nerve fibers

released at the ends of nerve fibers in the somatic and parasympathetic nervous systems

Applied to those nerve fibers which go from the brain to the spinal cord, and so transfer cerebral impulses (centrifugal impressions) outwards.

Applied to those nerve fibers which go from the spinal cord to the brain and so transfer sensations (centripetal impressions) from the exterior inwards.

a bundle of nerve fibers passing from one side to the other of the brain or spinal cord

loss of the myelin covering of some nerve fibers resulting in their impaired function