Diseases of human lymphatic vessels. Lymphatic vessels: structure, functions and location Efferent lymphatic vessels

With the first information about anatomical formations, containing a colorless liquid, can be found in the works Hippocrates and Aristotle. However, these data were consigned to oblivion, and the history of modern lymphology begins with the work of the famous Italian surgeon Gasparo Azelli (1581-1626), who described the structure of the “milky vessels” - vasa lactea - and expressed the first thoughts about their functions.

Development of lymphatic vessels

Lymphatic vessels form in the early stages of fetal development and play a humoral transport role in the fetus-mother system. A newborn baby has an extremely developed lymphatic system in all internal organs, and its skin is equipped with many terminal lymphatic vessels and does not immediately lose its exceptional absorption ability. On this amazing fact a special lymphotropic therapy for newborns according to S.V. Gracheva. And we need to remember that the approach to skin hygiene and the products used for this in infancy should be the strictest.

Functions of lymphatic vessels

Lymphatic vessels serve only for the drainage of lymph, that is, they act as a drainage system that removes excess tissue fluid. To avoid reverse (retrograde) fluid flow, there are special valves in the lymphatic vessels.

Lymphatic capillaries

From the intercellular substance, waste products enter the lymphatic capillaries or crevices that end blindly in the tissue, like the fingers of a glove. Lymphatic capillaries have a diameter of 10-100 microns. Their wall is formed by fairly large cells, the spaces between which function like gates: when they open, components of the interstitial fluid enter the capillaries.

Structure of the vessel wall

Capillaries transform into postcapillaries with a more complex wall structure, and then into the lymphatic vessels. Their walls contain connective tissue and smooth muscle cells, and they contain valves that prevent the reverse flow of lymph. In large lymphatic vessels, valves are located every few millimeters.

Lymphatic ducts

Next, the lymph enters large vessels that empty into the lymph nodes. Having left the nodes, the vessels continue to enlarge, forming collectors, which, when connected, form trunks, and those - lymphatic ducts flowing into the venous bed in the area of ​​the venous nodes (at the confluence of the subclavian and internal jugular veins).

Like a spider's web, lymphatic vessels penetrate the internal organs, acting as a continuously working “vacuum cleaner”.

Number of lymphatic vessels in tissues

However, their representation in various bodies is uneven. They are absent in the brain and spinal cord, eyeball, bones, hyaline cartilage, epidermis, and placenta. There are few of them in ligaments, tendons, and skeletal muscles. A lot - in subcutaneous fatty tissue, internal organs, joint capsules, serous membranes. The intestines, stomach, pancreas, kidneys, and heart are especially rich in lymphatic vessels, which are even called the “lymphatic sponge.”

Lymphatic capillaries are the initial link of the lymphatic system. They are present in all human organs and tissues, except for the brain and spinal cord, their membranes, the eyeball, the inner ear, the epithelium of the skin and mucous membranes, spleen tissue, bone marrow and placenta.

The diameter of the lymphatic capillaries is 0.01-0.02 mm. The capillary wall consists of a single layer of endothelial cells, which are attached to adjacent tissues by special outgrowths - filaments. Lymphatic capillaries, connecting with each other, form lymphocapillary networks in organs and tissues.

The capillary wall has a selective ability to various substances. Increased lymph formation occurs under the influence of certain substances called lymphogenic (peptones, histamine, extracts from leeches).

Lymphatic capillaries are highly permeable to many cells and substances. Thus, red blood cells, lymphocytes, chylomicrons, and macromolecules easily penetrate the lymphatic capillaries, so lymph performs not only transport, but also protective functions.

Lymphatic vessels

Lymphatic vessels are formed by the fusion of lymphatic capillaries.

The walls of lymphatic vessels consist of three layers. The inner layer consists of endothelial cells. The middle layer consists of smooth muscle cells (muscle layer). The outer layer of lymphatic vessels consists of a connective tissue membrane.

Lymphatic vessels have valves, the presence of which gives the lymphatic vessels a distinct appearance. The purpose of the valves is to allow lymph to pass in only one direction - from the periphery to the center. Depending on the diameter of the lymphatic vessel, the distance of the valves from each other is from 2 mm to 15 mm.

Lymphatic vessels from internal organs and muscles usually exit with blood vessels - these are the so-called deep lymphatic vessels. Superficial lymphatic vessels are located next to the saphenous veins. In moving places (near the joints), the lymphatic vessels bifurcate and reconnect after the joint.

Lymphatic vessels, connecting with each other, form networks of lymphatic vessels. In the walls of large lymphatic vessels there are small blood vessels that supply blood to these walls, and there are also nerve endings.

The lymph nodes

Lymphatic vessels carry lymph from organs and tissues of the body to the lymph nodes. Lymph nodes act as a filter and play an important role in the body's immune defense.

Lymph nodes are located near large blood vessels, often venous, usually in groups of several nodes to ten or more. There are about 150 groups of lymph nodes in the human body. The number of nodes varies in different animal species: 190 in a pig, up to 8000 in a horse

Groups of lymph nodes lie superficially - under the skin layer (inguinal, axillary, cervical nodes, etc.) and in the internal cavities of the body - in the abdominal, thoracic, pelvic cavities, near the muscles.

The lymph node has a pinkish-gray color and a round shape. The dimensions of the lymph node range from 0.5 mm to 22 mm in length. The mass of all lymph nodes in an adult is 500-1000 g. On the outside, the lymph node is covered with a capsule. Inside it contains lymphoid tissue and a system of channels communicating with each other - lymphoid sinuses, through which lymph flows through the lymph node.

2-4 lymphatic vessels approach a lymphatic vessel, and 1-2 vessels leave it. On its way from each organ, lymph passes through at least one lymph node. Lymphatic vessels have a blood supply through small blood vessels; nerve endings approach the lymph nodes and penetrate them.

The role of lymph nodes. Each lymph node controls a specific area of ​​the lymphatic system. When microbes enter the body or foreign tissue is transplanted, the lymph node closest to this place begins to increase in size within a few hours, its lymphoid cells rapidly divide and form a huge number of small lymphocytes. The function of small lymphocytes is to organize the body’s specific self-defense (immune reaction) from foreign agents - antigens. Small lymphocytes are formed from bone marrow stem cells. In the lymph nodes, a distinction is made between long-lived thymus-dependent (T-lymphocytes), which have gone through stages of development in the thymus, and short-lived B-lymphocytes, which were not in the thymus, but went straight from the bone marrow to the lymph nodes.

Macrophages are the first to attack antigens that enter the body. T lymphocytes produce a special substance (humoral factor) that reduces the mobility of macrophages, due to which antigens are concentrated in the lymph nodes. There, the full power of the immune defense falls on them. One type of T-lymphocytes (killer cells) directly destroys antigens, another type of T-lymphodites (memory cells), after the first introduction of a foreign agent, retains the memory of it for life and provides a more active response to a secondary invasion. T lymphocytes, together with macrophages, “present” the antigen in such a way that this stimulates B lymphocytes to transform first into large lymphocytes and then into plasma cells that produce antibodies against the given antigen.

Thus, lymph nodes play an important role in both infectious and transplant immunity.

Age-related features of lymph nodes in humans:

Lymph nodes are located along the lymphatic vessels and together with them make up the lymphatic system. They are organs of lymphopoiesis and antibody formation. Lymph nodes, which are the first on the path of lymphatic vessels, carrying lymph from a given area of ​​the body (region) or organ, are considered regional.

In newborn children, the lymph node capsule is still very tender and thin, so it is difficult to feel them under the skin. By the age of one year, the lymph node can already be felt in almost all healthy children.

Most children aged 3-6 years have some hyperplasia of the peripheral lymphoid apparatus. Maslov M.S. pointed out that “lymphatism” is inherent mainly in the entire child population, and that to one degree or another, all children under 7 years of age are lymphatic. Vorontsov I.M. believes that young children may have various types of lymphatism that arise from overfeeding or due to repeated viral infections. However, in all situations, true lymphatic diathesis must be differentiated from accelerated, nutritional and immunodeficiency lymphatism. The prevalence of lymphatic diathesis in preschool children is 3-6%, and according to other data reaches 13%.

It is believed that normally, in healthy children, no more than three groups of lymph nodes are usually palpable. The chin, supraclavicular, subclavian, thoracic, ulnar, and popliteal lymph nodes should not be palpated. However, to date, the criteria for the norm and pathology of lymph nodes in childhood have not been fully developed and accepted in our country and widely recommended in the domestic literature, comparison of lymph nodes with the size of grain, peas, cherries, beans, hazelnuts or walnuts is irrational, because gives inconsistent results. According to the literature, in most children, cervical lymphadenopathy is of an infectious-inflammatory nature (92.5%), in 4.5% of cases it is tumor, and in 2.7% it is infectious-allergic. Moreover, the most common causative agent of nonspecific lymphadenitis in children is Staphylococcus aureus.

Age-related involutive changes (decrease in the amount of lymphoid tissue, proliferation of adipose tissue) in the lymph nodes are observed already in adolescence. Connective tissue grows in the stroma and parenchyma of the nodes, and groups of fat cells appear. At the same time, the number of lymph nodes in regional groups decreases. Many small lymph nodes are completely replaced by connective tissue and cease to exist as organs of the immune system. Lying lymph nodes nearby fuse with each other and form larger segmental or ribbon-shaped nodes.

In any case, the presence of palpable lymph nodes in a child, the size of which exceeds age norms, is an indication to clarify their nature. At the present stage, for this purpose it is possible to use technical means, primarily echography, i.e. examination method using ultrasonic waves.

Lymph nodes are rebuilt throughout life, including in older and older people. From adolescence (17-21 years) to old age (60-75 years), their number decreases by 1.5 - 2 times. As a person ages, in nodes, mainly somatic, the capsule and trabeculae thicken, connective tissue increases, and parenchyma is replaced by adipose tissue. Such nodes lose their natural structure and... properties, become desolate and become impassable for lymph. The number of lymph nodes also decreases due to the fusion of two nodes lying nearby into a larger lymph node. With age, the shape of the nodes also changes. At a young age, nodes of round and oval shape predominate; in elderly and old people, they seem to stretch out in length. Thus, in elderly and old people, the number of functioning lymph nodes decreases due to their atrophy and fusion with each other, as a result of which in older persons: large lymph nodes predominate.

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Lymphocapillary vessels constitute one of the links in the microvasculature. The lymphocapillary vessel passes into the initial, or collecting, lymphatic vessel, which then passes into the efferent lymphatic vessel.

The transition of lymphocapillary vessels into lymphatic vessels is determined by a change in the structure of the wall, and not by the appearance of valves, which are also found in capillaries. Intraorgan lymphatic vessels form wide-loop plexuses and go together with blood vessels, located in the connective tissue layers of the organ. From each organ or part of the body, drainage lymphatic vessels emerge and go to various lymph nodes.

The main lymphatic vessels, resulting from the fusion of secondary and accompanying arteries or veins, are called collectors. After passing through the last group of lymph nodes, the lymphatic collectors are connected into lymphatic trunks, corresponding in number and location to large parts of the body. Thus, the main lymphatic trunk for the lower limb and pelvis is truncus lumbalis, formed from the efferent vessels of the lymph nodes lying near the aorta and inferior vena cava, for the upper limb - truncus subclavius, running along v. subclavia, for the head and neck - truncus jugularis, running along v. jugularis interna. In the chest cavity, in addition, there is a paired truncus bronchomediastinalis, and in the abdominal cavity an unpaired truncus intestinalis is sometimes found. All these trunks eventually connect into two terminal ducts - ductus lymphaticus dexter and ductus thoracicus, which flow into large veins, mainly into the internal jugular.

The valves of the lymphatic vessels are paired folds (leaves) of the inner membrane, lying opposite each other. More than 300 years ago it was established that the valves in all lymphatic vessels have a crescent shape. However, the results of relatively recent studies have shown that these valves differ in both shape and size.

When studying lymphatic vessels using stereomicroscopic methods and scanning electron microscopy, it was found that most valves have a funnel shape.

According to M. S. Spirov (1959), the valves of intra- and extraorgan lymphatic vessels have different shapes. According to the author, in intraorgan vessels the valves actively participate in the flow of lymph as gateways, and in extraorgan vessels they open and close under the pressure of lymph on them.

Each valve has an edge attached to the wall of the lymphatic vessel at the level of its narrowed part, a free movable edge and two surfaces: internal and external. The inner (axial) surface, convex in shape, faces the lumen of the vessel, the outer (parietal) surface with its concave side is directed towards the wall of the lymphatic vessel at the level of its expansion.

The vascular space located between the parietal surface of the valve and the axial surface of the wall of the supravalvular expansion of the vessel is called the valve sinus. The valve leaflet is formed by a thin central connective tissue plate covered on all sides by endothelium.

In large-diameter lymphatic vessels, in the central connective tissue plate of the valves, in addition to collagen fibers, there are elastic fibers that serve as a continuation of the internal elastic membrane.

According to V.V. Kupriyanov (1969), there are no muscular elements in the valve leaflets, therefore the valves in the lumen of the vessels are capable of only passive movement. The valves are pressed against the wall of the vessel when lymph moves in the central direction and close, preventing the reverse flow of lymph.

Emptying of the intervalvular space of the vessel, sinus, is carried out, according to V.V. Kupriyanov, due to the contraction of the “muscular cuff”, thanks to which each intervalvular segment functions as a microscopic pressure pump.

The number of valves in a lymphatic vessel depends on its location. Thus, in lymphatic vessels starting from capillary networks, the distance between the valves ranges from 2 to 3 mm, in extraorgan vessels it reaches 6 - 8 mm, in large lymphatic vessels - 12 - 15 mm.

The distribution of valves in the same vessel in an organ depends on the regional characteristics of lymph flow. Up to 60 - 80 valves were found in the vessels running from the fingers to the axillary lymph nodes, 80 - 100 - in the superficial vessels of the lower limb.

"Extraorgan pathways of lymph transport"
M.R.Sapin, E.I.Borzyak

The circulatory system ensures constant circulation of blood and lymph. Thanks to this, organs and tissues are supplied with oxygen and nutrients, metabolic products are released from them, humoral regulation, etc.

The circulatory system consists of the heart and blood vessels: arteries, veins, capillaries. All this forms two circles of blood circulation: large and small, through which blood continuously moves from the heart to the organs and back. The systemic circulation begins with the aorta, which emerges from the left ventricle, carrying arterial blood to all organs of the body and ending with the vena cava. The lesser (pulmonary) circle begins with the pulmonary trunk, which emerges from the right ventricle and delivers venous blood to the lungs.

Rhythmic contractions (systole) and relaxations (diastole) of the heart move blood through the vessels. The heart is a four-chambered, hollow muscular organ consisting of two atria and two ventricles. Arterial blood flows in the left half (left atrium and left ventricle), and venous blood flows in the right half (right atrium and right ventricle).

Arteries are the vessels through which blood flows from the heart to the organs. Depending on the diameter, large, medium and small arteries are distinguished. And depending on their location in relation to the organ, intraorgan (intraorgan) and extraorgan (extraorgan) arteries are distinguished. The thinnest arterial vessels are called arterioles, which gradually turn into capillaries.

Capillaries are the smallest blood vessels. It is through their walls that all exchange processes between blood and tissues occur. Capillaries are collected in a network and connect the arterial system with the venous system.

Veins are vessels through which blood flows from organs to the heart.

The walls of arteries and veins are supplied with nerves and nerve endings.

Massage has a beneficial effect on the cardiovascular system. Thanks to the massage, blood from the internal organs moves to the surface of the skin and muscle layers. Due to this, the expansion of peripheral vessels occurs, and therefore the work of the left atrium and left ventricle is facilitated, the blood supply and contractility of the heart muscle are improved, and phenomena resulting from stagnation are eliminated in the pulmonary and systemic circulation.

Under the influence of massage, the number of functioning capillaries increases, capillary blood flow accelerates, blood supply to the massaged area increases, and tissue nutrition (trophism) improves. Since cell metabolism is revived, oxygen absorption by tissues increases. As a result of stimulating the hematopoietic function in the blood, the content of hemoglobin and red blood cells increases.

The reflex method of massage is widely known. At the same time, individual areas of the body are massaged, and an increase in skin temperature and an increase in blood flow is also observed in the non-massaged part.

Massage causes an increase in temperature, warming of tissues, changing their physical and chemical state, which improves elasticity.

Under the influence of massage, venous blood circulation improves, which in turn facilitates the work of the heart.

Massage may cause minor changes in blood pressure. Thus, it has been noted that massage of the head, neck, shoulder girdle and abdomen in patients with hypotension and hypertension also contributes to a slight decrease in systolic and diastolic pressure.

The lymphatic system is part of the cardiovascular system. It consists of networks of lymphatic capillaries, plexuses of lymphatic vessels and nodes, lymphatic trunks and two lymphatic ducts.

The lymphatic system is involved in removing excess interstitial fluid and returning it to the venous bed, in the absorption of colloidal solutions of protein substances from tissues that are not absorbed into the blood capillaries.

Lymphatic capillaries are found in all organs except the brain and spinal cord, spleen, cartilage, lens, sclera of the eyes, and placenta. Networks of lymphatic capillaries form lymphatic vessels.

Superficial lymphatic vessels carry lymph from individual areas of the body and flow into the nearest lymph nodes, which are hematopoietic organs and perform a barrier function. Lymph nodes also produce lymphocytes, a type of white blood cell that protects the body from infections and foreign substances.

Lymph, flowing from the periphery into the node, is filtered through the tissue of the node, leaving suspended particles (microbes, protozoan tumor cells, decay products) in it, which are captured by lymphocytes. When lymph circulation is delayed, it stagnates, swelling occurs. And the weakened movement of lymph causes a deterioration in the nutrition of tissues and cells, which leads to a decrease in metabolic processes.

Under the influence of massage, lymph circulation accelerates and the amount of lymph flowing from the massaged area increases by 6-8 times.

Lymphatic vessels with a large diameter, connecting with each other, form lymphatic trunks, which in turn merge into two large lymphatic ducts. Lymphatic ducts, which collect lymph from the whole body, flow into large veins in the neck.

The spread of inflammatory processes and the transfer of malignant tumor cells can occur through the lymphatic tract. Enlarged lymph nodes may indicate the presence of a particular disease.

The movement of lymph in the lymphatic system occurs in one direction - from tissues to the heart. Massage promotes the drainage of lymph from organs and tissues. Therefore, massaging movements are usually carried out along the lymphatic flow to the location of the nearest lymph nodes. Such directions are called massage lines or massage directions.

On the scalp, the direction of massaging movements runs from the crown downwards and to the sides to the location of the lymph nodes: the back of the head, near the ears, on the neck (Fig.)

When massaging the face, the massage lines are consistent with the direction of the drainage vessels running from the midline of the face to the submandibular and mental lymph nodes (Fig.).

Massage in the neck area is carried out from top to bottom. On the posterior surface - from the occipital region down along the upper edge of the trapezius muscle. On the lateral surfaces - from the temporal areas down. On the front surface - from the edge of the lower jaw and chin down to the sternum. Massaging movements are made in the direction of the supra- and subclavian and axillary lymph nodes.

As for massage in the torso area, the border of the lymphatic division of the superficial vessels of the torso is on the belt. Massage lines from the lateral, anterior and posterior surfaces of the body above the waist line extend to the subclavian and axillary lymph nodes. Areas of the body located below the waist line are massaged towards the inguinal lymph nodes (Fig.).

On the upper limb, the dorsal and palmar surfaces of the phalanges of the fingers are massaged transversely to their longitudinal axis. Massaging the lateral surfaces of the fingers is carried out longitudinally from the nail to the main phalanges. The palmar and dorsal surfaces of the metacarpus and wrist are massaged towards the wrist joint, and then to the ulnar lymph nodes. On the shoulder and forearm, massage lines are directed to the axillary and subclavian lymph nodes (Fig.).