Form major portion of the white matter of the brain and spinal cord and all nerves. Most fibers in peripheral nerves are myelinated.

Fibers that extend from the body of a nerve cell that transmit electrical pulses as part of the information handling in the nervous system. - A bundle of nerve fibers (axons). The fibers are either afferent - leading towards the brain and serving in the perception of sensory stimuli of the skin, joints, muscles, and inner organs; or efferent - leading away from the brain and mediating contractions and relaxsations of muscles or organs.

Slender processes of neurons, especially the prolonged axons that conduct nerve impulses.

Long extensions of nerve cells, also called axons.

Pathways for impulses between nerve centers and body parts.

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.