Reflex arc

• CNS has a fast & automatic reaction.

  Without thinking
• Receptor cells detect change, and create an electrical impulse up the sensory neurone to the spinal cord which is attached to the brain
• The impulse is then travelled down to the relay neurone which will need to pass it to the motor neurone
• to get to the motor neurone , there is a synapse (gap) between both neurones
• What is between the synapse?

  Neurotransmitters
• Order of neurones?


  Sensory

  Relay

  Motor
• What do the neurotransmitters in the synapse?


  They diffuse across the synapse to the motor neurone
• These neurotransmitters create a new electrical impulse that travels down the motor neurone to the effector causing the body to react