Function of the lymphatic system
Thus, the lymphatic system serves not only to remove foreign bodies or pathogens, but also to remove fluid from the tissue. If this evacuation does not function properly (for example, because there is an obstruction or insufficiency in the lymph vessels), fluid accumulates in the tissue, which in the worst case can lead to lymphedema.
Tasks of the lymphatic system
The lymphatic system absorbs water from the tissue and transports it to the heart and thus back into the circulation. Together with the water, fats, metabolic products and other substances are transported. In addition, the reabsorbed lymph at the so-called lymph nodes is checked for possible pathogens by cells of the immune system.
Thus, the lymphatic system plays an important role in the transport of substances and a central role in the defence against disease. In the human body, tissue is supplied with nutrients and oxygen by the finest blood vessels, so-called capillaries. The walls of these capillaries are permeable, so that part of the liquid in the blood can pass into the tissue together with the nutrients it contains.
The red blood cells, on the other hand, remain completely within the capillaries due to their size.Together with the metabolic and waste products of the tissue cells, a large part of this fluid also returns to the blood vessels, which, as veins, transport the blood towards the heart. However, about 10% of the fluid that leaks from the vessels cannot be absorbed for physical reasons and would therefore remain permanently in the tissue. Since this is about two liters per day, growing water retention would be the consequence.
The lymphatic system, however, prevents this by absorbing excess water in the tissue and returning it to the circulation at the heart. It can also transport large and particularly lipophilic substances. These cannot normally pass through the blood vessel walls.
Particularly important here are dietary fats absorbed in the intestine, which are transported in the lymphatic system as microscopic fat bubbles, so-called chylomicrons. Another important task of the lymphatic system is the defence against disease. The entire resorbed lymph must pass through at least one lymph node before it can reach the bloodstream again.
The lymph nodes contain a large number of cells of the immune system that can recognize and fight pathogens. Most of the immune cells are lymphocytes. These cells belong to the so-called adaptive immune response.
They are capable of attacking and eliminating pathogens with which the body has already had contact. Lymph nodes are distributed throughout the body, but are particularly common in certain regions. These include the lateral neck, the armpits and the groin. The internal organs also have their own lymph node stations along the spinal column.
