Together with the bone marrow and spleen, the lymphatic system is one of the fundamental components of the immune system. It is a venous system, composed of vessels and lymph nodes through which it carries liquids throughout the body.

The lymphatic vessels are equipped with small valves that allow the lymph to flow in only one direction, the heart true. In this way the vessels are able to drain the lymph in all tissues, even between the capillaries and in the space between the cells. The capillaries absorb most of the liquid, while what remains passes from the lymphatic vessels to the veins.

The sap contains:

• protein;
• minerals;
• various types of nutrients;
• damaged and sometimes cancer cells;
• bacteria and viruses,
• which penetrate from vessels to different tissues.

The lymph nodes collect all the lymphatic vessels and are positioned in strategic areas of the body. Their job is to eliminate potentially dangerous cells, thanks to the specialized leukocytes that destroy them. In this way they reduce the risk of infections and tumors, which could start from there and spread throughout the body.

The lymphatic system can suffer from various disorders, both genetic and otherwise. The main causes are:

• obstruction of the lymphatic system. When the vessels are blocked, liquids accumulate and damage the tissues. Obstructions can be caused by scar tissue, radiotherapy, trauma;
• infection of the lymph nodes, which causes an expansion of the infection throughout the body;
• tumors, which can block lymphatic ducts or metastasize in lymph nodes.

Source: msdmanuals.com