myelin sheath

noun

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

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First Known Use of myelin sheath

1891

in the meaning defined above

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Medical Dictionary

myelin sheath

noun

medical 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

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