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Structure of the lymphatic system
Last reviewed: 23.04.2024
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The lymphatic system (systema lymphaticum) includes capillaries branched in organs and tissues, lymphatic vessels, lymph nodes that are biological filters for the tissue fluid, and also lymphatic trunks and ducts. On the lymphatic vessels, the lymph (tissue fluid) from the place of its formation flows to the junction of the internal jugular and subclavian veins that form the venous angle to the right and left in the lower parts of the neck.
The lymphatic system performs the most important protective functions in the body - it filters the tissue fluid (through the lymph nodes) and returns it (purified) to the blood, and then back to the organs and tissues. With the help of the lymphatic system, the organs and tissues remove particles of dead cells and other tissue elements, large-dispersed proteins that can not pass through the walls of the blood capillaries, as well as foreign particles and microorganisms found in the human body.
According to the structure and functions in the lymphatic system, lymphatic capillaries (lymphocapillary vessels) are isolated. They absorb the tissue fluid, which, together with the crystalloids dissolved in it, the products of metabolism in the lymphatic capillaries is called lymph (from the Latin lympha - pure water). By its composition, lymph is practically not different from tissue fluid. It is colorless, there is a certain amount of lymphocytes in it, macrophages are found.
On lymphatic vessels, lymph from capillaries along with the substances contained in it flows to the regional lymph nodes corresponding to this organ or part of the body, and from them to large lymphatic vessels - trunks and ducts. Lymphatic vessels can serve as ways of spreading infection and tumor cells.
Lymphatic trunks and lymphatic ducts are large collector lymphatic vessels, through which lymph from the regions of the body flows into the lower parts of the neck - into the terminal sections of the subclavian or internal jugular vein or into the venous angle - the site of the fusion of these veins. As a result of this fusion, the right (left) brachiocephalic vein is formed.
The lymph flowing through the lymphatic vessels to the lymphatic trunks and ducts passes through the lymph nodes that perform barrier-filtration and immune functions. In the sinuses of the lymph nodes, lymph is filtered through the loops of the reticular tissue.
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