What is the role of lymph nodes in the immune system?

Lymph nodes play a crucial role in the immune system primarily by filtering lymph fluid for pathogens. They are small, bean-shaped structures that are strategically located throughout the body, particularly in areas such as the neck, armpits, and groin. As lymph fluid circulates through the lymphatic system, it passes through these lymph nodes, where it is monitored for foreign substances like bacteria, viruses, and cancer cells.

Inside the lymph nodes, specialized immune cells, including lymphocytes (such as T cells and B cells), reside and are activated when pathogens are detected. This activation leads to the production of antibodies and the coordination of other immune responses, effectively allowing the body to respond to infections. Thus, the filtering function of lymph nodes not only helps identify and eliminate pathogens but also facilitates the adaptive immune response, making them essential to the overall functioning of the immune system.