medullary sheath


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medullary sheath

medullary sheath

n
1. (Anatomy) anatomy a myelin layer surrounding and insulating certain nerve fibres
2. (Botany) a layer of thick-walled cells surrounding the pith of the stems of some higher plants

med′ullary sheath′


n.
1. a narrow zone made up of the innermost layer of woody tissue immediately surrounding the pith in plants.
[1840–50]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.medullary sheath - a layer of myelin encasing (and insulating) the axons of medullated nerve fibersmedullary sheath - a layer of myelin encasing (and insulating) the axons of medullated nerve fibers
sheath, case - an enveloping structure or covering enclosing an animal or plant organ or part
axolemma - outer membrane covering an axon
medullated nerve fiber, myelinated nerve fiber - a nerve fiber encased in a sheath of myelin
nodes of Ranvier, Ranvier's nodes - small gaps in the myelin sheath of medullated axons
oligodendria, oligodendroglia - tissue consisting of glial cells with sheetlike processes that form the myelin sheath of nerve fibers
medulla, myelin, myeline - a white fatty substance that forms a medullary sheath around the axis cylinder of some nerve fibers