Lymphoid organs form part of the body’s immune system. Lymphoid organs defend the body against invading pathogens that cause infections or spread of tumors. These organs exist as primary, secondary or tertiary, based on the stage of lymphocyte development and maturation the organ is involved in.
The primary lymphoid organs serve to generate lymphocytes from immature progenitor cells. Progenitor cells possess the capacity to differentiate into a specific cell type. Progenitor cells divide for a limited number of times, depending on the need of the body.
Secondary lymphoid organs take charge of maintaining mature but naive lymphocytes. These organs initiate adaptive immune response.
Examples of secondary or peripheral lymphoid organs include adenoids, the tonsils, lymph nodes, Peyer’s patches, the spleen, and even the skin, among others.