medullary sheath
- 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. 2018
medullary sheath
- 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
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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
medullary sheath
- myelin sheath
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The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.