Mononuclear phagocyte system

a widely distributed collection of both free and fixed macrophages derived from bone marrow precursor cells by way of monocytes, with mediation of substantial phagocytic activity by immunoglobulin and the serum complement system

Description
In both connective and lymphoid tissue, cells of the mononuclear phagocyte system may occur as free and fixed macrophages; in the sinusoids of the liver, as Kupffer cells; in the lung, as alveolar macrophages; and in the nervous system, as microglia. Syn system of macrophages