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myelin

[mahy-uh-lin] /ˈmaɪ ə lɪn/
noun, Biology
1.
a soft, white, fatty material in the membrane of Schwann cells and certain neuroglial cells: the substance of the myelin sheath.
Also, myeline
[mahy-uh-leen] /ˈmaɪ əˌlin/ (Show IPA)
.
Origin
1865-1870
1865-70; myel- + -in2
Related forms
myelinic, adjective
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Examples from the web for myelin
  • In both cases, the yellow-green color corresponds to newly-grown myelin.
  • As myelin degrades, the fibers cannot conduct electrical impulses.
  • Without this sheath, made of a substance called myelin, nerve cells eventually die.
  • The illness is believed to result from impaired signaling between neurons in the brain caused by a reduction in myelin.
  • White matter could respond similarly, ramping up myelin production and raising the speed limit along certain routes.
  • White matter contains the protein myelin, which coats neurons' spindly axons as they reach toward other areas of the brain.
  • Surviving neurons often lose myelin, the insulation needed for reliable and quick signal transmission.
  • The tissue is white because many axons are coated with tightly wrapped layers of electrical insulation called myelin.
  • My diagnosis is that the myelin sheathing around my nerves was not being repaired because of a lack of cholesterol.
  • The body needs this substance to make myelin, the material that surrounds and protects nerve fibers.
British Dictionary definitions for myelin

myelin

/ˈmaɪɪlɪn/
noun
1.
a white tissue forming an insulating sheath (myelin sheath) around certain nerve fibres. Damage to the myelin sheath causes neurological disease, as in multiple sclerosis
Derived Forms
myelinic, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for myelin
n.

also myeline, "soft material found in nerve tissues," 1867, from German Myelin (1854), from Greek myelos "marrow; the brain, innermost part," of unknown origin.

Online Etymology Dictionary, © 2010 Douglas Harper
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myelin in Medicine

myelin my·e·lin (mī'ə-lĭn) or my·e·line (-lĭn, -lēn')
n.

  1. A white fatty material composed chiefly of alternating layers of lipids and lipoproteins that encloses the axons of myelinated nerve fibers.

  2. Droplets of lipid formed during autolysis and postmortem decomposition.


my'e·lin'ic adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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myelin in Science
myelin
  (mī'ə-lĭn)   
A whitish, fatty substance that forms a sheath around many vertebrate nerve fibers. Myelin insulates the nerves and permits the rapid transmission of nerve impulses. The white matter of the brain is composed of nerve fibers covered in myelin.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Encyclopedia Article for myelin

white, insulating sheath composed of fatty materials, protein, and water on the axon of many nerve fibres. The myelin sheath is deposited by Schwann cells in layers surrounding the nerve fibres of the central and peripheral nervous systems of many organisms. The sheath is interrupted at intervals by gaps called nodes of Ranvier; this structure speeds nerve conduction, as impulses jump from node to node in a process known as saltatory conduction.

Learn more about myelin with a free trial on Britannica.com
Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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