This document discusses the Golgi tendon organ and reflex, as well as the withdrawal reflex. It begins by describing the Golgi tendon organ as stretch receptors located in tendons and musculoaponeurotic junctions. It then explains the pathway and function of the Golgi tendon reflex, which protects muscles from overcontraction via autogenic inhibition. Next, it defines the withdrawal reflex as a polysynaptic reflex that causes limb removal in response to painful stimuli, and describes the neural pathway and variations in withdrawal response, including crossed extensor response and widespread withdrawal. It concludes by discussing the protective function of withdrawal reflexes and comparing physiological and pathological clinical reflexes.

1. GOLGI TENDON
ORGAN
DR NILESH KATE
MBBS,MD
PROFESSOR
ESIC MEDICAL COLLEGE, GULBARGA.
DEPT. OF PHYSIOLOGY
Tuesday, February 4, 2020

2. Golgi tendon reflex
Inverse Stretch reflex
(Disynaptic Reflex)
 Golgi tendon organ
 Pathway & activity of
reflex
 Physiological role
 Clasp knife reflex
Tuesday, February 4, 2020

3. Golgi tendon organ
 Stretch receptors located in
the tendons and
musculoaponeurotic
junction.
 10–15 muscle fibres are
connected in series with one
Golgi tendon organ.
 Each Golgi tendon organ
basically consists of a group
of nerve endings covered by a
capsule of connective tissue
Tuesday, February 4, 2020

4. Golgi tendon organ
 Nerve supply
 Ib-type sensory nerve fibres.
 It ramifies into many
branches. Each branch ends
in the form of a knob.
 The Golgi tendon organs have
neither muscle fibres nor
an efferent innervation.
Tuesday, February 4, 2020

5. Pathway and activity of reflex
 When a muscle contracts, the muscle
tension increases. The Golgi tendon organ
detects the muscle tension.
 Sends impulses through afferent (group Ib)
fibres-- It stimulate the inhibitory
interneurons.
 Release inhibitory mediator GLYCINE,
Tuesday, February 4, 2020

6. Tuesday, February 4, 2020
 which inhibits α-motor neurons and cause
relaxation of the muscle that was originally
contracted.
 At the same time, due to reciprocal
innervation, the antagonistic muscles are
excited. The Golgi tendon reflex, thus,
displays reciprocal innervation but lacks
after discharge and irradiation.

7. Physiological role
 Protective function – from damaging
forceful contraction.
 Regulation of tension during normal muscle
activity - Autogenic inhibition, -- the force
generated when the muscle contracts is
the stimulus for its own relaxation.
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8. Withdrawl reflex
(Polysynaptic reflex)
 Definition
 Flexor reflex, is a cutaneous
reflex which occurs in
response to nociceptive
(pain) stimuli and is
characterized by the removal
of a body part from painful
stimulus.
 Nociceptors located in
free nerve endings of Aδ and
C fibres.
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9. Pathway
 Receptor – afferent fibres
– enter spinal cord – end
on interneurons – some
forms reverberating
circuits (For After
discharge)
 Relay on αmn of ipsilateral
flexors & stimulate, & few
on αmn of ipsilateral
extensors & relax.
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10. Response in withdrawl reflex
 Local sign – one limb response – removal of
one hand
 Flexor response - Response is in the form of
contraction of flexors and inhibition of
extensors leading to flexion of the stimulated
limb.
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11. Response in withdrawl reflex
 Crossed extensor reflex
response - (two-limb
response) extension of
the opposite limb.
 Shifting reaction –
difficult to demonstrate
this response in normal
animals but is easily
demonstrated in spinal
animals
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12. Response in withdrawl reflex
 Widespread withdrawl response. - when
the noxious stimulus is very strong.
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13. Mechanism of varied grades of
withdrawl response
 Irradiation
 Recruitments of
motor units
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14. Characteristics of withdrawl
reflex.
 Long latency
 Response outlasts stimulus
 Patterened response
 Summation
 Occlusion
 Subliminal fringe
 Recruitment
 Irradiation
 Reciprocal inhibition
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15. Function of withdrawl reflex
 Protective reflex
 The flexor response takes the limb away from the source
of irritation.
 Withdrawal reflex is associated with a crossed extensor
reflex, which helps to support the body and is of
physiological significance in the context of regulation of
posture.
 Withdrawal reflex is prepotent, i.e. it pre-empts all other
reflex activities taking place at that time in the involved
spinal cord segment.
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16. Clinical reflexes
 Physiological
reflexes
 Pathological
reflexes.
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17. Physiological reflexes
 Superficial reflexes - receptors on skin
(cutaneous reflexes, e.g. plantar, abdominal,
cremasteric, bulbocavernous) or mucous
membranes (mucous membrane reflexes),
e.g. corneal, conjunctival and palatal reflex.
 Deep reflexes - knee jerk, ankle jerk
 Visceral reflexes - carotid sinus reflex
micturition reflex, oculocardiac reflex
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18. Pathological reflexes.
 Babinski sign,
 Mass reflex,
 Clonus
 Pendular
movements.
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19. THANK
YOU