1. Motor Function of spinal cord
Human Reflexes

2. What is a reflex?
Functional unit of CNS, involuntary response to a stimulus
-example/pinprick

3. Reflex Arc -Bell-Magendi law -DIF/ - formed of :
-Sense organ (receptor).
-An afferent neuron.
-One or more synapses (CNS).
-An efferent neuron.
-An effector organ
-Bell-Magendi law

5. Components of reflex arc

6. **- Interneurons (excitatory or inhibitory).
**-Afferent neuron
- Afferent neurons undergo:
1- Divergence WHY?
2- Convergence WHY?
**- Interneurons (excitatory or inhibitory).
- (Two types of circuits formed by inter neurons
(parallel and reverberating circuits).

8. Reverberating circuits 1- Parallel 2-Reverbrating

9. Reverberating circuits
-Function
- In brain and spinal cord
- Respiration&Wakefulness

10. Renshaw cells - located in anterior horn with motor neurons.
-inhibitory (presynaptic inhibition, negative feedback fashion)
& lateral inhibition to nearby neurons.

11. Efferent neuron -
alpha motor neurons
Gamma motor neurons

13. Types of reflexes

14. Stretch reflex

15. Stretch reflex
-Components:-
Receptor :
Afferent
AHC
Efferent
Effector

16. Stretch Reflex/ example Knee jerk

17. Stretch reflex receptor ( Muscle Spindle) Structure of Muscle Spindle:-
Two types of intrafusal fibres: .

18. Muscle Spindle Fibers

19. Innervation of the muscle spindle
1-Sensory Afferent fibres:
2-Efferent fibres to spindle

22. Reaction time/
Central delay/
-Number of synapses

23. Functions of muscle spindle:-

24. Types of responses Component of stretch reflex
1-Dynamic stretch reflex (dynamic or phasic
response)
2- Static stretch reflex( static response

25. Muscle Tone:- Static stretch reflex
Dif/ resistance of muscle to stretch -Stimuli for muscle tone
-Present in ?
-hypotonic or flacidity
-hypertonic,spastic muscle

26. Effect of gamma efferent discharge:-
a- dynamic gamma efferent B-Static gamma efferent

27. alpha-gamma linkage(coactivation)
Muscle can contract by:-
alpha-gamma linkage(coactivation)

28. Reciprocal inhibition IN KNEE JERK/ contraction of EXTENSOR of thigh >>>>>>> relaxation of FLEXORS

30. Physiological Tremor :-.

31. Higher control on gamma efferent discharge :-
1-Cortical areas.
2-Basal ganglia.

32. 3-Brain stem.
Facilitatory
Inhibitory:
4-The cerebellum.

33. Facilitatory supra spinal centers

34. Inhibitory supra spinal centers

35. Factors influence stretch reflex )
Enhances
Inhibits

36. Jendrassik’s Maneuver :

37. The Golgi tendon reflex (inverse stretch reflex- (AUTOGENIC INHIBITION))

38. The Golgi tendon reflex (inverse stretch reflex)

40. Lengthening Reaction:- response of spastic muscle to lengthening
Clonus:- as Ankle clonus

41. Clinical significance of stretch reflex:- -Tendon jerks

42. Centers of some reflexes Clinical significant

43. Centers of some reflexes Clinical significant

44. Withdrawal reflex (flexor reflex)
-Properties of withdrawal R
- crossed extensor reflex

45. Crossed extensor reflex

46. Importance of withdrawal reflex:-
Other examples of polysynaptic reflexes