MeSH

Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.

Year introduced: 1977(1969-1971)

A class of nerve fibers as defined by their nerve sheath arrangement. The AXONS of the unmyelinated nerve fibers are small in diameter and usually several are surrounded by a single MYELIN SHEATH. They conduct low-velocity impulses, and represent the majority of peripheral sensory and autonomic fibers, but are also found in the BRAIN and SPINAL CORD.

Year introduced: 2003

A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. They are fibers of relatively large and varied diameters. Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers (NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves.

Year introduced: 1974 (1972)