The nervous system

• 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 conscious awareness.
• The outer layer of the brain, the cerebral cortex, is highly developed in humans and is what distinguishes our higher mental 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.