Reflex actions

• Reflexes are automatic responses to certain stimuli
• They are faster than conscious actions and therefore can prevent injury
• The path taken by the information in a reflex is called a reflex arc
• The pathway an electrical impulse takes in a reflex action is called the reflex arc.
• Path of reflex arc

  • Stimulus
  • Receptor
  • Sensory neurone
  • Synapse
  • Relay neurone
  • Motor neurone
  • Effector
  • Response
• The gaps between neurons are called synapses.
• How messages are transmitted across a synapse:

  ● Electrical impulse arrives at the end of a neurone

  ● Chemicals called neurotransmitter are released into the synapse.

  ● The neurotransmitter diffuses across the synapse.

  ● This triggers a new electrical impulse in the second neurone