Anatomy (Structure) of a Nerve
Nerves are the organs that make up the peripheral nervous system (PNS). They serve as information pipelines that allow the brain and spinal cord to communicate with other tissues and organs.
Inside the nerves are the axon processes of sensory and motor neurons (nerve cells).
The axons are grouped together into bundles called fascicles (fasciculi), which extend the length of the nerve.
Surrounding and holding together each fascicle is a sheath of perineurium
This covering is concentrically laminated and is composed of flattened perineurial cells, basement membrane, and collagen fibers.
Inside the fasicles, neurons and blood vessels are held in place by a loose connective (areolar) tissue referred to as endoneurium.
Epineurium, a layer of dense connective tissue, covers and holds together the outer surface of nerves.
Arteries and veins are located between the fascicles. Branches of these vessels enter the fascicles and supply the neurons with nutrients and gases.