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Encyclopedia > Oligodendrocyte
Oligodendrocyte

Oligodendrocyte Image File history File links Download high resolution version (900x800, 214 KB) File links The following pages link to this file: Oligodendrocyte ...

General Information
Tissue type Nervous
Cell type Neuroglia
Location Central nervous system
Role Myelination
Identification Robertson, 1899
Ultrastructure
Soma size 10–20μm
Unique organelles None
Unique feature Myelinating processes

Oligodendrocytes (from Greek literally meaning few tree cells), or oligodendroglia (Greek, few tree glue),[1] are a variety of neuroglia. Their main function is the myelination of axons exclusively in the central nervous system of the higher vertebrates, a function performed by Schwann cells in the peripheral nervous system. A single oligodendrocyte can extend to up to 50 axons, wrapping around approximately 1 mm of each and forming the myelin sheath. Nervous tissue is the fourth major class of vertebrate tissue. ... Neuroglia cells of the brain shown by Golgis method. ... A diagram showing the CNS: 1. ... Myelin is an electrically insulating phospholipid layer that surrounds the axons of many neurons. ... A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the diameter of a droplet of mist or fog. ... Neuroglia cells of the brain shown by Golgis method. ... An axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... A diagram showing the CNS: 1. ... Typical classes Petromyzontidae (lampreys) Placodermi - extinct Chondrichthyes (cartilaginous fish) Acanthodii - extinct Actinopterygii (ray-finned fish) Actinistia (coelacanths) Dipnoi (lungfish) Amphibia (amphibians) Reptilia (reptiles) Aves (birds) Mammalia (mammals) Vertebrata is a subphylum of chordates, specifically, those with backbones or spinal columns. ... Named after the German physiologist Theodor Schwann, Schwann cells are a variety of neuroglia that mainly provide myelin insulation to axons in the peripheral nervous system of jawed vertebrates. ... The peripheral nervous system or PNS, is part of the nervous system, and consists of the nerves and neurons that reside or extend outside the central nervous system (the brain and spinal cord) to serve the limbs and organs, for example. ... An axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... In neuroscience, myelin is an electrically insulating fatty layer that surrounds the axons of many neurons, especially those in the peripheral nervous system. ...

Contents

Origin

Oligodendroglia arise during development from an oligodendrocyte precursor cell which can be identified by its expression of a number of antigens, including the ganglioside GD3 [2], the NG2 chondroitin sulfate proteoglycan [3], and the platelet derived growth factor-alpha receptor subunit PDGF-alphaR [4]. In the rat forebrain the majority of oligodendroglial progenitors arise during late embryogenesis and early postnatal development from cells of the subventricular zones (SVZ) of the lateral ventricles. SVZ cells migrate away from these germinal zones to populate both developing white and gray matter, where they differentiate and mature into myelin-forming oligodendroglia [5]. However, it is not clear whether all oligodendroglial progenitors undergo this sequence of events. It has been suggested that some undergo apoptosis [6] and that some fail to differentiate into oligodendroglia but persist into maturity as adult oligodendroglial progenitors [7]. Oligodendrocyte precursor cells in nervous tissue cells precede oligodendrocytes, and may also be able to generate neurons and astrocytes. ... An antigen is any molecule that is recognized by antibodies. ... Ganglioside is a compound composed of a glycosphingolipid (ceramide and oligosaccharide) with one or more sialic acids (AKA n-acetylneuraminic acid) linked on the sugar chain. ... This article is being considered for deletion in accordance with Wikipedias deletion policy. ... A 250 ml bag of newly collected platelets. ... Platelet-derived growth factor (PDGF) is one of the numerous proteins that regulate cell growth and division. ... Subventricular zone (abbreviated form: SVZ) is a paired brain structure situated throughout the lateral walls of the lateral ventricles. ... The term lateral can refer to: an anatomical definition of direction. ... In anatomy, a ventricle is a part of the body filled with fluid. ... Subventricular zone (abbreviated form: SVZ) is a paired brain structure situated throughout the lateral walls of the lateral ventricles. ... Germinal (1885) is the thirteenth novel in Emile Zolas twenty-volume series Les Rougon-Macquart. ... Myelin is an electrically insulating phospholipid layer that surrounds the axons of many neurons. ... A section of mouse liver showing an apoptotic cell indicated by an arrow // Apoptosis is a process of deliberate life relinquishment by a cell in a multicellular organism. ...


Function

The nervous system of mammals depends crucially on the myelin sheath for insulation as it results in decreased ion leakage and lower capacitance of the cell membrane. There is also an overall increase in impulse speed as saltatory propagation of action potentials occurs at the nodes of Ranvier in between Schwann cells (of the PNS) and oligodendrocytes (of the CNS); furthermore miniaturization occurs, whereby impulse speed of myelinated axons increases linearly with the axon diameter, whereas the impulse speed of unmyelinated cells increases only with the square root of the diameter. The Human Nervous System A human being coordinates its nervous system, the activity of the muscles, monitors the organs, constructs and also stops input from the senses, and initiates actions. ... The cell membrane (also called the plasma membrane, plasmalemma or phospholipid bilayer) is a semipermeable lipid bilayer common to all living cells. ... Saltatory conduction is a means by which action potentials are transmitted along myelinated nerve fibers. ... A. A schematic view of an idealized action potential illustrates its various phases as the action potential passes a point on a cell membrane. ... This article is about anatomy; for the musical group see Nodes of Ranvier (band) Nodes of Ranvier are regularly spaced gaps in the myelin sheath around an axon or nerve fiber. ... Schwann cells are a variety of neuroglia that wrap around axons in the peripheral nervous system, forming the myelin sheath. ... The peripheral nervous system or PNS, is part of the nervous system, and consists of the nerves and neurons that reside or extend outside the central nervous system (the brain and spinal cord) to serve the limbs and organs, for example. ... A diagram showing the CNS: 1. ...


As part of the nervous system they are closely related to nerve cells and like all other glial cells the oligodendrocytes have a supporting role towards neurons. They are intimately involved in signal propagation, providing the same functionality as the insulation on a household electrical wire.


Satellite oligodendrocytes are functionally distinct from most oligodendrocytes. They are not attached to neurons and therefore do not serve an insulating role. They remain close to neurons and regulate the extracellular fluid.[8]


Pathology

Diseases that result in injury to the oligodendroglial cells include demyelinating diseases such as multiple sclerosis and leukodystrophies. Oligodendrocyte dysfunction has also been implicated in the pathophysiology of schizophrenia and bipolar disorder [9].Oligodendroglia are also susceptible to infection by the JC virus, which causes progressive multifocal leukoencephalopathy (PML), a condition which specifically affects white matter, typically in immunocompromised patients. Tumors of oligodendroglia are called oligodendrogliomas. Leukodystrophy refers to progressive degeneration of the white matter of the brain due to imperfect growth or development of the myelin sheath, the fatty covering that acts as an insulator around nerve fiber. ... The JC virus (JCV) is a type of human polyomavirus (formerly known as papovavirus) and is genetically similar to BK virus and SV40. ... Progressive multifocal leukoencephalopathy (PML), also known as progressive multifocal leukoencephalitis, is a rare and usually fatal viral disease that is characterized by progressive damage (-pathy) or inflammation (-itis) of the white matter (leuko-) of the brain (-encephalo-) at multiple locations (multifocal). ... Immunosuppression is the medical suppression of the immune system. ... Tumor or tumour literally means swelling, and is sometimes still used with that meaning. ...


Notes

  1. ^ (Ragheb 1999, p. 14).
  2. ^ Curtis et al., 1988; LeVine and Goldman, 1988; Hardy and Reynolds, 1991; Levine et al., 1993
  3. ^ Levine et al., 1993
  4. ^ Pringle et al., 1992
  5. ^ Hardy and Reynolds, 1991; Levison and Goldman, 1993
  6. ^ Barres et al., 1992
  7. ^ Wren et al., 1992
  8. ^ Baumann and Pham-Dinh, 2001
  9. ^ Tkachev et al., 2003

References

  • Baumann, Nicole & Danielle Pham-Dinh (2001), "Biology of Oligodendrocyte and Myelin in the Mammalian Central Nervous System", Physiological Reviews 18(2): 871–927 [link accessed 2007-07-13]
  • Ragheb, Fadi (1999), The M3 Muscarinic Acetylcholine Receptor Mediates p42mapk Activation and c-fos mRNA Expression in Oligodendrocyte Progenitors, Ottawa: National Library of Canada [link accessed 2006-03-07]
  • Raine, C.S. (1991). Oligodendrocytes and central nervous system myelin. In Textbook of Neuropathology, second edition, R.L. Davis and D.M. Robertson, eds. (Baltimore, Maryland: Williams and Wilkins), pp. 115–141.
  • Tkachev D, Mimmack ML, Ryan MM, Wayland M, Freeman T, Jones PB, Starkey M, Webster MJ, Yolken RH, Bahn S. (2003). Oligodendrocyte dysfunction in schizophrenia and bipolar disorder. Lancet. 2003 Sep 6;362(9386):798-805.PMID: 13678875

  Results from FactBites:
 
Oligodendrocyte - Wikipedia, the free encyclopedia (256 words)
A single oligodendrocyte can extend to up to 50 axons, wrapping around approximately 1 mm of each and forming the myelin sheath.
Oligodendrocytes, as well as other macroglial cells (astrocytes and ependymal cells), are derived from neuroectoderm.
As part of the nervous system they are very closely related to nerve cells and like all other glial cells the oligodendrocytes have a supporting role towards neurons and are intimately involved in signal propagation, providing the same functionality as the insulation on a household electrical wire.
oligodendrocyte - multiple sclerosis encyclopaedia (495 words)
Oligodendrocytes, also known as oligodendroglia, belong to a class of cells in the central nervous system known as glial cells.
Oligodendrocytes are responsible for producing a fatty protein, called myelin, which insulates axons, the long extensions of nerve cells (neurons).
Oligodendrocytes mature from stem cells called O-2A progenitor cells which can be purified and grown in large numbers in cell cultures outside the human body.
  More results at FactBites »

 
 

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