14.6 Reflexes

• Reflexes help perverse homeostasis by enabling to respond rapidly to changes in internal/external environment
• A reflex is an immediate involuntary motor response to a specific stimulus 
• The neural wiring of a single reflex is called a reflex arc
• Reflex arc begins at receptors, ends at peripheral effector
• Steps of the reflex arc

  • One: Stimulation and activation of receptor 
  • Two: Activation of a sensory neuron 
  • Three: Information processing the central nervous system 
  • Four: Activation of a motor neuron 
  • Five: Response by effector
• Classification of Reflexes. Compares four different criteria used to classify reflexes: 

  • Development 
  • Response 
  • Complexity of circuit 
  • Processing site 
• Classification of Reflexes. In simplest reflex arc, a monosynaptic reflex, a sensory neuron synapses directly on motor neuron
• Classification of Reflexes. Polysynaptic reflex is more complex and has a longer delay between the stimulus and response
• Classification of Reflexes. Spinal Reflexes. Best known spinal reflex is the stretch reflex
• Classification of Reflexes. Spinal Reflexes. Stretch reflex, simple monosynaptic reflex providing automatic regulation of skeletal muscle length
• Classification of Reflexes. Spinal Reflexes. Most familiar stretch reflex is patellar reflex
• Classification of Reflexes. Spinal Reflexes. Postural reflex, reflex that maintains normal upright posture
• Classification of Reflexes. Higher Centers and Integration of Reflexes. Reflexive motor activity occur automatically without instructions