Each nerve is supplied with tiny blood vessels for nourishment. Some nerves carry information in one direction only, while others are two-way. One-way nerves are described as sensory nerves when they carry information to the brain, or motor nerves, when they carry signals from the brain. Both of these types of nerves are found throughout the body. The two-way nerves are called mixed nerves and they are mostly found in the spinal cord.
Nerve cells have to be able to respond to stimulation and to carry signals through the body.
Once a nerve has been activated, it carries an electrical signal along its length. The signal must then be passed on to the next nerve cell. The ends of nerve cells are separated from each other by tiny gaps, called synapses. When the signal arrives at the nerve ending, chemicals called neurotransmitters are released from the cell. Once released, the chemicals travel across the synapse and are picked up by the next nerve cell, that is, in turn, stimulated to make a new electrical signal.