Term Name:	myelin sheath
Synonyms:	astrocyte sheath, oligodendrocyte myelin sheath, Schwann cell myelin sheath
Definition:	An electrically insulating fatty layer that surrounds the axons of many neurons. It is an outgrowth of glial cells: Schwann cells supply the myelin for peripheral neurons while oligodendrocytes supply it to those of the central nervous system.
Ontology:	GO: Cellular Component [GO:0043209]    QuickGO    AmiGO