Lymph nodes

A lymph node is a small, bean-shaped organ that is part of the lymphatic system, which plays a crucial role in the body's immune response. Lymph nodes are secondary lymphoid organs distributed throughout the body, including areas such as the neck, underarms, chest, abdomen, and groin. They function as filters for lymph, a fluid that circulates through the lymphatic system, carrying immune cells, proteins, and other substances.

Lymph nodes are composed of a complex microarchitecture that includes various cell types, such as lymphocytes, macrophages, and stromal cells. These cells interact within the lymph node to initiate and regulate adaptive immune responses. The nodes are organized into distinct compartments, each supporting specific immune functions.

The primary role of lymph nodes is to filter lymph and trap pathogens, preventing their spread through the bloodstream. They also serve as sites where immune cells, such as T and B lymphocytes, are activated in response to antigens, facilitating the development of adaptive immunity.Additionally, lymph nodes are involved in processes such as peripheral tolerance and can play a role in disease states, including cancer metastasis.