The Nervous System

• What does the nervous system do?

  Detects and reacts to stimuli in order to survive
• What are the four parts of the nervous system?

  • CNS
  • Effectors
  • Motor neurones
  • Sensory neurones
• What is the sequence of events which describes how the nervous system works?

  Stimuli --> Receptor --> Coordinator --> Effector --> Response
• How is a response carried out by the nervous system?

  • Stimulus is converted into electrical impulse by receptors
  • The impulse passes along the sensory neurones to the CNS
  • The CNS coordinates a response and an electrical impulse is sent along the motor neurones to the effectors where the response is carried outors where the response is carried outors where the response is carried outors where the response is carried out
• What connects neurones together?

  Synapses - Nerve signal transferred by chemicals which diffuse across the gap
• What are reflexes?

  Automatic, rapid and unconscious responses to stimuli.
• Why are reflexes important?

  They aid survival and prevent harm to the body.
• Name the process of the reflex arc:

  • Stimulus is detected by the receptor
  • Electrical impulse passes along the sensory neurone to the spinal cord
  • Chemicals diffuse through synapse between relay and sensory neurone and stimulate a new impulse which passes along the relay neurone
  • the same process occurs between the synapse of the relay and motor neurone
  • At the effector, an apporiate response is carried out