The lymphatic system for a long time remained poorly understood, nothing was known about its role. Meanwhile, it is very necessary in the body. The lymphatic system cleanses the body of substances that cannot be absorbed from tissues directly into the blood - these are colloidal solutions of proteins, emulsions of fats, suspensions of bacteria and cell breakdown products. All this is collected in the lymph, and then together with it flows into the bloodstream. Lymph contains a large number of lymphocytes - a special type of blood cells. These cells neutralize microorganisms and cancer cells.
The lymphatic system consists of lymphatic vessels, lymph nodes and lymphoid organs. Lymphoid organs include the spleen, tonsils, thymus gland. Unlike closed blood capillaries, lymphatic origin directly in organs and tissues. In the lymphatic capillaries, there are lymphatic vessels. Like veins, lymphatic vessels have valves that direct lymph flow in one direction. All lymphatic vessels collect lymph from the entire body and flow into the thoracic and right lymphatic ducts.
On the way of the lymphatic vessels are the lymph nodes. These are real antimicrobial filters in the body. A large number of lymphocytes are concentrated in the lymph nodes - blood cells that are actively fighting the infection. Once microorganisms appear near the lymph node, they are immediately attacked and neutralized by lymphocytes. If there are a large number of microbes, the lymph nodes increase in size. Such nodes can be easily palpated under the skin. This happens, for example, with a cold or inflammation of the periosteum of the tooth. There are many lymph nodes in the human body and it is almost impossible to determine their number at least approximately. Lymph nodes are located in groups of several nodes, near venous blood vessels.
In total there are about 150 regional groups of nodes. The largest of them are the lymph nodes in the groin, in the axillary region, the elbow, popliteal, submandibular, cervical, occipital, iliac, celiac, mediastinal nodes and others. The nodes located inside the chest or abdominal cavity are called visceral, and those located superficially - parietal.
Normally, the lymph nodes are not palpable. Enlarged lymph nodes occur in various diseases and serve as an important diagnostic symptom. In inflammatory diseases, the enlarged lymph nodes are palpated in the form of small mobile, painful, rounded seals about one centimeter in diameter. It is impossible to palpate enlarged visceral lymph nodes. The increase in nodes occurs near the focus of inflammation. After the course of treatment, the nodes are reduced in size, become invisible and painless.
Lymph nodes increase and with malignant processes. In this case, the nodes become dense, motionless, painless, fused with the surrounding tissues. This symptom develops with cancer, leukemia, lymphogranulomatosis.
In lymphoid organs, maturation of lymphocytes occurs. In addition, old red blood cells are destroyed in the spleen, for which it is often called their cemetery. Of a significant amount of lymphoid tissue, tonsils, appendix or appendix are made up of tonsils. Lymphoid tissue is located in the walls of the stomach, small and large intestine. With age, the amount of this tissue in the body gradually decreases, which is accompanied by a decrease in the reactivity of the immune system, an increase in the incidence of disease.