Reflex arcs

• Central nervous system - brain and spinal cord
• Peripheral nervous system - The nerves that connect the brain and spinal cord to the rest of the body
• Sensory neurons - carry impulses from the receptors to the CNS
• Motor neurons - carry impulses from the CNS to effectors
• Somatic nervous system - carries nerve impulses to body muscles. Under voluntary control
• Autonomic nervous system - carries nerve impulses to effectors and is under involuntary control
• Reflex arc:

  • Stimulus
  • Receptor
  • Sensory neuron
  • Intermediate neuron
  • Motor neuron
  • Effector
  • Response
• Importance of reflex arcs

  • Involuntary so bypass the brain, leaving it to carry out more complex responses
  • Protect the body from harm, they are innate
  • Few synapses so the neuron pathway is short