What Are Nerve Fibers?
Nerve fibers, also known as axons, are very thin transmission lines that run from each nerve cell in the body to receptors in the skin, muscles, and internal organs. They are the main information lines of the central nervous system. Though nerve fibers are microscopic in diameter, they can be very long. One of the longest fibers runs from the sciatic nerve at tip of the spine down the leg to the tip of the big toe. There are three main classes of nerve fibers: A, B, and C. Class A fibers transmit impulses related to muscle, tendon, and articular movement and situation. These fibers are myelinated, or sheathed in an electrically insulated material. Class B nerve fibers transmit autonomic or involuntary impulses and are also myelinated. Class C nerve fibers relay pain and temperature impulses and are not myelinated.
