Nerves

• The nervous system is made up of the CNS (Central Nervous System) and the peripheral nervous system
• The nervous system is a means of gathering information about, and responding to, changes in the environment either inside or outside the body
• The nervous system is made up of receptors which respond to stimuli and pass on information about them
• The central nervous system (CNS) co-ordinates the information and responds by sending signals to the effectors, which bring about a response
• Electrical signals are carried around the body along neurones
• Example of nervous system response

  Stimulus > receptor > CNS > effector > response
• Light intensity > eye > brain > eye muscles receive information > eye muscles make pupil smaller