The lymphatic system is a system of lymph nodes, vessels and organs that runs throughout the body, and often seems mysterious and elusive as it does not receive the same attention as other body systems, like the cardiovascular or digestive systems.
People may be aware of lymph nodes in the neck when they become swollen with a sore throat or infection. The lymphatic system is a very important part of the body serving many life-preserving functions.
What makes up the lymphatic system?
The lymphatic system is made up of:
- Lymph nodes: these are small, bean-shaped organs found throughout the body
- Lymphatic vessels: the vessels circulate lymphatic ﬂuid (also called lymph) throughout the body
Organs of the lymphatic system:
- Bone marrow
- Thymus gland
- Lymphocyte accumulations in the lining of the intestinal, respiratory, genital and urinary
How does the lymphatic system work?
The lymphatic system has three main functions that include:
- To circulate and regulate ﬂuid levels in the body. Any excess ﬂuid that escapes from the bloodstream is picked up by the lymphatic system and returned to the bloodstream. This helps to prevent oedema (swelling due to excess ﬂuid) and keeps the ﬂuid levels in the body and the bloodstream within normal limits.
- To absorb fats from the digestive system. Special lymph vessels, called lacteals, are located in the lining of the digestive system where they are responsible for absorbing fat and fat-soluble vitamins from food. The fats are then transported to the bloodstream and used as needed.
- To defend the body against infection. The vessels of the lymphatic system move lymphatic ﬂuid and lymphocytes, a speciﬁc type of white blood cell, throughout the body. The lymphatic ﬂuid travelling through the lymphatic vessels passes through lymph nodes, which are primarily made up of lymphocytes. The lymphocytes serve to ﬁlter the lymphatic ﬂuid of any debris, removing bacteria, viruses and other foreign substances. This helps keep the body free of invading organisms and therefore, free of infection.