Inverse Stretch Reflex

INVERSE STRETCH REFLEX

Q. 1

Regarding Golgi tendon organ true is

 A

Senses dynamic length of muscle

 B

Involved in reciprocal innervation

 C

a-motor neuron stimulation

 D

Senses muscle tension

Q. 1

Regarding Golgi tendon organ true is

 A

Senses dynamic length of muscle

 B

Involved in reciprocal innervation

 C

a-motor neuron stimulation

 D

Senses muscle tension

Ans. D

Explanation:

senses muscle tension[Ref: Guvton’s Physiology 11/e,p 674-680; Ganong 22/e, p 130-134; Repeat front Nov 06 Q. 16]

  • The Golgi Tendon organ is an encapsulated sensory receptor through which muscle tendon fibres pass and it is stimulated by increased tension in the connecting muscle. So basically detects muscle tension as reflected by the tension in itself. Whereas muscle spindle (other sensory receptor) detects muscle length and changes in muscle length.

Golgi tendon organ –> detects muscle tension

Muscle spindle –> detects muscle length and changes in muscle length.

  • Muscle spindle and Golgi tendon organ both receptors are important component of intrinsic muscle control.
  • Muscle spindle acts through muscle stretch reflex. Whenever a muscle is stretched suddenly, excitation of the spindles cause reflex contraction of the large skeletal muscle fibres of stretched muscle thus maintain the muscle length & stabilise body positions during tense motor action. Stretch reflex also prevents oscillations & jerkiness of body movements.
  • However when the tension in muscle becomes great enough, contraction suddenly ceases and the muscle relaxes. This relaxation in response to strong stretch is called the inverse stretch reflex, autogenic inhibition or lengthening reaction. The receptor for this reflex is in the Golgi tendon organ. This is a protective mechanism to prevent tearing of the muscle or avulsion of the tendon from its attaclunent to the bone.
  • Reciprocal innervation is the phenomenon in which relaxation of antagonistic muscles occur when a stretch reflex occurs and Golgi bottle neurons (inhibitory interneuron) are involved in this phenomenon.
  • a-motor neurons are anterior motor neuron (located in ant. horn of spinal cord) and when stimulated cause contraction of muscle fibres. Golgi tendon organs when stimulated cause a -motor neuron inhibiton (Muscle spindle stimulation causes a-motor neuron excitation)

Q. 2 The inverse stretch reflex is due 
 A Trail fibre ending
 B Golgi tendon
 C Tail fibre ending
 D Muscle spindle
Q. 2 The inverse stretch reflex is due 
 A Trail fibre ending
 B Golgi tendon
 C Tail fibre ending
 D Muscle spindle
Ans. B

Explanation:

Golgi tendon


Q. 3

All of the following are TRUE about inverse stretch reflex, EXCEPT:

 A

Golgi tendon is the receptor organ

 B

Autogenic excitatory negative feedback lengthening reaction

 C

Protects against muscle tear

 D

Sudden relaxation of muscle to high tension

Q. 3

All of the following are TRUE about inverse stretch reflex, EXCEPT:

 A

Golgi tendon is the receptor organ

 B

Autogenic excitatory negative feedback lengthening reaction

 C

Protects against muscle tear

 D

Sudden relaxation of muscle to high tension

Ans. B

Explanation:

Inverse stretch reflex or autogenic inhibiton is one in which when the tension in the muscle becomes very high there is sudden relaxation of the muscle. This inhibitory negative feedback lengthening reaction protects tearing of muscle or avulsion of tendon. Golgi tendon organ detects the muscle tension and is responsible for this reflex.

Ref: Ganong’s, Review of Medical physiology, 22 Edition, Page 134.


Q. 4

When the tension becomes great enough, contraction suddenly ceases and the muscle relaxes, this phenomenon is known as:

 A

Reciprocal innervations

 B

Autocrine innervation

 C

Autogenic inhibition

 D

Converse stretch reflex

Q. 4

When the tension becomes great enough, contraction suddenly ceases and the muscle relaxes, this phenomenon is known as:

 A

Reciprocal innervations

 B

Autocrine innervation

 C

Autogenic inhibition

 D

Converse stretch reflex

Ans. C

Explanation:

Up to a point, the harder a muscle is stretched, the stronger is the reflex contraction. However, when the tension becomes great enough, contraction suddenly ceases and the muscle relaxes. This relaxation in response to strong stretch is called the inverse stretch reflex or autogenic inhibition.

Ref: Ganong’s Review of Medical Physiology 23rd edition, Chapter 9.


Q. 5

Which among the following is the receptor for inverse stretch reflex?

 A

Trail fibre ending

 B

Golgi tendon

 C

Tail fibre ending

 D

Muscle spindle

Q. 5

Which among the following is the receptor for inverse stretch reflex?

 A

Trail fibre ending

 B

Golgi tendon

 C

Tail fibre ending

 D

Muscle spindle

Ans. B

Explanation:

Up to a point, the harder a muscle is stretched, the stronger is the reflex contraction. However, when the tension becomes great enough, contraction suddenly ceases and the muscle relaxes. This relaxation in response to strong stretch is called the inverse stretch reflex. The receptor for the inverse stretch reflex is in the Golgi tendon organ. There are 3–25 muscle fibers per tendon organ.

 
Ref: (2012). Chapter 12. Reflex and Voluntary Control of Posture & Movement. InBarrett K.E., Boitano S, Barman S.M., Brooks H.L. (Eds), Ganong’s Review of Medical Physiology, 24e.

Q. 6

The inverse stretch reflex is mediated by:

 A

Trail fibre ending

 B

Golgi tendon

 C

Tail fibre ending

 D

Muscle spindle

Q. 6

The inverse stretch reflex is mediated by:

 A

Trail fibre ending

 B

Golgi tendon

 C

Tail fibre ending

 D

Muscle spindle

Ans. B

Explanation:

Inverse stretch reflex is one in which when the tension in the muscle becomes very high there is sudden relaxation of the muscle. This inhibitory negative feedback lengthening reaction protects tearing of muscle or avulsion of tendon. Golgi tendon organ detects the muscle tension and is responsible for this reflex.

  • Afferent limb: Golgi tendon organ and 1b afferents
  • CNS unit: inhibitory interneuron
  • Efferent limb: alpha motor neuron and homonymous muscle
Inverse stretch reflex or autogenic inhibiton: is one in which when the tension in the muscle becomes very high there is sudden relaxation of the muscle. This inhibitory negative feedback lengthening reaction protects tearing of muscle or avulsion of tendon. Golgi tendon organ detects the muscle tension and is responsible for this reflex.
 
Stretch reflex: When a muscle is stretched there is reflex contraction of the stretched muscle. Reflex is initiated by the stretch of the muscle and the response is contraction of the muscle that is being stretched. Muscle spindle is the sense organ for this reflex and the impulse are carried by the fast sensory fibres to the CNS.
 
Ref: Ganong’s, Review of Medical physiology, 22 Edition, Page 134.

Q. 7

The average number of muscle fibres attached to one golgi tendon organ are –

 A

1-3

 B

5-10

 C

10-15

 D

15-75

Q. 7

The average number of muscle fibres attached to one golgi tendon organ are –

 A

1-3

 B

5-10

 C

10-15

 D

15-75

Ans. C

Explanation:

C i.e. 10- 15


Q. 8

Regarding Golgi tendon organ true is

 A

Senses dynamic length of muscle

 B

Involved in reciprocal innervation

 C

a-motor neuron stimulation

 D

Senses muscle tension

Q. 8

Regarding Golgi tendon organ true is

 A

Senses dynamic length of muscle

 B

Involved in reciprocal innervation

 C

a-motor neuron stimulation

 D

Senses muscle tension

Ans. D

Explanation:

D i.e. Senses muscle tension


Q. 9

True statement about golgi tendon organ is

 A

High threshold

 B

Dynamic response only

 C

Detects length change

 D

3-25 muscle fibers.

Q. 9

True statement about golgi tendon organ is

 A

High threshold

 B

Dynamic response only

 C

Detects length change

 D

3-25 muscle fibers.

Ans. D

Explanation:

D i.e. 3-25 muscle fibers.


Q. 10

Golgi tendon organ true is A/E

 A

Static & dynamic response

 B

Activated by both stretch and contraction of muscle

 C

Responsible for stretch reflex

 D

Transmit to Ib fibers

Q. 10

Golgi tendon organ true is A/E

 A

Static & dynamic response

 B

Activated by both stretch and contraction of muscle

 C

Responsible for stretch reflex

 D

Transmit to Ib fibers

Ans. C

Explanation:

C i.e. Responsible for stretch reflex


Q. 11

Tendon organ , correct is A/E

 A

Ramified nobby nerve endings

 B

Regulates tension

 C

Weak stretch activates reflex

 D

Myelinated Ib fibers

Q. 11

Tendon organ , correct is A/E

 A

Ramified nobby nerve endings

 B

Regulates tension

 C

Weak stretch activates reflex

 D

Myelinated Ib fibers

Ans. C

Explanation:

C i.e. Weak stretch activates reflex


Q. 12

Autogenic inhibition is function of

 A

Intrafusal fiber

 B

Extrafusal fiber

 C

Golgi tendon organ

 D

Muscle spindle

Q. 12

Autogenic inhibition is function of

 A

Intrafusal fiber

 B

Extrafusal fiber

 C

Golgi tendon organ

 D

Muscle spindle

Ans. C

Explanation:

C i.e. Golgi tendon organ

Golgi tendon organ functions as a transducer in a feed back circuit that regulates muscle force (tension)Q, whereas muscle spindle feed back circuit regulates muscle lengthQ & velocity.

Golgi tendon – Inverse stretch reflex

  • Golgi tendon organ is an encapsulated sensory receptor , consisting of a net like collection of knobby nerve endings among the fasicles of a tendon. There are 3 -25 (usually 10-15) muscle fibers connected to each golgi tendonQ.
  • Unlike muscle spindles, golgi tendon organs are in series with the muscle fibers, so they are stimulated by both passive stretch and active contraction of muscleQ. It is important to note that spindle detects muscle length and changes in muscle length, wheres golgi tendon detects muscle tension4. So it is stimulated when muscle fiber is tensed by contracting or stretching muscleQ.
  • Like primary receptor of muscle spindle, tendon organ has both a dynamic (intense response to sudden increase in tension) and static response (steady state firing of lesser degree almost directly proportional to muscle tension).
  • Impulses from tendon organ are transmitted through large, myelinated rapidly conducting sensory Ib nerve fibersQ (­161.1 dia). This Ib fibers end in the spinal cord on inhibitory interneuron, which inturn terminate on a – motor neuron supplying the muscle from which Ib originated. They also make excitatory connections with motor neurons supplying antagonist muscles. Stimulation of tendon organ causes inhibition of a – motor neuron whereas muscle spindle stimulation excites a motor neuron.
  • The threshold of golgi tendon is lowQ. Since more elastic muscle fibers take up much of the stretch, the degree of stimulation by passive stretch is not great, and strong stretch is required to produce relaxationQ. However, contraction of muscle regularly stimulate golgi tendon. It is responsible for inverse stretch reflex.

Q. 13

Receptor for inverse stretch reflex ‑

 A

Muscle spindle

 B

Extrafusal fibers

 C

Intrafusal fibers

 D

Golgi tendon organ

Q. 13

Receptor for inverse stretch reflex ‑

 A

Muscle spindle

 B

Extrafusal fibers

 C

Intrafusal fibers

 D

Golgi tendon organ

Ans. D

Explanation:

Ans. is ‘d’ i.e., Golgi tendon argan

Inverse stretch reflex (golgi tendon reflex)

  • Golgi tendon reflex is a bisynaptic reflex, initiated by the Golgi tendon organ located in muscle tendons.
  • This organ consists of a net-like (ramified) collection of knobby nerve endings among the fascicles of a tendon.
  • There are 3-25 muscle fiber per golgi tendon organ.
  • Golgi tendon organs are also stretch receptors.
  • However, unlike the muscle spindle which acts as a length detecter, the Golgi-tendon organ acts as a muscle tension-detector.
  • This difference in sensory function occurs because muscle spindle is located in parallel to the muscle fibers (extrafusal fibers) while the Golgi tendon organ is located in series to the muscle fibers (extrafusal fibers).
  • Therefore, Golgi tendon organs are stimulated by both passive stretch and contraction of muscle (in contrast to muscle spindle which is stimulated by passive stretch but is inhibited by active contraction of muscle).
  • Stimuli for golgi tendon reflex are both passive strech and active contraction of muscle.
  • The golgi tendon organ is innervated by Aa sensory (afferent) fibers (type lb sensory).
  • These afferent fibers terminate on an inhibitory interneuron in dorsal horn of grey matter in the spinal cord.
  • These inhibitory interneuron terminates on the a-motor neuron (same a-motor neuron on which Ia (Aa) afferent of stretch reflex terminates) and has inhibitory effect on a-motor neuron.
  • So, activation of Golgi tendon reflex results in relaxation of muscle.


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