NM Spinal Level Reflexes

Question 1

Stretch (Myotatic) Reflex

Stimulus?

Answer 1

Muscle stretch

Question 2

Stretch (Myotatic) Reflex

Reflex arc?

Answer 2

Afferent 1a fiber from muscle spindle to AMN projecting back to muscle of origin (monosynaptic)

Question 3

Stretch (Myotatic) Reflex

Functions for maintenance of ______ ____, support _____ muscle contractions, and provide feedback around ______ _______

Answer 3

Muscle tone
Agonist
Muscle length

Question 4

Stretch (Myotatic) Reflex
Clinically, sensitivity of stretch reflex and intactness of spinal cord segment are tested by applying _______ to the _____ _____

Answer 4

Stretch

Deep tendons

Question 5

Stretch (Myotatic) Reflex

Reciprocal inhibition: via an inhibitory interneuron, the same stretch stimulus _________ the antagonist muscle

Answer 5

Inhibits

Question 6

Stretch (Myotatic) Reflex
Reciprocal innervation: Describes the effects of a stretch stimulus on agonist (_______ _______), antagonist (________ _______) and synergistic muscles (__________)

Answer 6

Autogenic facilitation
Reciprocal inhibition
Facilitation

Question 7

Inverse stretch (Myotatic reflex)
Stimulus?

Answer 7

Muscle contraction

Question 8

Inverse stretch (Myotatic reflex)
Reflex arc?

Answer 8

Multiple sensory receptors and corresponding fiber types activate inhibitory interneuron to muscle of origin (polysynaptic)

Question 9

Inverse stretch (Myotatic reflex)
Functions to provide \_\_\_\_\_\_ inhibition, diminution of force of \_\_\_\_\_\_ contraction, \_\_\_\_\_ \_\_\_\_\_\_ reflex

Answer 9

Agonist
Agonist
Stretch protection

Question 10

Gamma reflex loop:

______ ______ forms part of this loop

Answer 10

Stretch reflex

Question 11

Gamma reflex loop:

Allows muscle tension to come under control of which descending pathways?

Answer 11

Reticulospinal, vestibulospinal, and others

Question 12

Gamma reflex loop:
Descending pathways excite ____ ____ ____, causing contraction of ____ ____, and in turn increased stretch sensitivity and increased rate of firing from ______ ________

Answer 12

Gamma motor neurons
Muscle spindle
Spindle afferents

Question 13

Gamma reflex loop:

Impulses are then conveyed to _____ _____ _____

Answer 13

Alpha motor neuron

Question 14

Flexion (withdrawal) reflex

Stimulus?

Answer 14

Cutaneous sensory stimuli

Question 15

Flexion (withdrawal) reflex

Reflex arc?

Answer 15

Cutaneous receptors via interneurons to largely flexor muscles
Multisegmental response involving groups of muscles (polysynaptic)

Question 16

Flexion (withdrawal) reflex

Functions as a ________ withdrawal mechanism to remove body part from harmful stimuli

Answer 16

Protective

Question 17

Crossed extension reflex:

Stimulus?

Answer 17

Noxious stimuli and reciprocal action of antagonists
Flexors of one side are excited, causing extensors on same side to be inhibited
Opposite responses occur in opposite limb

Question 18

Crossed extension reflex:

Reflex arc?

Answer 18

Cutaneous and muscle receptors diverging to many SC motor neurons on same and opposite side (polysynaptic)

Question 19

Crossed extension reflex:

Function?

Answer 19

Coordinates reciprocal limb activities, such as gait