A group of nerve fibers coursing together as a bundle in the peripheral nervous system. The individual fibers are covered by Schwann cells, many of which contain large amounts of myelin, which makes the nerve appear shiny white. The nerve fibers with their Schwann cell sheaths are held together by connective tissue. In most nerves, some of the fibers are sensory (carrying information to the central nervous system) and some are motor (carrying information from the central nervous system to peripheral glands and muscles). When both sensory and motor fibers are in a nerve, it is called a mixed nerve.