Reticuloendothelial system 580852 224145939 2008-07-07T15:02:49Z 66.150.82.115 /* Function */ The '''reticuloendothelial system''' ('''RES'''), part of the [[immune system]], consists of the [[phagocytosis|phagocytic]] cells located in [[reticular connective tissue]], primarily [[monocyte]]s and [[macrophage]]s. These cells accumulate in [[lymph node]]s and the [[spleen]]. The [[Kupffer cell]]s of the [[liver]] and tissue [[histiocyte]]s are also part of the RES. '''Mononuclear phagocytic system''' and '''lymphoreticular system''' are synonymous with RES. The reticuloendothelial system is divided into ''primary'' and ''secondary'' lymphoid organs. ==Primary lymphoid organs== '''Primary''' (or '''"central"''') lymphoid organs - the sites where the cells of the RES are ''produced''. The cells of the RES are produced in the [[bone marrow]]. The [[thymus]] is also included as it is the required site for [[T cell]] maturation. ==Secondary lymphoid organs== '''Secondary''' (or '''"peripheral"''') lymphoid organs - the sites where the cells of the RES ''function''. This includes the [[lymph nodes]], [[tonsils]], spleen, and "MALT" ([[mucosa-associated lymphoid tissue]]). *MALT is further divided into the "GALT" ([[gut-associated lymphoid tissue]]) and the "BALT" (bronchus-associated lymphoid tissue). *The [[Kupffer cells]] of the liver act as part of this system but are not organized into a tissue; rather, they are dispersed throughout the [[liver sinusoid]]s. *The [[microglia]] of the [[Central Nervous System]] (CNS) can be considered a part of the reticuloendoethelial system. They are scavenger cells that proliferate in response to CNS injury. ===Function=== The secondary lymphoid structures function to survey all entering or circulating antigen and to mobilize an immune response against foreign antigen upon its discovery. The GALT and BALT are privy to a myriad of antigen entering the gastrointestinal and respiratory tracts, respectively. All extracellular fluid must filter through lymph nodes as it traverses the lymphatics on its way back to the systemic circulation. Antigen residing in the interstitium is thus swept to the lymph nodes for processing. Finally, the spleen filters the blood in search of antigen. Upon the discovery of foreign antigen, all of these tissues react in a similar manner to amass an appropriate and multifaceted immune response. ==Clinical significance== In patients with [[haemochromatosis]] the reticuloendothelial system is a site of iron acumulation. Lymphoma of the reticuloendothelial system is called [[reticuloendotheliosis]]. ==External links== * {{MeshName|Reticuloendothelial+system}} * {{GPnotebook|550502460}} * {{GeorgiaImmunology|1/reticulo}} {{Immune system}} [[Category:Immune system]] {{immunology-stub}} [[ca:Sistema reticuloendotelial]] [[it:Sistema reticoloendoteliale]] [[ja:細網内皮系]] [[pl:Układ fagocytarny]] [[pt:Sistema reticuloendotelial]]