What is the lymphatic system?
The lymphatic vaatstelsel or systema lymphare is the set of organs, vessels and tissues in the body of vertebrates that contains mainly lymphocytes and lymph and transported.
System
Lymphatic vessels pass into lymphatic vessels that converge into lymph nodes, these are mainly located in the neck, the abdomen, the collarbone, armpits and groin. Then comes all the lymph fluid through two large collection vessels behind the clavicle in the right superior vena cava. The purified lymph becomes reabsorbed into the bloodstream. The left-hand collection vessel is much larger than the right because it processes the lymph coming from both legs.
The system is part of the venous circulation and acts as a drainage system of the body that starts and ends in the lymphatic vessels in large veins. The system is of great importance in the immune response in the human body, the prevention of an auto-immune response, the transport of blood cells, degradation and maturation of lymphocytes, as well as the cleaning of the blood. The system performs an immune defense function of the body by the presence of lymphocytes in lymph nodes, which are brought via the lymph and the large chest tube into the bloodstream.
The lymphatic system is located substantially parallel to the blood vessels and is an open system, as opposed to the blood circulation. It is composed of lymph vessels, lymph vessels and lymph nodes. Lymph that has left the bloodstream, is sucked up from the extracellular space by the lymphatic vessels. Which transport lymph via the lymph nodes back into the blood stream. The spleen is not part of the lymphatic system, but performs a similar function in the vasculature.
Lymphocytes
The lymphatic contains lymphocytes, which belong to the leukocytes. The lymphocytes are involved in the immune response in the human body. There are T lymphocytes (who take their name from the thymus or thymus), B lymphocytes and cytotoxic T cells. These cells detect certain antigens (foreign substances). B-cells can present themselves via the MHC-complex after phagocytosis (the "eat") of foreign substances such as a bacterium or virus. The T-lymphocytes are able to kill the cell in question and / or provide information to the B-lymphocytes which change thereon back into plasma cells. These plasma cells produce immunoglobulins that attach again specifically to foreign substances.
B lymphocytes may also recognize foreign substances and start production of immunoglobulins. As a result, the foreign cells to be (or virus-containing cells) again recognized by T-cells that make them harmless. This process of recognition and learning of the B-cells occurs in the lymph nodes via complex signaling systems. To prevent an attack by the body's own cells to lymphocytes found in the thymus, a process involving T lymphocytes that recognize antigens body instantly die before they are mature. For B lymphocytes applies a similar process of recognition. Impaired immune diseases can occur when this process goes wrong.
Deviations
The lymph nodes may be of interest for the diagnosis of certain infectious diseases. Further, the lymph nodes are places where metastasis of cancer can arise. Cancer cells can sometimes spread through the lymphatic vessels, and cause metastases in the lymph node. The first station to which a malignancy spreads, is called the sentinel lymph node. If a biopsy (tissue piece removed by needle or something similar) from a sentinel node is "negative", this means that no malignant (unrestrained dividing) cells are found. The chances of the cancer in such a case is elsewhere spread is very small.
In addition, there are numerous other abnormalities to a lymph node or lymph vessel possible. Some inflammation of hand or foot one sometimes sees a red stripe on the hand or leg to walk upstairs because a lymphatic vessel has become infected; This is called lymphangitis. After an operation for various kinds of cancers, including breast cancer, which sometimes is removed a large number of lymph nodes from the armpit or groin, the lymphatic drainage may be impaired, resulting in a permanent thick arm or leg on that side; this causes a build-up, which is called a lymphedema.
In the lymphatic system itself may also arise cancer (lymphoma). A distinction is made between Hodgkin's disease and non-Hodgkin lymphoma (NHL).