myelin sheath

https://doi.org/10.1351/goldbook.11899
Concentric layers of myelin surrounding the axons of some neurons.
Note: The myelin sheath increases the conduction velocity of electrical impulses.
Source:
PAC, 2015, 87, 841. (IUPAC Glossary of terms used in neurotoxicology (IUPAC Recommendations 2015)) on page 884 [Terms] [Paper]