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medullary sheath

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noun

Botany. a narrow zone made up of the innermost layer of woody tissue immediately surrounding the pith in plants.
Anatomy. myelin sheath.

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Origin of medullary sheath

First recorded in 1840–50
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

British Dictionary definitions for medullary sheath

medullary sheath

noun

anatomy a myelin layer surrounding and insulating certain nerve fibres
a layer of thick-walled cells surrounding the pith of the stems of some higher plants
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

Medical definitions for medullary sheath

medullary sheath

n.

myelin sheath
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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