The nervous system is the main control center for the body. It functions to initiate and coordinate movement, interpret senses and monitor organs. The nervous system is divided into two categories: the central nervous system (CNS) and the peripheral nervous system (PNS). The brain and spinal cord make up the central nervous system and receive and process information from the rest of the body’s nerves, which make up the peripheral nervous system.
Communication throughout the nervous system is based on transmission of electrochemical signals, which allows sharing of information between the outside world, the body, and the brain. These messages are passed along nerve cells called neurons. Neurons are long thin cells that can reach more than 3 feet. They are stimulated by heat, cold, touch, sound vibrations, and other messages which generate an electrical impulse. This impulse travels the length of the cells and chemically passes between cells to its final destination. Neurons are sometimes wrapped in a myelin sheath which helps to facilitate signal transmission along the cell.
Peripheral nerves are thin threads of axons grouped together like bundles of wires in a cable. These bundles are called fascicle and are wrapped in connective tissue, called epineurium, to make a nerve. Peripheral nerves provide communication between the brain and organs. Sensory nerves carry messages that signal touch, vision, hearing, taste, and smell. Motor nerves carry messages that control the body’s movement.
Injury to the peripheral nerves can cause interruption of the signals between the brain and the target organs. If unrepaired, there can be permanent loss of motor and/or sensory function. People suffering from these injuries may be robbed of the ability to smile, taste, feel with their fingers, or walk.