Function of the lymph vessel system

The lymph vessel system has two major tasks. The first task is to maintain metabolic transport and the corresponding distribution in the body. The lymphatic fluid transports fats that are absorbed in the intestines. The second task is the protective function against pathogens. In the lymph nodes, the “control points” of the lymph vessel system, the pathogens are fought by defense cells.

Tasks in the regulation of the metabolism

A considerable amount of fluid present in the body is transported back and forth via the lymphatic fluid. The parallel blood vessel system carries blood under sometimes high pressure and it always happens that fluid diffuses out of the vessel system. If this fluid were not removed, water retention would occur.

The lymphatic system absorbs this liquid that is left between the cells and carries it back through the entire lymphatic vessel system to the vein angle where it is returned to the blood vessel system. The transport of fats also takes place partially via the lymph vessel system. Fats that are important for the metabolism are absorbed with food. In order for these to reach the blood, the lymphatic fluid, which passes the intestine, absorbs these fats and transports them through the entire lymphatic vessel system to the venous angle, where the fat is returned to the blood system and distributed throughout the body, making it available to the cells for metabolism.

Function of the lymph vessel system in the defense against pathogens

The probably best known task of the lymphatic vessel system is the immunological response to pathogens that enter the body. The first hurdle is the skin barrier, which should initially prevent pathogens from entering the body. Mucous membranes also contain defense cells and antibodies.

Another filtering station is the lymph vessel system. If the pathogens reach this point, the lymph vessel system absorbs the pathogens to prevent them from entering the bloodstream directly. At each lymph node station, the lymph vessel system now tries to eliminate the pathogens.

For this purpose, there are numerous lymph nodes at each lymph node station. If the lymph nodes have to deal with a pathogen, they swell and can hurt. However, the superficial lymph nodes, which are sometimes noticed as painful swellings on the neck, for example during a flu, are only a small part of the lymph node system.

Most lymph nodes are deeper and cannot be palpated from the outside.Nevertheless, palpation of the important superficial lymph node stations often provides important diagnostic information. If the pathogens survive this first filtering station, they continue to swim through the lymph vessel system, perhaps even in smaller numbers, and soon reach the next lymph node station, where another defense process is started. The pathogens should be largely eliminated before they can enter the vein angle close to the heart.

If the lymph fluid has not been completely cleansed and the pathogens enter the blood vessel system, life-threatening sepsis can occur, which urgently requires antibiotic treatment. However, most pathogens are successfully eliminated. Especially small amounts of pathogens that enter the body, e.g. through a skin incision, usually do not pose a danger to humans.