The tissues are distinguished in diffuse and lymph nodes. The diffuse tissue is represented by accumulations of lymphocytes, supported by a reticular stroma, scattered in various organs (omentum, mucosa of the alimentary canal, respiratory system, and urethra). In general, we speak of tissue associated with mucous membranes. It consists of lymph node tissue, organized into lymph nodes. Solitary lymph nodes present in various systems are recognized (intestinal canal, genital system) and lymphatic formations grouped in groups (tonsils) and hemolymphatic. Lymph node tissue is also widely represented in the spleen. The lymph nodes are interspersed along the course of the vessels.
They constitute a way of communication between the intimate structure of the various organs and venous blood. They originate with capillary nets that have different morphological characteristics in the individual organs.
The main ones are the thoracic duct, which originates from the confluence of the lumbar trunks in the cistern of Pecquet, the great vein which receives the lymph from the right supra-diaphragmatic half, the jugular trunk, the subclavian trunk, and the mediastinal trunk. The circulation of the lymph depends on the pressure exerted by the pressure of the interstitial fluid of the tissues and is activated by the respiratory movements, by the force of gravity and by the mechanical stresses exerted on the walls of the vessels, by the arterial pulsation and by the contractions of the somatic musculature. The valves with which the manifolds and trunks are supplied combine to regulate their direction.
Similarly to those of the cardiovascular system, the smaller lymphatic vessels, called capillaries, are located in the peripheral regions of the organism and, coming together, give rise to ever-larger vessels, up to pouring into the thoracic duct. Unlike the blood ones, the lymphatic capillaries are blind-bottomed and have an even thinner wall, formed by cells separated by large openings. The lymph carried by the thoracic duct, joining that present in the vessels coming from the upper part of the body, pours at the level of the conjunction between the subclavian veins and the jugular vein.
In correspondence with some junctions between the various lymphatic ducts, located in strategic points of the organism, we find real filtering stations called lymph nodes. Along with the lymphatic system, we also meet the so-called lymphatic organs, responsible for the production and purification of the lymph (thymus, spleen, and bone marrow).
Transparent, straw yellow, or milky color depending on the case, the sap contains sugars, proteins, salts, lipids, amino acids, hormones, vitamins, white blood cells, etc. Compared to blood, the lymph is particularly rich in lipids; the lipid molecules are poured into the lymphatic system in the form of particular lipoproteins called chylomicrons.
The larger lymphatic vessels are characterized by the succession of narrowing and dilations, which are associated with true valve insertions. Similarly to those of the venous system, prevent the reflux of the lymph by forcing it to flow in only one direction. The wall of some of these vessels also has the contractile ability. All these anatomical peculiarities are fundamental to allow the unidirectional passage of the lymph from the interstitial fluid of the tissues towards the systemic circulation.
The lymph derives directly from the blood and has a composition very similar to it, despite being richer in white blood cells and very poor in red ones. Circulating in the interstitial spaces (including, that is, between one cell and another), it has the purpose of reabsorbing the plasma (the liquid part of the blood) present in these areas. The very thin walls of the blood capillaries are, in fact, permeable to water and various substances; due to this permeability, oxygen, and nutrients can pass from the blood to the tissues which, for their part, pour carbon dioxide and waste products into the bloodstream. Lymph represents an effective system through which the body collects liquids and waste material from the periphery and then conveys it to the purification organs (liver, kidneys, lungs, lymph nodes). From this point of view, the function of the lymphatic system is very similar to that of the venous circle.
When the precious lymphatic drainage system goes haywire, considerable quantities of liquids can accumulate in the interstitial spaces due to the unfavorable osmotic gradient .This condition is called edema and, as mentioned, is the typical consequence of prolonged immobilization. In addition to inadequate lymphatic drainage, edema can be caused by an increase in capillary filtration compared to reabsorption; this condition is typical of some diseases such as heart failure and protein-calorie malnutrition (kwashiorkor).
- Drains fluid back into the bloodstream and proteins filtered by the blood capillaries to the circulation
- To transfer the absorbed fats in the small intestine to the systemic circulation
- capture and destroy pathogens foreign to the body, producing and transforming the cells responsible for their neutralization.
The lymphatic system is one of the body's natural defense systems against infections. It is a complex system consisting of lymphatic organs, such as the bone marrow, tonsils, thymus and spleen, and a series of lymph nodes, which are connected to each other by a network of thin lymphatic vessels. Lymph nodes are small glands located in the neck, in the armpits, and in the groin. Their number varies depending on the location and ranges from a few units to a few dozen, as in the case of axillary lymph nodes, present in a number between 20 and 50.
The tissues that make up our body produce a clear liquid called lymph, which is circulated throughout the body via the lymphatic vessels. Lymph contains white blood cells, called lymphocytes, which have the function of defending against infections and diseases. For example, when we have a sore throat, if we palpate the lymph nodes in the neck, we realize that these are enlarged. This is the sign that the body is struggling with an infection.
It is very important to carry out the regular physical activity to promote the action of the "muscle pump." When this healthy habit is associated with a balanced diet, the immune defenses maximize their effectiveness, thus preventing the lymphatic system from going haywire for too much work. There are also special massage techniques that help the lymphatic system to drain the liquid that stagnates in peripheral areas more effectively.