ABSTRACT
The main functions of the lymphatic system are the production of immunocompetent cells and the draining and circulation of lymph from the tissues. Lymphoid organs can be divided into primary (bone marrow, thymus, and bursa in the avian species) and secondary (lymph nodes, spleen, and mucosal-associated lymphoid tissue, or MALT) and the lymphatic system produces and specialise cells to mount immune responses against antigens. The main histological features of the lymphoid organs, together with a description of immune cells, are described in this chapter.
