Receptors:-
Definition-receptors are the modified structures of sensory nerve ending which can convert different form of energy stimulated inrto electrical energy
Classification:
1)based on source of stimulus.
-based on type stimulus
Mechanoreceptors-pacinian receptor -pressure
2)Chemoreceptors-olfactory receptor
3)thermoreceptor-ruffini's end(hot),end bulb krause-cold
4)nocise recepters -pain.
5)photoreceptors-light -rods and cone cell
6)PROPRIOCEPTION-MUSCLE SPINDLE,GOLGI TENDON.
-BASED ON ADAPTATION
a)fast adapting receptor-olfactory and taste recepters
b)slow adapting receptors-golgi tendon,muscle spindle
c)non adapting receptors-pain recepters.
Properties:-
a)specificity-each receptor requires specific stimulus to show the response.
Eg: rods and cones in retina they get stimulated by light.
b)adaptation:-response declines when stimulus given repeatedly
Eg:-olfactory receptors,touch receptors.
c)law of projection:-anywhere along the sensory pathway stimulates in given response is shown
Eg-amputated limb
d)two point dscrimination and localisation.-
i)compass asthenia meter-instrument.
finger tip -distance in minimum number of receptors are more
Back tip-distance is maximum -no of receptors are less.
e)receptor potential:-action potential develops at receptor end -non propagatory.
Does Not follow all or none law.
f)weber fechner's law:-sensation felt is directly proportional to intensity of stimulus.
Sensation felt is two times increased.intensity of stimulus 10 times increased.
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Reflex action
Definition:-sudden involuntary action to the external stimuli.
Parts of reflex action.:-
1)receptor: stimulus is received by receptors.
2)afferent neuron\sensory neuron:-carries sensation
2)center/spinal cord.
4)efferent neuron/motor neuron.
5)effector(muscles contraction),gland.
Classification:-
1)based on the number of synapse
2)Based on development.
i)acquired reflexes -knitting
ii)inborn reflexes-sucking.
3)based on clinical classification.
i)deep reflex:-also called as tendon jerk reflex
Eg:-bicep jerk,tricep jerk.
ii)superficial reflex:-corneal reflex
iii)pathological reflex-Babinski’s sign
iiii)Visceral reflex-micturition reflex.
4)based on physiological reflex.
i)extensor reflex-to maintain posture.
ii)flexor reflex-withdrawal reflex
5)stretch reflex.
i)inverse stretch reflex-The Golgi tendon reflex (also called inverse stretch reflex, autogenic inhibition, tendon reflex) is an inhibitory effect on the muscle resulting from the muscle tension stimulating Golgi tendon organs (GTO) of the muscle, and hence it is self-induced.
ii)crossed extensor reflex
-to maintain balance during noxious stimulus.
-same limb goes to flexion.
-opposite limb goes to extension.
Properties of reflex:-
i)delay
II)one way conduction.
iii)summation.
iv)occlusion.
v)habituation and sensitization.
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