THYMUS (ADJECTIVE THYMIC)

a lymphoid organ located in the chest behind the sternum. The thymus is a source of T-lymphocytes in children, but generally shrinks during adolescence. The thymus is the site of T-lymphocyte differentiation, where the cells learn to recognize antigens. The thymus produces some 30 hormones or thymic factors (e.g., thymodulin, thymopentin, thymostimulin) that are involved in the regulation of immune function.