Lymph nodes are small but very important structures in the lymphatic system, which is part of the larger immune system in the body. These nodes act as filters, removing harmful particles and fighting off bacteria. Many people notice that some lymph nodes in their bodies become swollen when they get sick, because these structures are working overtime to produce more white blood cells to fight the infection. Swollen lymph nodes can also be symptoms of a more serious problem, like a cancer which has metastasized to the lymph nodes.

The lymph system is an extensive interconnected system which transports lymph, a clear to yellowish fluid, through the body. Lymph contains white blood cells called lymphocytes, along with certain proteins and some red blood cells. This fluid helps the body fight infection, and as it passes through the lymph nodes, these nodes pull infectious agents like bacteria out of the flow of lymph so that they do not continue to circulate through the body.

There are hundreds of lymph nodes throughout the body; when normally sized, the nodes are around the size and shape of a bean. A thick layer of fibrous tissue protects the inside of a lymph node, which resembles a honeycomb. This honeycomb design acts as a filter to pull out particles which are too large to pass through it. You can often feel your tonsillar lymph nodes, which are located just under your jaw.

Once a lymph node has neutralized a harmful substance, it can release it into the lymph system again so that the body can secrete it, along with other bodily wastes. Several schools of massage and bodywork such as lymphatic drainage are focused on stimulating the flow of lymph to help clients remove toxins from their body. Any type of bodywork which interacts with the lymphatic system requires special training, as a client could be accidentally injured by a bodyworker.

These nodes are sometimes called “glands,” despite the fact that they do not produce hormones or other fluids. Swollen lymph nodes are not necessarily a cause for alarm, as they indicate that your body is fighting an infection, and doing so with at least some success. However, when a swollen lymph node becomes extremely large or tender, it is a good idea to see a doctor. The contents of the lymph nodes are sometimes used as diagnostic tools to check for various conditions, and biopsies of surrounding lymph nodes are routinely taken when a cancer is identified, to ensure that the cancer has not spread into the lymphatic system.