Two two main functions of the nervous system are: to collect, process and respond to information in the environment and to co-ordinate the working of different organs and cells in the body.
It is divided into the central nervous system and the peripheral nervous system.
The CNS is made up of the brain and the spinal chord.
The brain is the centre of all consciousawareness.
The outer layer of the brain, the cerebralcortex, is highly developed in humans and is what distinguishes our highermental functions from those of animals.
The spinal chord is an extension of the brain and is responsible for reflex actions.
The spinal chord passes messages from the brain and connects nerves to the PNS.
The PNS transmits messages, via millions of neurons, to and from the nervous system.
The PNS is further sub-divided into the autonomic nervous system (AND) and the somatic nervous system (SNS).
The ANS governs vital functions in the body, such as breathing, heart rate, sexual arousal and stress responses.
The SNS controls muscle movement and receives information from sensory receptors.