<P> A nerve is an enclosed, cable - like bundle of axons (nerve fibers, the long and slender projections of neurons) in the peripheral nervous system . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons to peripheral organs . </P> <P> In the central nervous system, the analogous structures are known as tracts . Neurons are sometimes called nerve cells, though this term is potentially misleading since many neurons do not form nerves, and nerves also include non-neuronal Schwann cells that coat the axons in myelin . </P> <P> Each nerve is a cordlike structure containing bundles of axons . Within a nerve, each axon is surrounded by a layer of connective tissue called the endoneurium . The axons are bundled together into groups called fascicles, and each fascicle is wrapped in a layer of connective tissue called the perineurium . Finally, the entire nerve is wrapped in a layer of connective tissue called the epineurium . </P> <P> Nerves are categorized into three groups based on the direction that signals are conducted: </P>

Fascicles within spinal nerves are surrounded by fibers of the