The lymphatic system involves a network of vessels and specialized tissues that regulate immune function in the body. It is a type of vascular “sewer” or “drainage” system that collects fluid and waste from tissues throughout the body, filters it, and brings it back into circulation. A healthy lymphatic system helps us stay healthy by preventing the accumulation of fluid (edema) in any particular part of the body and by killing off invading pathogens.
It’s Role in Circulation
Lymphatic vessels are dispersed throughout the body and collect excess fluid and waste from tissues and organs. This excess fluid can come from inflammation (from injury or infection) and from normal physiological function. Once in the lymphatic circulation, the collected fluid is called “lymph” which can contain leaked blood plasma, proteins, fats, minerals, cellular waste, and white blood cells.
During this process, lymph is filtered by the lymph nodes, where immune cells (like neutrophils and macrophages) kill pathogens and neutralize toxins. Fats and fat-soluble vitamins absorbed from the small intestine also make their way through the lymphatic system to be filtered before entering venous circulation.
It’s Role in Immune Function
Connected to most lymphatic vessels are a series of specialized immune tissues known as lymphoid organs. Lymphoid organs include bone marrow, thymus, adenoids, tonsils, lymph nodes, appendix, and many others. These organs are responsible for the production, maturation, and storage of immune cells known as lymphocytes, which are involved in both innate and adaptive immune responses.
By being connected to the lymphatic vascular network, most of these lymphoid organs are able to directly respond to injury and pathogens invading connective tissues. When part of the body becomes infected, the pathogen, its components, and antigen-presenting cells are drained into local lymph nodes to be killed and analyzed. We experience this when our tonsils and adenoids swell during an upper respiratory tract infection.
The best way to keep the lymphatic system healthy is by staying hydrated, eating well, and exercising plenty. Staying hydrated will ensure that fluid levels in the body are optimal for circulatory and immune function. Nutrients from a well-balanced diet ensure that the lymphatic vascular network is well maintained and that immune cells have the necessary raw materials to fight infection. The lymphatic system is not powered by a pump like circulation, but by body movement and muscle contraction. For this reason, exercise will ensure that there is optimal lymphatic flow. Acupuncture is also an ideal way to ensure that your body is primed and ready to fight disease.
- Parham, P., & Janeway, C. (2009). The Immune System (3rd ed.). London: Garland Science.
- Seffinger, M. A. (2018). Foundations of osteopathic medicine: Philosophy, science, clinical applications, and research (4th ed.). Philadelphia: Wolters Kluwer.