Lymphatic System Definition & Image

© Copyright Bee Wilder, Revised February 2011.

When people refer to swollen glands in the neck or under the armpits, they are referring to swollen lymph nodes, which are part of the lymphatic system. You have probably seen your own lymph, which is a fluid; if a cut has ever oozed a clear fluid, that was lymph.

The lymphatic system is a drainage system, collecting and returning intestinal fluids. As with the blood network (circulatory system) the lymph vessels form a network of very small vessels throughout the body. The main parts of the lymphatic system are bone marrow, lymph nodes, the thymus gland, tonsils, spleen, etc. as shown in this image:

However, unlike the blood, the lymph system does not have a pump to move it like the heart does for the circulatory system. It is a one-way street draining lymph from the tissues and returning it to the blood. The only way to move the lymphatic system is by exercise, and when you are unhealthy you should only do Mild Forms of Exercise.

This system is a network of capillaries (tiny blood vessels) and tubes called lymphatics, which are found in every part of the body except the central nervous system. The functions of the lymphatics are to drain lymph (lymph is composed of water, protein, salts, glucose, and other substances) from all over the body, filter fluid from around the cells and returning it to the blood stream, and the absorption of fats from the intestines that it delivers to the bloodstream.

Lymph nodes are filters for lymph and may range in size from very tiny to 1 inch in diameter. They can be found in groups located in different areas of throughout the body, including the neck, armpit, chest, abdomen, pelvis and groin. Approximately two thirds of all lymph nodes and lymphatic tissue are within or near the gastrointestinal tract.