Definition of myelin sheath
: the insulating covering that surrounds an axon with multiple spiral layers of myelin, that is discontinuous at the nodes of Ranvier, and that increases the speed at which a nerve impulse can travel along an axon
— called also medullary sheath
Examples of myelin sheath in a Sentence
Recent Examples on the Web
The mutations may damage the nerves or damage the myelin sheath, the protective coating that surrounds the nerve.
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Korin Miller, Health.com, 28 Sep. 2021
Without the myelin sheath, signals that go through a nerve are slowed or lost, which causes the nerve to malfunction.
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Aarti Sarwal, The Conversation, 7 July 2020
Both widening of the nodal gap and thinning of the myelin sheath slow the speed of impulse transmission.
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R. Douglas Fields, Scientific American, 12 Mar. 2020
When the protective covering on nerve fibers (also known as the myelin sheath) is worn away from this damage, the nerves don't work how they're supposed to, causing communication errors between the brain and body.
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Amy Marturana Winderl, SELF, 1 Mar. 2020
In another study, Rathmell and colleagues added dichloroacetate, which suppresses glycolysis, to the drinking water of mice that have a condition that mimics multiple sclerosis, in which the immune system attacks nerves' insulating myelin sheath.
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Mitch Leslie, Science | AAAS, 29 Mar. 2018
The brain is almost 60 percent fat, and each neuron requires a fatty myelin sheath to transmit impulses.
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Sophie Weiner, Popular Mechanics, 15 Dec. 2017
See MoreThese example sentences are selected automatically from various online news sources to reflect current usage of the word 'myelin sheath.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
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“Myelin sheath.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/myelin%20sheath. Accessed 24 Jan. 2022.
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The first known use of myelin sheath was in 1891
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