week 12 part 1

Question 1

Automatic stereotype motor response in reaction to a sensory stimulus

Answer 1

Stimuli from peripheral receptors
Circuitry entirely within the spinal cord

Question 2

Basic components of the loop

Answer 2

Sensory neurons
Interneurons
Motor neurons

Question 3

Stretch reflex

Answer 3

Contraction of muscle when the muscle is lengthened maintains muscle length (excitatory)
Mediated by spindle – type 1a
Monosynaptiv - response (it is fast because it synaptic right onto the type Ia)

Question 4

Stretch reflex autogenic excitation

Answer 4

Divergence of Ia affernt - Ia affernt projects to
All motor neurons of the same homonymous muscle which is known as autogenic excitation
Many motor neurons of synergists
Amplification effect pf single Ia afferents
Example of divergence; excite/ project to many alpha motor neurons

Question 5

reciprocal Ib GTO

Answer 5

Active muscle contraction activates GTO
Inhibitory feedback via Ib afferent
Di synaptic connection to motor neurons via Ib inhibitory neurons to inhibit agonist

Question 6

Autogenic inhibition- inhibition of an agonist via Ib

Answer 6

Ib GTO inhibition reciprocal excitation (2)
Ib feedback also has excitatory (facilitatory) effect on antagonist motor neurons
Facilitation via inhibition of an inhibition (thus, facilitating or excitation)
Reciprocal excitation - activate antagonist via Ib

Question 7

Flexor (withdrawal) reflex

Answer 7

Protective reflex
Coordinated response in limb flexor muscle pull away from pain
Extensor motor neurons inhibited all flexors to pull away from pain

Question 8

Crossed extensor reflex

Answer 8

Occurs in the opposite limb
Activation of extensors and inhibition of flexors to stabilize the body so other limbs can move away from pain
(both occur at the same time)

Question 9

Flexor reflex

Answer 9

Protective reflex
Coordinated response in limb flexor (extensors inhibited)

Question 10

Crossed extension reflex

Answer 10

Opposite limb
Activation of extensor & inhibition flexors