reflexes

• Why are reflexes important?

  • Prevents harm
  • Reduces damages
  • They are fast
  • they don’t have to be learned
• What type of reflex is the knee jerk reflex?

  Spinal - neural circuit only goes up to the spinal cord and not the brain
• how does the knee jerk reflex work?

  • Leg tapped below patella (stimulus)
  • Stretches patella tendon
  • Contraction of extensor muscle in top thigh
  • at the same time, relay neurone inhibits motor neurone of flexor muscles- this muscle relaxes
  • Antagonistic action (of the extensor muscle against the flexor muscle) occurs- leg kicks
• How is the knee jerk reflex useful?

  Helps us maintain posture and balance
• What does the absence of the knee jerk reflex imply?

  • Nervous problems
  • Cerebellar disease