Lymph Nodes

A lymph node is a small bean-shaped structure that forms part of the lymphatic system. Lymph nodes are found throughout the body, particularly in places where lymph vessels unite. 

The lymph nodes have three main functions: (1) to filter out and destroy foreign substances, such as bacteria and dust; (2) to produce some of the white blood cells called lymphocytes; and (3) to produce antibodies to help in the body's immune system. 

Specialized lymphoid tissue, similar to lymph nodes, includes the tonsils, adenoids, appendix, spleen, and areas of the body such as the Peyer's patches in the wall of the small intestine.