What is a "lymph node"?

A lymph node is a small, bean-shaped organ found throughout the body, primarily in clusters along the lymphatic system. They are an integral part of the immune system, acting as filters for lymph fluid. Lymph nodes contain immune cells, such as lymphocytes and macrophages, which help detect and eliminate harmful substances, such as bacteria, viruses, and abnormal cells. When infection or inflammation occurs nearby, lymph nodes may enlarge and become tender as they work to combat foreign invaders. Lymph nodes play a crucial role in the immune response by trapping and destroying pathogens, facilitating the production of immune cells, and aiding in the coordination of immune system activities.