GENERAL HISTOLOGY

Detailed explanation-1: -Secondary lymphoid organs: These organs include the lymph nodes, the spleen, the tonsils and certain tissue in various mucous membrane layers in the body (for instance in the bowel). It is in these organs where the cells of the immune system do their actual job of fighting off germs and foreign substances.

Detailed explanation-2: -Secondary lymphoid organs (SLOs) include lymph nodes (LNs), spleen, Peyer’s patches (PPs) and mucosal tissues-the nasal associated lymphoid tissue (NALT), adenoids, and tonsils.

Detailed explanation-3: -Secondary lymphoid organs filter extracellular fluids for antigens and microorganisms. They are the sites at which lymphocytes are activated by antigens, and subsequently develop into effector cells.

Detailed explanation-4: -Lymphocytes develop in the thymus and bone marrow (yellow), which are therefore called central (or primary) lymphoid organs.