reticuloendothelial system (redirected from Mononuclear phagocytic system)

reticuloendothelial system

n. Abbr. RES

The diffuse system constituting all phagocytic cells of the body except granulocytes including the cells lining the sinusoids of the spleen, lymph nodes, and bone marrow along with the fibroblastic reticular cells of hematopoietic tissues.

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reticuloendothelial system (reˈ·ti·ky·lō·en·d·thēˑ·lē·l sisˑ·tm),

n a functional system of the body primarily involved in defending the body against infection and disposing the end products of cellular breakdown. It comprises the Kupffer cells within the liver; macrophages; and the reticulum cells of the bone marrow, lungs, lymph nodes, and spleen. Gaucher's disease, eosinophilic granulmoa and Niemann-Pick disease are due to dysfunctions in this system. Also called
RES.

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reticuloendothelial system

a term that encompasses the monocyte-macrophage or mononuclear phagocytic system and also includes reticulum cells. It consists of a population of cells called macrophages, which are of bone marrow origin and are widely distributed throughout the body. Immature macrophages or monocytes make up about 5% of peripheral blood leukocytes. Mature macrophages are found in connective tissue (histiocytes), lining hepatic sinusoids (Kupffer cells), in the lung (alveolar macrophages), brain (microglia) and skin (Langerhans cells). They are also found in the spleen, lymph nodes and bone marrow. The major roles of these cells include: phagocytosis, antigen-processing and trapping, regulation of immune responses and the secretion of several biologically important factors such as interleukin 1, lysozyme, plasminogen activator and complement components.

The macrophages of the spleen possess the ability to dispose of disintegrated erythrocytes. They do not, however, destroy hemoglobin, which is liberated in the process.

Kupffer cells, together with the cells of the general connective tissue and bone marrow, are capable of transforming into bile pigment the hemoglobin released by disintegrated erythrocytes.