1. Reflexes Prof. Vajira Weerasinghe Dept of Physiology

3. What is a reflex? Stimulus Effector organ Response Central connections Efferent nerve Afferent nerve Receptor

7. Extrafusal fibre Intrafusal fibre

8. Contractile areas Stretch receptor

9. Nerve supply Sensory to intrafusal fibre: Ia afferent II afferent Motor: to extrafusal fibre  motor neuron to intrafusal fibre  motor neuron .

10. Ia afferent nerve  motor neuron one synapse muscle stretch muscle contraction Stretch reflex

12. Stretch Reflex

13. Stretch Reflex - Knee Jerk

15. Ia afferent fibre II afferent fibre nuclear bag fibre nuclear chain fibre  motor neuron  motor neuron

18.  motor neuron  motor neuron  motor neuron

20. at rest muscle stretched active  motor neuron Ia Ia  Ia afferents are stimulated stretch reflex is initiated .

29. Undue stretch Golgi tendon organ muscle relaxation Inverse stretch reflex  motor neuron Ib afferent nerve inhibitory interneuron

30. Undue stretch Golgi tendon organ muscle relaxation Inverse stretch reflex  motor neuron Ib afferent nerve inhibitory interneuron

31. Inverse Stretch Reflex

36. Withdrawal Reflex

37. muscle contraction Withdrawal reflex cutaneous receptors polysynaptic

38. muscle contraction Withdrawal reflex cutaneous receptors

39. Withdrawal Reflex

41. Reciprocal Innervation

42. Withdrawal Reflex Flexor & Crossed extensor reflex

43. Withdrawal Reflex

48. positive Babinski sign