Lymphatic System Definition Explained

The lymphatic system is a network of vessels, lymph nodes, lymph ducts, and organs that move lymph across the body. The spleen, thymus, tonsils, and adenoids are the glands of the lymphatic system. The lymphatic system is part of and works with the immune system to fight infection and destroy pathogens. It’s primary functions are immunological defense, fluid balance, and fat absorption. When the lymphatic system isn’t working properly it can lead to backed up lymph fluid, ineffective lymph filtration, swollen lymph nodes, lowered immunity, and in extreme cases, cancer.

What is lymph?

Some of the fluid squeezed out via the capillaries, known as extracellular fluid, gets swept in by the lymphatic system. Once inside the lymphatic vessels, this fluid is known as lymph. Water, protein, glucose, electrolytes, and enzymes are some of the components that make up lymph fluid. One of the main functions of the lymphatic system is to filter lymph and return it to the blood. Bacteria can also get swept into the lymphatic system. When this occurs, the bacteria is deposited in the nearest lymph node where it will be destroyed by white blood cells (lymphocytes).

What are lymph nodes?

lymph_node_structureLymph nodes are small sacks, about .5-1 cm long, located throughout the body. There are about 500-700 nodes located throughout the body. The size of a lymph node varies depending on the area of the body it’s located in and the activity going on inside it. Higher concentrations of lymph nodes exist around the ears (cervical), in the underarms (axillary), around the belly button (mesentery), and in the groin (inguinal). Lymph nodes house lymphocytes and also help with the filtration of lymph. 

Swollen lymph nodes

lymph nodesWhen lymph nodes swell, it is most often an indication of infection. The flu virus, strep throat, or a sinus infection are some of many common infections that can cause swollen lymph nodes. When the lymphatic system detects an infection, it produces a larger amount of lymphocytes than usual. The lymph node will expand to house the excess of lymphocytes. Lymph node swelling should subside on it’s own after 1-2 weeks. If swelling does not subside, you should seek medical attention. Antibiotics may need to be prescribed for stronger infections. In some rare cases, swollen lymph nodes may be an indication of cancer.

When lymph fluid does not circulate efficiently, it becomes denser until it reaches the consistency of cottage cheese. The lumpy fluid becomes harder to eliminate and causes a back up of lymph fluid in the lymph nodes. This also means that pathogens are not being eliminated and the immune system is compromised, this can lead to severe disease, including cancer.

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