It is made up of organs, vessels, lymph nodes and lymphatic tissue. They all participate in the body’s immune responses. Lymphoid organs are split into two groups:
– Primary or central. A process takes place called lymphopoiesis, which consists of the maturation of lymphocytes. They obtain specific receptors for each kind of antigen. The organs that belong in this group are the thymus (which matures T lymphocytes) and bone marrow (where B lymphocytes mature).
– Secondary or peripheral. They provide a fit environment for lymphocytes to comingle and come into contact with the antigen, causing an immune response. The organs involved in this process are lymph nodes, lymphatic tissue and the spleen.
This system works in the following manner: lymph is collected by lymphatic capillaries and is then taken to the lymphatic vessels. In our body, there are two major ducts that drain tissue, the thoracic duct and the right lymphatic duct. The former intakes lymph coming from over half of the body and its journey ends in the left subclavian vein; meanwhile, the latter facilitates the exit of lymph coming from the right part of the body and ends its journey in the right subclavian vein.
Lymph nodes are found throughout our entire body, but they are most abundant at the axillas (armpits), groin, neck and pelvis. They are formed by a tough capsule that has small nodules on it; these mix with the lymph vessels. On the inside, they have lymphoid tissue, which contains a vast amount of lymphocytes and phagocytes.
Lymph passes through the body through these nodes, which have entry and exit canals. In addition, lymph nodes catch germs after lymph has gone through and destroy them. However, if there are too many, the node becomes inflamed.
