Nerves provide a pathway for electrochemical impulses to transfer between the brain and other parts of the body. A nerve is an enclosed, cable-like structure that contains bundles of axons. An axon conducts electrochemical impulses and transmits them through projections to other neuron cells in nerves, muscles or organs. Through this process, the brain is able to communicate to other areas of the body, allowing processes such as muscle movement or breathing to occur.
There are three main types of neurons: sensory neurons, motor neurons and relay neurons. Relay neurons carry electrochemical impulses from one area of the central nervous system to another, such as the thalamus transmitting information to the brain stem. Sensory neurons convert outside stimuli into electrochemical signals and transmit them to nerves, the spinal cord and then to the brain, allowing for sensations such as sound, taste, sight and touch.
Motor neurons transmit electrochemical signals from the brain to an area of the body that is meant to respond to the signal. The targeted area for the signal can be a muscle, organ or gland. Individuals who suffer from neurological diseases, such as Parkinson's disease or multiple sclerosis, have neural damage that affects the way nerve signals are transmitted in their bodies, often leading to symptoms such as loss of muscle control.