A small, organized structure of the lymphatic system that filters lymph and provides a site where immune cells can detect and respond to foreign substances.
Lymph nodes are distributed throughout the body and are connected by lymphatic vessels. As lymph passes through a node, microorganisms, abnormal cells, cellular debris, and other foreign material can be trapped or processed, allowing immune cells to respond.
Lymph nodes can become enlarged or tender when immune activity increases, such as during an infection. Enlarged lymph nodes can also occur for other reasons, including cancer and certain inflammatory conditions.
QUICK FACT
A swollen lymph node does not automatically mean cancer. Infection and other immune responses are common causes of lymph-node enlargement.
COMMONLY CONFUSED WITH
Lymphatic vessel: A lymph node is a lymph-filtering immune structure; a lymphatic vessel is a tube that transports lymph through the lymphatic system.
SEE ALSO
- Lymphatic System
- Lymphatic Vessel
- Lymphocyte
- Immune Cell
- Immunity