Mononuclear phagocyte system

Mononuclear phagocyte system

"Reticuloendothelial system" is an older term for the mononuclear phagocyte system. The mononuclear phagocyte system consists primarily of monocytes and macrophages. The spleen is the largest unit of the mononuclear phagocyte system. The monocyte is formed in the bone marrow and transported by the blood; it migrates into the tissues, where it transforms into a histiocyte or a macrophage. Macrophages are diffusely scattered in the connective tissue and in liver (Kupffer cells); spleen and lymph nodes (sinus histiocytes); lungs (alveolar macrophages); and central nervous system (microglia). The half-life of blood monocytes is about 1 day, whereas the life span of tissue macrophages is several months or years. The mononuclear phagocyte system is part of both humoral and cell-mediated immunity. The mononuclear phagocyte system has an important role in defense against microorganisms, including mycobacteria, fungi, bacteria, protozoa, and viruses. Macrophages remove senescent erythrocytes, leukocytes, and megakaryocytes by phagocytosis and digestion.

The mononuclear phagocyte system is a part of the immune system that consists of the phagocytic cells[1] located in reticular connective tissue. The cells are primarily monocytes and macrophages, and they accumulate in lymph nodes and the spleen. The Kupffer cells of the liver and tissue histiocytes are also part of the MPS.

Its functions include:

  • Formation of new red blood cells (RBCs) and white blood cells (WBCs).
  • Destruction of old RBCs and WBCs.
  • Formation of antibody.
  • Formation of plasma proteins.
  • Formation of bile pigments.

"Reticuloendothelial system" is an older term for the mononuclear phagocyte system, but it is used less commonly now, as it is understood that most endothelial cells are not macrophages.[2]

References

  1. ^ MeSH Mononuclear+Phagocyte+System
  2. ^ Inderbir Singh (2006). Textbook of human histology. Jaypee Brothers Publishers. pp. 90–. ISBN 9788180618093. http://books.google.com/books?id=Ej22iANgNkoC&pg=PA90. Retrieved 12 November 2010. 

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Look at other dictionaries:

  • mononuclear phagocyte system — n a system of cells comprising all free and fixed macrophages together with their ancestral cells including monocytes and their precursors in the bone marrow compare RETICULOENDOTHELIAL SYSTEM * * * (MPS) the collection of cells consisting of… …   Medical dictionary

  • mononuclear phagocyte system — noun a widely distributed system of free and fixed macrophages derived from bone marrow • Syn: ↑MPS, ↑system of macrophages • Hypernyms: ↑system • Part Holonyms: ↑reticuloendothelial system, ↑RES …   Useful english dictionary

  • mononuclear phagocyte system — noun Date: 1983 a system of cells comprising all free and fixed phagocytes together with their ancestral cells including monocytes and their precursors in the bone marrow called also reticuloendothelial system …   New Collegiate Dictionary

  • system — systemless, adj. /sis teuhm/, n. 1. an assemblage or combination of things or parts forming a complex or unitary whole: a mountain system; a railroad system. 2. any assemblage or set of correlated members: a system of currency; a system of… …   Universalium

  • system of macrophages — noun a widely distributed system of free and fixed macrophages derived from bone marrow • Syn: ↑mononuclear phagocyte system, ↑MPS • Hypernyms: ↑system • Part Holonyms: ↑reticuloendothelial system, ↑RES …   Useful english dictionary

  • system — 1. [TA] A consistent and complex whole made up of correlated and semiindependent parts. A complex of functionally related anatomic structures. 2. The entire organism seen as a complex organization of parts. 3. Any complex of structures… …   Medical dictionary

  • reticuloendothelial system — n a diffuse system of cells of varying lineage that include esp. the macrophages and the phagocytic endothelial cells lining blood sinuses and that were orig. grouped together because of their supposed phagocytic properties based on their ability …   Medical dictionary

  • reticuloendothelial system — Immunol. the aggregate of the phagocytic cells, including certain cells of the bone marrow, lymphatic system, liver, and spleen, that have reticular and endothelial characteristics and function in the immune system s defense against foreign… …   Universalium

  • reticuloendothelial system — noun Date: circa 1923 mononuclear phagocyte system; broadly the mononuclear phagocyte system plus certain other cells now known to be pinocytic or only weakly phagocytic …   New Collegiate Dictionary

  • reticuloendothelial system — noun a widely distributed system consisting of all the cells able to ingest bacteria or colloidal particles etc, except for certain white blood cells • Syn: ↑RES • Hypernyms: ↑system • Part Holonyms: ↑immune system • Part Meronyms: ↑ …   Useful english dictionary

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