a rounded formation that has a gray-pink color and sizes from 0.5 to 50 mm or more. Immune links are localized along the lymphatic and near the blood vessels. Each of the formations serves as a kind of filter. They are responsible for cleansing the body not only from microbes, but also from cancer cells. Thus, it is an essential part of human health.

The node structure includes:

• connective tissue capsule;
• stroma (structural basis) in which macrophages are located;
• cortical substance, consisting of a superficial part and a deep cortex.

The immune links are based on lymphoid tissue, in which there are lymphocytes, reticulocytes and plasma cells. In the formations, the most important components of immunity develop - B-lymphocytes, which participate in its formation.

Functions of the lymphatic system

Lymphocytes actively fight bacteria and viruses that enter the body from outside. This ensures the normal functioning of the body's defenses. Immune links increase if the number of microbes is too large and they can not cope with them. In this case, the help of a specialist is required.

The lymphatic system performs the function of cleansing from microbes and is responsible for the delivery of the most important elements to the venous bed. Later, these components through the blood circulation enter the cardiovascular system and leave the human body.

Most harmful substances are eliminated even at the stage of filtration with a clear liquid, i.e., they are destroyed in the links of immunity. The body normally “works” thanks to the lymphatic capillaries, through which proteins and other compounds come from the interstitial space into the clear liquid.

The way "clear water" flows is determined by the degree of muscle tension. Physical activity has a beneficial effect on the movement of lymph, promotes high-quality cleansing of the body and normalization of human health.

Major diseases

The most common problems with the lymphatic system are:

1. Lymphoma:

• Hodgkin - LSP cancer with a high degree of malignancy;
• non-Hodgkin's (B-cell or T-cell).

1. Lymphadenitis - inflammation of the immune links:

• acute, provoked by viruses or bacteria;
• chronic, caused by syphilis, immunodeficiency or tuberculosis, less often - influenza;
• purulent (occurs in advanced cases, characterized by the formation of exudate in the node).

1. Lymphedema (including elephantiasis) is a persistent swelling of an extremity that develops as a result of damage to the LSP, which contributes to impaired lymph circulation or the formation of lymphostasis.

Signs of malfunction of the lymphatic system are:

• swelling of the fingers;
• pain in the chest;
• cold extremities;
• cellulite;
• dry skin.

The lymphatic system and lymph are the most important components of the body, for the normal functioning of which are useful:

• physical activity;
• trampolining;
• yoga classes;
• proper diet;
• breathing exercises;
• rejection of bad habits;
• food according to Ayurveda.

If the cleansing function is violated, health problems arise. A person needs continuous work of LSP. How the structures cope with their task depends on his well-being. To maintain health, lymph is needed periodically.

Which doctor should I contact?

Treatment of LSP pathologies is reduced to the use of drugs or surgery. Having found deviations from the norm, you need to consult with a pediatrician / therapist who will refer you to a specialist.

Below is a table explaining which doctors deal with LSD diseases.

leading symptom	Narrow specialist
Enlarged lymph nodes in the neck	Otorhinolaryngologist
Soreness and proliferation of lymphoid tissue under the jaw	Dentist
Increase in immune links in the groin area	Gynecologist or urologist
Change in the size of formations, accompanied by hemoptysis, a sharp decrease in weight, increased sweating, fever

In our article today:

Introduction.

To maintain life, along with the supply of nutrients, energy resources and oxygen, it is also necessary to remove metabolites and toxic substances from tissues. It has been experimentally established that with complete starvation (only with the intake of water), a person and higher Animals can live for 10-20 days, while if the excretory system is disturbed, death occurs within the very first day.

In addition to the kidneys, the lungs, intestines, and sweat glands also perform an excretory function. In ancient Egypt, friends at a meeting instead of "how are you?" asked each other: "How do you sweat?". It is known that with profuse sweating, the body is freed from many toxins, and this is very important for health. Previously, it was believed that the excretion of metabolites and toxic substances from the body mainly refers to the function of the blood flowing through one or another excretory system.

It has now been established that the excretory and many other functions of the body are closely connected not only with blood, but also with lymph. Removal of toxic substances from the body in various ways is possible with the coordinated work of a single drainage system - the lymphatic venous bed. The scientific study of lymph is at least three hundred years old. However, intensive study of it began to be carried out relatively recently.

To date, it has been established that lymph circulation performs numerous important functions, and its violation leads to the development of severe complications and aggravates the course of many diseases. Today, opportunities have been found to influence the course and development of various pathological processes in the body through the lymphatic system. The impact on the lymphatic system has become widely used in immunology, oncology, cardiology, toxicology, and traumatology. There was even a new term - "lymphotherapy". Endolymphatic administration of various drugs is widely used in medical practice. In various pathological processes, endo- and exotoxins get into the lymph much faster than into the blood. The high efficiency of removing "poisoned lymph" from the body through the catheterized thoracic duct (for various types of intoxication, burns, liver and pancreas lesions, thrombosis, peritonitis, myocardial infarction, extreme and terminal conditions) has been proven both in the experiment and in the clinic.

One of the mysteries of the lymphatic system has been revealed - its role in the body's immune responses. There is an assumption that the lymphatic system is a morphological synonym for the immune system, and lymphocytes are its leading link. The presence of two independent, but jointly creating immunological reactions of T- and B-lymphocytes was discovered. Today, lymphology is developing rapidly. Stimulation of lymphatic drainage of tissues is assessed as one of the principles of pathogenetic therapy for a variety of (especially severe) diseases.

Lymph of a healthy person.

What is lymph?

It is believed that the aquatic environment is the basis of all processes occurring in the body, and maintaining its constancy is the basis of homeostasis. Speaking of a liquid medium, they usually mean blood, which is functionally associated with all tissues and cells of the body. It provides tissues and organs with oxygen, nutritious, plastic material, promotes the removal of toxic and unnecessary metabolic products from the body, performs neurohumoral function and thermoregulation.

The protein fraction of the blood is vital. Its gamma globulin fraction, for example, is necessary for the biosynthesis of antibodies and the enhancement of defense mechanisms. All deviations in the body are immediately reflected in the blood picture. Along with blood in our body, there are no less important liquid media - lymph, interstitial, cerebrospinal fluid and others - closely related to blood. The humoral direction founded by Hippocrates has been continuously changing over the course of twenty centuries of history, acquiring a modern form of the doctrine of humoral environments and humoral transport. It is generally accepted that the system of humoral transport, including the general blood circulation and movement in the "blood - tissue - lymph - blood" chain, is functionally one.

Lymph (in translation - pure water, moisture) is a transparent liquid of slightly yellowish color, sugary smell and salty taste. Some researchers call lymph only the fluid that is in the lumen of the lymphatic pathways (lymphatic capillaries, vessels and sinuses of the lymph nodes). Lymph is an interstitial fluid separated from the interstitium by an easily permeable layer of endothelium. It plays an essential role in maintaining the balance of tissue fluids.

Hence the concept of tissue lymph is born. Potential lymphoforming substrate - interstitial fluid. In the main substance, in the networks of collagen and elastic fibers, there are fixed and mobile elements of the interstitial tissue: pericytes, macrophages, fibrocytes (collagen producers), endotheliocytes, lymphocytes, etc. All of them are involved in certain processes that ensure the normal functioning of the microcirculation system, metabolism substances, the production of vasoactive amines, the mobility of the interstitial substance, the protective reactions of the body. The composition of lymph changes not only depending on the state of the body, but also on the functions of the organ from which it flows.

The amount of lymph in the body is not precisely defined. It is believed that in the lymphatic vessels of a person weighing 60 kg at rest, on an empty stomach contains 1200-1500 ml of lymph. It primarily consists of lymphocytes (there are up to 20,000 of them in the lymph of the thoracic duct in 1 mm3) - the main protective cells of the body. In humans, 35,546 billion lymphocytes enter the bloodstream through the thoracic duct per day.

In terms of chemical composition, lymphoplasm is close to blood plasma, but contains less protein. There are relatively more albumins in the lymph than in the blood plasma, since they, having a smaller molecule, diffuse faster into the lymphatic capillaries. The thoracic duct lymph contains fibrinogen and prothrombin; it coagulates more slowly than blood, forming a loose clot consisting of fibrin filaments and white blood cells. Lymph, like blood, contains all the formed elements, except for platelets and erythrocytes, which enter it under pathological conditions (shock, tumor growth, inflammation, etc.). In terms of mineral composition, lymph also resembles blood plasma. In the first place is sodium chloride (67% of the solid residue), which gives the lymph a salty taste. Sodium carbonate accounts for 25%. Calcium, magnesium, iron ions are also present in the lymph (in small quantities). The main lymph cations are sodium, potassium, calcium, magnesium, anions - chlorine, phosphorus and protein, which behaves like an anion in the alkaline environment of the lymph. In samples of peripheral lymph, many trace elements were found that are of great importance in the physiology and pathology of the body.

To date, the presence of a special lymphatic system has been established, which includes lymph nodes, follicles, tonsils, spleen, thymus (thymus gland). The main functioning element of the lymphatic system is the lymphocyte. In an adult, lymphocytes circulating in the blood account for about 30% of the total number of leukocytes (in children under 5 years old, about 50%). Mature (small) lymphocytes make up the bulk of lymphoid tissue and over 95% of lymph cells.

Particular attention should be paid to the role of the thymus. It was experimentally established that as a result of the removal of the thymus in a newborn animal, the lymphatic system did not develop. Such animals constantly suffered from intestinal disorders, inflammations, various infections, after a while they inevitably died. It turned out that the removal of the thymus led to the almost complete disappearance of lymphocytes from the blood - cells that play a leading role in the body's defense reactions.

In newborn animals, after a few weeks, this caused a complex of phenomena known as "wasting disease" (sharp aplasia of lymphoid tissue, cachexia, lethargy, diarrhea). If the thymus was transplanted into experimental animals, their immune system was restored.

The main morphological substrate of immunogenesis are lymphoid organs. In cases where the liver, kidneys, and skin show immunological activity, there are serious grounds to attribute this activity not to the specific perichyma of these organs, but to the lymphoid or undifferentiated mesenchymal cells that have penetrated into them. With the weakness of the thymus, inflammation of the lungs develops, the flu and other diseases are severe.

The thymus differs from other organs of the lymphatic system in a number of histological features. Lymphoid elements, of which the thymus mainly consists, are morphologically identical to peripheral blood lymphocytes, but differ from the latter in the nature of the response to physical, chemical, hormonal and immunological effects and to infection. The totality of lymphoid organs in the conditions of the whole organism functions as a single system. The unity of this system is ensured by two main factors: 1) general hormonal and, probably, neuroreflex regulation; 2) special functional connections between individual lymphoid organs.

There is a distinct specialization in the system of lymphoid organs. The first, and sometimes the only object of action of the antigen and, accordingly, the antibody-producing organ is the regional lymph nodes. It has been shown that with the introduction of antigens, the amount of antibodies increases in the regional lymph nodes, and at an earlier time, in a higher titer than in blood serum. Sometimes a similar function can be performed by accumulations of lymphoid tissue or undifferentiated mesenchymal cells directly at the site of invasion of the antigenic factor (in the intestines, lungs, etc.). If a significant dose of the antigen, without being delayed by the regional node, enters the blood, the spleen, distant lymph nodes, lymphoid elements of the bone marrow, etc., are also included in the process of antibody formation.

Cells of the lymphoid type are found in all vertebrates. However, only in higher vertebrates is the lymphoid tissue distinctly separated from the myeloid tissue. One can therefore think that a single lymphomyeloid hematopoiesis, observed in higher vertebrates in the embryonic period, is a kind of recapitulation. A new stage in the development of lymphoid tissue was due to the emergence and improvement of a special drainage system of the body - lymphatic vessels.

The reduced (compared to blood) content of leukocytes and antibodies in the lymph, the initial remoteness of the lymphatic vessels from the main accumulations of lymphoid tissue, the ease of spread of infectious agents throughout the body with the flow of lymph - all this required the appearance of lymph nodes. Their appearance contributed to the protection constancy of the internal environment of the body not only due to the inherent barrier function of the lymph nodes, but also due to the fact that now the body was able to develop means of specific immunological protection (antibodies, sensitized lymphocytes) in response to a local antigenic stimulus before the infectious agent enters the bloodstream.

The place of formation of lymph, the roots of the lymphatic system are the lymphatic capillaries, which, together with postcapillaries, lymphatic vessels, lymph nodes and the main collector trunks, serve as lymphatic pathways. Since the functions of the lymphatic vessels and the main collector lymphatic trunks are only to conduct lymph, and the lymph nodes perform barrier, protective, exchange and reservoir functions, the structure of these sections of the lymphatic pathways differs significantly from each other.

The lymphatic system proper begins with the lymphatic capillaries, which are closely related to the blood capillaries. Their diameter is several times larger than blood vessels and reaches 35 microns. The body has reserve capillaries that fill up with increased lymph formation. It has been established that there are no lymphatic capillaries and vessels in the brain and spinal cord, meninges, bones, eyeball, cornea, hyaline cartilage, epidermis, placenta. They are relatively few in muscles, dense connective tissue anatomical formations (ligaments, fascia, tendons). They are unevenly distributed in the glands. Lymphatic capillaries form dense networks in the subcutaneous tissue, in the walls of internal organs, serous membranes, joint capsules.

The architecture of networks of lymphatic capillaries and plexuses of lymphatic vessels corresponds to the design of organs and their functions, while the processes of lymph formation are determined primarily by the state of permeability of the walls of blood capillaries and lymphatic terminals, the mobility of the interstitial gel. Unlike blood vessels, movement in lymphatic capillaries is one-way.

Lymphatic capillaries, merging, pass into the lymphatic vessels. The larger the lymphatic vessel, the greater the distance from it are the capillaries and venules. And vice versa, blood capillaries adjoin almost closely to thin lymphatic vessels and postcapillaries. Depending on the structure of the middle membrane, the lymphatic vessels are divided into two groups: amuscular and muscular. Muscleless vessels are formed by a layer of endothelial cells, which is surrounded by a connective tissue sheath containing collagen and elastic fibers. Most human lymphatic vessels, especially in the lower half of the body, on the lower extremities, are muscular.

The structure of the lymphatic vessels, as we see, is not the same. This variability can be observed in the structure of even the same vessel in its various parts. The valve system assumes unidirectional lymph flow. However, in conditions of pathology, in the presence of an obstacle to the flow of lymph (blocking of transport routes, lymph nodes) due to overstretching of blood vessels and insufficiency of valves that are unable to hold the “column” of lymph, as well as due to a decrease in the contractile activity of the muscle layer of the vessel wall (it is impregnated with toxin transudate) the flow of lymph from an intact zone can cause its reverse flow with the opening of lymphovenous anastomoses or the formation of lymphatic collaterals.

Lymph nodes are located on the path of superficial and deep lymphatic vessels and through them they receive lymph from those tissues, organs or parts of the body in which the vessels originate. Such nodes are called regional, or regional. The lymphatic system of mammals is characterized by the presence of a large number of lymph nodes: in a dog, for example, there are an average of 60 nodes, and in humans - 460. Some authors consider the lymph node to be a key area of ​​the lymph flow. They contain smooth muscle elements and can contract under neurohumoral influences. There are afferent lymphatic vessels, through which the lymph enters the lymph nodes, and efferent, through which the lymph flows. The number of bearers exceeds the number of bearers. The lymph nodes and primary nodules lying on the paths of the lymph flow not only determine the nature of the lymphodynamics, but also leave a significant imprint on the cellular composition of the lymph. The circulation of fluid from the blood to the tissues, its movement in the tissues, the flow from the tissues into the blood and lymph are all links in a single system of humoral transport.

Particularly important here belongs to the PAF system (coagulation, anticoagulation, fibrinolysis) in the blood and lymph. By actively influencing the SAF, it is possible to control the movement of fluid from the blood to the tissues and from the tissues to the lymph, which can be important in medical practice.

What keeps lymph moving?

It was found that amphibians and reptiles have so-called lymphatic hearts - special contractile organs, the walls of which contain muscle elements. The frog has two pairs of "lymphatic hearts", and the tailed amphibians have 15 paired lateral "lymphatic hearts" and 8-10 "lymphatic hearts" in the scapular, pelvic and other areas. In birds, "lymphatic hearts" can be observed only at the stage of embryonic development, while in mammals there are no such hearts at all. The movement of lymph in them occurs due to the contraction of skeletal muscles, the suction capacity of the chest, the movement of large nearby arterial pulsating vessels, etc. Some authors argue that the lymph nodes of warm-blooded animals have taken over the function of the disappeared lymphatic hearts. But it is difficult to agree with this. It should be noted that more lymph flows to the node than flows out. Lymph nodes absorb lymph like a sponge, but not all of it is given away, part of the lymph lingers in the node. It is more correct to consider that in warm-blooded animals the lymph nodes are additional organs of lymphopoiesis, which have developed in connection with a more intensive metabolism. It is believed that the wall of the lymphatic vessel took over the function of the disappeared lymphatic hearts, since only in warm-blooded animals do the lymphatic vessels acquire a characteristic clear-shaped shape with well-developed muscle fibers in the walls and a valve apparatus peculiarly arranged to regulate the flow of lymph.

An extremely important discovery in the field of lymphodynamics was the discovery of the rhythmic pulsation of the thoracic duct in humans. As you can see, lymph circulation is an extremely complex process. The information available in the literature indicates the important role of electrolytes and a number of microelements in its work. For the contractile activity of the muscles of the lymphatic vessels, for example, calcium ions are needed. When they are removed, the mechanical activity of the smooth muscle cells of the lymphatic vessels immediately stops. Manganese ions have a depressing effect on the contraction of the lymphatic vessels. Lithium and cobalt salts (at doses higher than biotic) dilate the lymphatic capillaries, and salts of rubidium, selenium and partly copper (also at doses higher than biotic), enhancing the rhythmic contraction of the neuromuscular apparatus of the wall of the lymphatic vessels, accelerate the lymph flow.

Unlike the circulatory system, as already mentioned, the lymphatic system is characterized by a unidirectional current. This circumstance makes it possible to accurately determine its initial link - the "fixed reference point". Such an initial point should be considered lymphatic capillaries, since only their content fully corresponds to the term "lymph". In humans, the central collector of lymph is the thoracic duct. Numerous lymphatic vessels flow into it, collecting lymph from the lower extremities, pelvis, abdomen, left half of the chest, from the heart and left lung, from the left upper limb, from the left half of the head and neck. This main lymphatic collector is supplemented by the right lymphatic duct, which is formed from the confluent lymphatic vessels of the right half of the head, neck, chest and right upper limb. It flows into the right venous angle. In a biological sense, the lymphatic system is considered closed (closed), but communicating with the circulatory system at the confluence of the thoracic and right lymphatic ducts.

Main functions of the lymphatic system.

The primary task of the lymphatic system, as well as the circulatory system, is to provide all organs and tissues of the body with nutritious, energy and plastic materials and remove metabolites and toxic substances from there. The lymphatic system is not only a transport, but also a physiologically active link, it makes its own independent, far from unambiguous contribution to the composition and condition of the products carried through the vessels.

It plays a particularly important role concentration, barrier, immune functions, which may be affected by the PAF factors. The lymphatic system takes an active part in the metabolism of proteins, fats, vitamins, etc. The participation of lymph nodes in the processes of digestion and metabolism is obviously determined phylogenetically - throughout the evolution of vertebrates, the association of lymphatic tissue with the digestive canal can be traced.

Feeding animals on a diet rich in fat causes hypertrophy of all lymphatic tissues, especially the tonsils, lymph nodes and intestinal follicles. An increase in the number of free macrophages with trapped fat was noted. Fasting leads to a decrease in the number of lymphocytes, the fat content in the nodes decreases.

Lymph nodes are also involved in the metabolism of proteins and in the production of a number of blood proteins (including immunoglobulins). An increase in protein concentration was noted during the passage of lymph through the lymphatic vessels, especially at its low speed. Participation of lymphatic capillaries and postcapillaries in metabolism is predetermined by their orientation and location in vascular microstructures. They are located in the zones of maximum filtration of fluid and substances - in the region of the venular section of the capillary network and post-capillary segments of venules.

Of particular interest is the study of the endothelium of the lymphatic capillaries in a number of diseases, when metabolic processes and the permeability of vascular membranes are disturbed. In such cases, the outgoing protein impregnates the main substance of the connective tissue structures surrounding the capillaries. The main point that causes a number of pathological changes with increased capillary permeability is the blockade of active elements of the connective tissue that have gone beyond the vascular walls. Violation of the permeability of the walls of blood capillaries and other parts of the microvasculature entails disordered transport of fluids, blood cells pass into the tissues, and then into the lumen of the lymphatic capillaries.

Almost all lymphoid organs (with the exception of the thymus) are characterized by a barrier function - the ability to detain and, if possible, neutralize foreign particles and substances entering the organ. Due to the special structure of the lymphoid organs and the phagocytic activity of their cells, most lymphoid organs trap and neutralize bacteria that have entered the lymph. Especially great is the importance of the lymph nodes, which fix microorganisms even before they enter the bloodstream and are therefore a kind of "first line of defense" of the body. The barrier function of lymphoid organs, being a nonspecific factor of immunity, at the same time is a necessary prerequisite for the formation of a specific immunological reaction of this organ and the whole organism.

Other foreign substances are also absorbed in the lymph nodes. Some of them (mascara, thorium, oily products) linger in the lymph nodes forever. Even direct washing of nodes does not help. Numerous facts show that the lymph nodes play the role of not so much a mechanical as a biological filter. However, in cases where the cellular and humoral resources of a given organ and the whole organism as a whole are insufficient to neutralize the pathogenic factor, the barrier function turns into an unfavorable side: the lymphoid organ becomes a reservoir, a focus of real danger. Take for example chronic tonsillitis, foci of infection in the lymph nodes with tuberculosis, brucellosis, metastasis to regional nodes of tumor cells, etc.

The endothelium of the lymphatic capillaries is extremely sensitive to mechanical, chemical, temperature and other influences and reacts to them by a change in permeability. Endothelial cells are able to adsorb protein particles, lipids and other substances. This property of cells is very important, as it is aimed at ensuring the absorption of liquid with toxins dissolved in it, as well as the absorption of foreign particles, bacteria, and viruses.

In the tissue of the nodes, the formation of lymphocytes occurs. They enter the lymph flow, and then through the thoracic and right lymphatic ducts into the blood. The number of lymphocytes in the lymph flowing from the lymph node is greater than in the incoming one.

Lymph and the immune system of the body.

It has long been known that the protective function of the body largely depends on the lymphatic system. For the first time this question was developed by the outstanding Russian scientist I. I. Mechnikov. He explained immunity as a phenomenon of intracellular digestion of microbes and called this process phagocytosis. Subsequently, humoral factors of immunity were identified, which primarily include antibodies. The active participation of lymphoid organs was also established in the implementation of humoral factors of immunity. It has now been established that phagocytosis (the main non-specific factor) and antibodies (the main specific factors of immunity) act together and form the basis of immunological resistance.

The central figure of the immune system is the lymphocyte, and the substrate for the formation of specific immunological reactions is the lymphoid tissue. The totality of human lymphoid organs and tissues is the thymus gland (thymus), spleen, lymph nodes, group lymph follicles and other lymphoid accumulations, bone marrow and peripheral blood lymphocytes. The leading function of the lymphoid organs is maintaining the constancy of the internal environment of the body.

The bulk of lymphocytes is formed in the lymph nodes and lymph follicles of the digestive tract. In addition, they can be produced in the spleen, thymus, and bone marrow.

The nature and degree of participation of various lymphoid organs in immunological processes are not the same. Some lymphoid organs (lymph nodes, spleen) are the direct substrate of the immunogenesis process, others (the goiter, the bag of Fabricius) participate in them indirectly, regulating the immunoreactivity of the lymph nodes and spleen.

Lymphoid cells are capable of carrying out their immunological function autonomously, sometimes even against other cells of the organism in which they are located. At the same time, the level of their immunoreactivity is regulated by hormonal and, possibly, reflex mechanisms.

A number of studies have shown the ability of large lymphocytes and cells of the germinal centers of lymphoid tissue to produce antibodies, normal gamma globulins, and macroglobulins. The question of the ability of small lymphocytes to produce antibodies remains debatable. It is believed that the main precursors of cells that synthesize antibodies are immature cells of lymphoid tissue: hematocytoblasts and lymphoblasts (large lymphocytes). It is not clear, however, whether these cells are the object of action of the antigen or an intermediate link in the chain of cellular transformations. Large lymphocytes store immunological information (memory) about the previous antigenic stimulus for at least 600 cell generations.

Lymphoid organs after primary immunization acquire specifically increased reactivity to this antigen. The expression of this altered immunoreactivity is, firstly, the ability to respond to smaller doses of antigen and, secondly, a more rapid and vigorous formation of antibodies (revaccination effect). An increase in immunoreactivity as a result of previous exposure to an antigen is a major factor in delayed-type allergic reactions. The immunological memory of lymphoid cells is an essential factor in the body's anti-infective defense.

Recent works have shown a very important role of the thymus gland not only in immunity, but also in the formation of the lymphoid system. This gland is actually the first central lymphoid organ, where mainly T-lymphocytes mature. This type of lymphocytes constantly undergoes training in the thymus gland and learns the ability to separate "own" from "alien". After that, the killers ("killers") and helpers ("assistants"), respectively, perform their functions. In addition, the thymus releases into the blood hormone-like substances that promote the maturation of T-lymphocytes. It supplies lymphocytes to other lymphoid organs, especially in the early postembryonic period.

The thymus and spleen are a kind of peripheral lymph nodes that are actively involved in the neurohumoral regulation of the lymphatic system. Removal of the thymus in newborn animals causes persistent pathological changes, among which the leading factor is systemic hypoplasia of the lymphoid tissue.

The cells of the spleen, as well as the cells of the lymphoid nodes, are characterized by immunological memory - the ability to respond to repeated injection of the antigen with a faster and more intense production of antibodies. In the spleen, in addition to antibodies, lymphocytes or lymphocyte-like cells are also produced, which migrate to other organs, and there they turn into cells that produce antibodies.

The body's resistance to infections and other pathogenic factors depends not only on the ability to develop a highly specialized immune response, but also on numerous so-called non-specific protective reactions of the body. Such reactions include, for example, the impermeability of normal skin and mucous membranes for a variety of microorganisms and the presence of bactericidal substances in skin secretions, gastric juice, blood and other body fluids (saliva, tears, etc.). Specific and non-specific protective factors work together. The significance of the lymphatic system is far from being limited to what has been said. The development of the doctrine of lymph contributes to the identification of its new functions.

Factors affecting the lymph and lymph flow.

Conventionally, they can be divided into internal and external, natural and artificial.

Among the internal factors in the regulation of lymph flow, an important role belongs to the own activity of the lymphatic vessels. Internal factors are inherent in the lymphatic system itself. The concept of own, internal, forces of lymph flow includes lymph formation and contractile activity of lymphatic vessels and nodes. The strength of lymph formation is the initial volume of lymph, without which lymph flow is impossible.

In the transport of lymph, one should also take into account the viscosity of the lymph flowing from the periphery, which can change if lymph formation is disturbed, the tone of the lymphatic valves, the external pressure on the wall of the lymphatic vessel of muscle contractions of the organ and adjacent blood vessels, as well as the values ​​characterizing the mechanical properties of the wall of the lymphatic vessel - thickness and radius of lymphangions, elastic properties of its wall. The intensity of lymph formation correlates with the intensity of blood circulation.

It was previously believed that external factors (respiratory movements of the lungs, rhythmic changes in the volume of the intestines, spleen, pulsation of the walls of blood vessels and contractions of skeletal muscles) are decisive in the promotion of lymph. The proof of this was the almost complete cessation of lymph flow from the immobilized limb. Subsequently, the appearance of edema after prolonged immobilization of the limb (in the experiment) and, along with dilatation of the lymphatic vessels, dystrophic changes in their walls were established. This indicates a violation of the trophism of the lymphatic vessels. The noted changes in the lymphatic vessels did not appear immediately, but after several weeks and even months. It has been noted, however, that during catheterization of the lymphatic vessel of the lower extremity in anesthetized animals, the lymph does not flow out.

Many different mechanisms and factors are involved in the regulation of lymph movement, which is determined by the need to ensure the reliability of the functions performed by the lymphatic system. Lymph nodes have their own contractile activity similar to the lymphatic vessels. It is likely that the motility of smooth muscles contributes (and under certain conditions changes) the transport capacity of the lymph nodes. The movement of lymph through the node may be facilitated by arterial pulsation. The presence of good innervation and smooth muscles suggests the influence of the nervous system on the lymph flow through the lymph nodes.

Among the factors of lymph flow, the most significant after the own contractile activity of the lymphatic vessels are passive and active muscle movements, peristalsis of the gastrointestinal tract, pulsation of arteries and veins. The factors of lymph flow also include the influence of the frequency and strength of heart contractions on the lymph flow.

The lymph flow in the thoracic duct (the main collector of the vasculature of the lymphatic system) is affected by many constant factors (own contractile activity of the lymphatic vessels, respiration, blood pressure, aortic pulsation), the intensity of the influence of which can determine the movement of the lymph or contribute to it. Temporal factors (contractions of the skeletal muscles, the activity of the digestive system) can also largely determine the volume of lymph entering the venous system.

The high sensitivity of lymphatic vessels to thermal factors was noted. It has been proven that hypothermia reduces the tone of the lymphatic vessels by two and a half times. Hypokinesia has a particularly negative effect on the lymph flow. Massage enhances the transport function of the lymph. Dosed stimulation of lymph flow through passive movements of the injured limb with a certain frequency, duration and frequency significantly reduces the toxicity of peripheral lymph.

The lymphatic system is part of the vascular system, which successfully supplements the venous system and takes part in metabolism.

An important function of the lymphatic system is the removal of foreign bodies from the circulatory system, as well as the cleansing of tissues and cells. From the tissues of the organs, the fluid first enters the lymphatic system, where it is filtered by the lymph nodes, and then the lymph through the large vessels enters the thoracic lymphatic duct, where it flows from the chest into a large vein.

The lymphatic system consists of:

• Capillaries that form networks in all organs and tissues and are designed to remove fluid;
• Vessels formed from connections of capillaries. The vessels have valves, due to which the lymph moves in only one direction;
• Nodes that interrupt the vessels and divide them into vessels entering the node and leaving it. In the nodes, the lymph leaves all foreign bodies and microbes, and is also enriched with lymphocytes and is sent through other vessels to the thoracic lymphatic current and the right lymphatic current.

Other functions of the lymphatic system include:

• Retention of toxins and bacteria;
• Return of electrolytes and proteins from tissues to blood;
• Withdrawal of foreign bodies and red blood cells;
• Production of lymphocytes and antibodies;
• Transfer of products absorbed with food;
• Excretion of products through urine.

Organs of the lymphatic system:

• Bone marrow. All blood cells are created in it. Stem cells created in the myeloid tissue of the bone marrow enter the organs of the immune system.
• The spleen, which contains a large collection of lymph nodes. It breaks down dead blood cells. It reacts sharply to foreign bodies and produces antibodies.
• Thymus. It takes stem cells, turning them into T-lymphocytes (cells that destroy malignant cells and foreign bodies).

What does enlarged lymph nodes indicate?

Lymphadenopathy, or swollen lymph nodes, is quite common. For a healthy person, the norm is a slight increase in submandibular lymph nodes (no more than 1 cm), as well as an increase in inguinal lymph nodes (no more than 2 cm).

If the increase exceeds the allowable limits, a biopsy and additional research may be required. Enlarged lymph nodes of the lymphatic system may indicate the following diseases:

• On the sides of the neck - sarcoidosis, mononucleosis, tuberculosis and vaccination against it, as well as lymphoma and infections of the upper respiratory tract;
• In front and behind the auricles - rubella;
• Above the collarbone - tuberculosis, toxoplasmosis, stomach cancer (above the left collarbone);
• Under the lower jaw - gum problems or chronic tonsillitis;
• Under the armpits - hand infections, breast cancer, sarcoidosis;
• On the bends of the elbows - sarcoidosis;
• In the groin - inflammation of the genitourinary system or the presence of a specific infection (herpes, syphilis), infection of the legs.

Enlargement and inflammation of all groups of lymph nodes is an early symptom of HIV infection.

With lymphoma, the nodes become mobile and painless, and with metastases, they become soldered and dense.

Diseases of the lymphatic system

Any disease does not pass without a trace for all body systems. The lymphatic system reacts to the disease primarily by increasing the lymph nodes.

The main diseases of the lymphatic system are:

• Adenoids and chronic tonsillitis, when the tonsils cease to perform a protective function, becoming a source of infection. As a rule, with a long infectious process, they are removed.
• Acute lymphadenitis is an inflammation of the lymph node caused by bacteria. The disease is accompanied by redness, soreness, and sometimes suppuration. The disease rarely occurs alone, more often it occurs as a result of inflammation of the area through which the lymph flows.
• Chronic lymphadenitis. As a rule, this disease is a companion of other infectious diseases (syphilis, tuberculosis).
• Tumors of the lymphatic vessels. They can be either malignant (lymphangiosarcoma) or benign (lymphangioma).

Cleansing the lymphatic system

For the full functioning of the lymphatic system, at least a lot of movement is necessary. If a person leads a sedentary lifestyle, breathing exercises, exercises and long walks can help well. It is important to know that movement cleanses the body and eliminates lymph stagnation.

Cleansing of the lymphatic system is carried out through saliva, since the salivary glands are part of the general lymphatic system. The salivary glands draw out all dead cells and toxins from the body and bring them out through the gastrointestinal tract.

The easiest way to cleanse the lymphatic system daily is ginger. To do this, after eating, you need to dissolve, chew and swallow a piece of ginger. For the lymphatic system, this method is much more useful than a glass of water. Ginger irritates the mucous membrane and causes increased salivation.

The second way to cleanse the lymphatic system is juice. It is necessary to drink juice for several weeks, consisting of four parts of apple and carrot juice and one part of beetroot. It will be useful to add ginger root or ginger infusion to the juice.

The human lymphatic system (LS) is one of the structures that unite disparate organs into a whole. Its smallest branches - capillaries - penetrate most tissues. The biological fluid flowing through the system - lymph - largely determines the vital activity of the organism. In ancient times, drugs were considered as one of the main factors that determine a person's temperament. According to many doctors of that time, temperament directly determined both diseases and methods of their treatment.

The structure of the lymphatic system

Structural components of drugs:

• lymphatic capillaries and vessels;
• The lymph nodes;
• lymph.

The structure of the lymphatic capillaries and vessels

The LS in structure resembles tree roots, as well as the circulatory and nervous systems. Its vessels are located in all organs and tissues, except for the brain and spinal cord and its membranes, the internal tissue (parenchyma) of the spleen, inner ear, sclera, lens, cartilaginous, epithelial tissue and placenta.
Lymph is collected from tissues into blindly ending capillaries. Their diameter is much larger than that of the capillaries of the microvasculature. Their walls are thin and well permeable to liquid and substances dissolved in it, as well as to some cells and microorganisms.
Capillaries merge into lymphatic vessels. These vessels have thin walls with valves. The valves prevent the reverse (retrograde) flow of lymph from the vessels into the tissues. Lymphatic vessels braid all organs with a wide network. Often such networks in organs are represented by several layers.
Through the vessels, lymph slowly drains into groups of regional lymph nodes. Such groups are located at the “busy crossroads” of the body: in the armpits, in the elbows, groin, on the mesentery, in the chest cavity, and so on. Large trunks emerging from the lymph nodes flow into the thoracic and right lymphatic ducts. These ducts then open into large veins. Thus, the fluid removed from the tissues enters the bloodstream.

The structure of the lymph node

Lymph nodes are not only the "link" of drugs. They perform important biological functions determined by the peculiarities of their structure.
Lymph nodes are composed primarily of lymphoid tissue. It is represented by lymphocytes, plasma cells and reticulocytes. Important participants in immune processes, B-lymphocytes, develop and “ripen” in the lymph nodes. As they become plasma cells, they mediate humoral immune responses by producing antibodies.
T-lymphocytes are also present in the depth of the lymph nodes. There they undergo differentiation caused by contact with the antigen. Therefore, the lymph nodes are involved in the formation and cellular immunity.

The composition of the lymph

Lymph refers to the human connective tissue. It is a liquid substance containing lymphocytes. It is based on a tissue fluid containing water and salts and other substances dissolved in it. Also in the composition of the lymph there are colloidal solutions of proteins, giving it viscosity. This biological fluid is rich in fats. It is similar in composition to blood plasma.
The human body contains from 1 to 2 liters of lymph. It flows through the vessels due to the pressure of the newly formed lymphatic fluid and as a result of the contraction of muscle cells in the walls of the lymphatic vessels. An important role in the movement of lymph is played by the contraction of the surrounding muscles, as well as the position of the human body and the phase of respiration.

Functions of the lymphatic system

After considering the basics of the structure of drugs, its various functions become clearer:

• drainage;
• cleansing;
• transport;
• immune;
• homeostatic.

The drainage function of drugs is to remove excess water from tissues, as well as proteins, fats and salts. These substances then return to the bloodstream.
The drug removes many metabolic products and toxins from the tissues, as well as many pathogens that have entered the body. The barrier role is played by the lymph nodes: a kind of filters for the fluid flowing from the tissues. Lymph cleans tissues from the decay products of cells and microbes.
The drug carries immune cells throughout the body. It is involved in the transport of certain enzymes, such as lipases and other important substances. Unfortunately, metastasis of malignant neoplasms is also associated with the performance of drugs of their transport functions.
Lymph nodes are the most important participants in immune processes, ensuring the development of T- and B-lymphocytes. In this regard, small lymph nodes located in the intestinal wall (Peyer's patches) and areas of lymphoid tissue in the tonsils of the pharyngeal ring should be mentioned.
Participating in all these processes, the drug performs its integrating, homeostatic function, ensuring the invariance of the internal environment of the body.

Lymphatic system (LS) is a set of thin lymphatic vessels passing through the entire body.

The LS is similar to the circulatory system - there are blood vessels in all parts of the body, as well as blood-carrying veins and arteries. However, the vessels of the LS are much thinner and a colorless liquid, the lymph, is transmitted through them.

Lymph It is a clear liquid containing a large number of lymphocytes (white blood cells). Plasma seeps out of the capillaries, surrounds and washes the tissues of the body, and then flows into the lymphatic vessels.

After that, the fluid, which by that time becomes lymph, passes through the lymphatic system into the largest lymphatic vessel - the thoracic duct, after which it returns back to the circulatory system.

The lymph nodes

Along the lymph vessels are small bean-shaped lymph glands, also called lymph nodes. Some of them are easy to determine by palpation.

Lymph nodes of this kind are present in many parts of your body, including:

• In the armpit;
• In the groin;
• In the neck.

There are also lymph nodes that cannot be determined by palpation. They are located:

• In the abdominal cavity;
• In the pelvic region;
• In the chest.

Other organs of drugs

In addition to the lymphatic vessels and lymph nodes, the LS includes the following organs:

• the spleen;
• thymus gland;
• tonsils;
• Adenoids.

The spleen is located in the left hypochondrium. It consists of two different types of tissue: red pulp and white pulp. The red pulp filters worn out and damaged red blood cells and then recycles them. The white pulp contains a large amount lymphocytes And T-lymphocytes. These are white blood cells that play an important role in fighting various infections. When blood passes through the spleen, lymphocytes react to any sign of infectious diseases, starting to actively resist them.

(or thymus) is a small gland located under the sternum. It is involved in the reproduction of white blood cells. As a rule, the thymus is most active during adolescence, in the process of growing up, activity decreases.

tonsils are two glands located at the back of the larynx. tonsils And adenoids(the so-called “nasopharynxes” of the tonsils) help protect the entrance to the digestive system and lungs from viruses and bacteria.

Adenoids are located on the vault of the nasopharynx, somewhat closer, most often, to its back wall.

LAN functions

The human lymphatic system performs several functions.:

• Ensuring the flow of fluid from the tissues back into the blood;
• Lymph filtration;
• Blood filtration;
• Fight against infectious diseases.

Drainage of fluid into the blood

In the process of blood circulation, plasma leaks from the blood vessels into the tissues of the body. This fluid is very important, it has a dual function: it provides food for the cells and removes waste back into the bloodstream. The spent plasma drains into the lymph vessels and passes through them to the base of the neck, where it is cleaned and returned to the bloodstream. This circulation of fluid through the body occurs continuously.

Lymph filtration

As fluid passes through the lymph nodes, it is cleared. White blood cells attack any viruses or bacteria they find. If the patient is susceptible to oncological diseases and the tumor begins to metastasize, the separated cancer cells are often filtered out by the nearest lymph nodes. That is why doctors first check the lymph nodes for the presence of metastases in them, this allows you to determine how far the cancer has spread.

Blood filtration

This function is performed by the spleen. As the blood passes through this organ, any worn out or damaged red blood cells are removed from the blood, which are subsequently destroyed by the spleen. They are replaced by new red blood cells produced by the bone marrow. In addition, the spleen filters out bacteria, viruses and other foreign particles contained in the blood - the white pulp containing white blood cells is responsible for this.

Fight against infectious diseases

This function of the drug is, in fact, an important part of the immune response. One of the primary signs of an infectious disease is enlarged lymph nodes. The drug fights infection in the following ways:

• Participates in the creation of white blood cells (lymphocytes) that produce antibodies;
• The lymph nodes contain special blood cells - macrophages. They absorb and destroy any foreign particles, such as bacteria.

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