Functional Heirarchy of the Motor System

Question 1

what type of motor neurons control voluntary movement

Answer 1

alpha motor neurons

Question 2

reflexes are voluntary/autonomic

Answer 2

autonomic

Question 3

true/false brainstem nuclei exert control over spinal reflexes

Answer 3

true - vestibulospinal and reticulospinal tracts regulate trunk and limb muscle reflexes

Question 4

part of brain that initiates and terminates movements

Answer 4

basal ganglia

Question 5

purpose of cerebellum in movement

Answer 5

coordination

Question 6

what is the final common path of movement

Answer 6

motor neuron pools acting on skeletal muscles

Question 7

the medial white matter in the spinal cord originates from the cortex/brainstem

Answer 7

brainstem

Question 8

the lateral white matter in the spinal cord originates from the cortex/brainstem

Answer 8

cortex

Question 9

which limb muscles are mapped most laterally in the spinal cord grey matter

Answer 9

distal muscles (fingers)

Question 10

descending tract of movement

Answer 10

corticospinal/pyramidal tract

Question 11

what muscles are stretch reflexes found in

Answer 11

all muscles

Question 12

stretch reflex arc is mono/polysynaptic

Answer 12

monosynaptic

Question 13

what does monosynaptic mean

Answer 13

there are no interneurons involved - just two neurons and one synapse

Question 14

when an agonist muscle contracts the antagonist muscle …

Answer 14

relaxes

Question 15

what is reciprocal inhibition

Answer 15

when afferent spindle neurons from the stretched muscle activate inhibitory interneurones to the antagonist muscle

Question 16

true/false spindle afferents travel up the spinal cord to the somatosensory cortex

Answer 16

true - they ascend through the dorsal column to tell the somatosensory cortex about the length of muscles

Question 17

what type of feedback loop is stretch reflex

Answer 17

negative feedback loop

Question 18

example of when a stretch reflex is utilised

Answer 18

when you have a sudden weight to carry

Question 19

what is an inverse stretch reflex

Answer 19

the clasp knife reflex - golgi tendon organs monitor muscle tension and when it becomes too great the clasp knife reflex is activated inhibting the agonist and exciting the antagonist

Question 20

in a clasp knife reflex which muscle is inhibited

Answer 20

the agonist

Question 21

purpose of the inverse stretch reflex

Answer 21

prevents the muscle from contracting so hard as to tear the tendon away from the bone

Question 22

flexor reflexes are mono/polysynaptic

Answer 22

polysynaptic

Question 23

stimulus of a flexor reflex

Answer 23

pain stimulus

Question 24

flexor reflex is accompanied by what action to prevent imbalance

Answer 24

contralateral inhibtion of flexors and excitation of extensors

Question 25

tract that flexor sensory information ascends to brain through

Answer 25

spinothalamic tract

Question 26

which is faster flexor and crossed extensor reflex or stretch reflex

Answer 26

stretch reflex - less interneurons and thicker nerve fibres that conduct faster

Question 27

can you override the GTO reflex

Answer 27

yes, it can be overriden by voluntary inout from the CNS

Question 28

how many synapses are there onto just 1 alpha motorneurone

Answer 28

~10,000

Question 29

how do we override the GTO reflex with voluntary input

Answer 29

by excitation of alpha motorneurons to override their inhibition from GTOs

Question 30

can the stretch reflex be overridden

Answer 30

yes - inhibition of alpha motorneurons, this is why reinforcement is a thing