motor system

Question 1

motor unit

Answer 1

a motor neuron and all of the muscle cells it innervates

Question 2

___ provide the only input to muscles

Answer 2

lower (alpha) motor neurons

Question 3

lower motor neurons found in

Answer 3

spinal cord(anterior gray horn) and brain stem
medial column-axial muscles
lateral column-more distal muscles of extremeties

Question 4

what type of receptors are muscle spindles

Answer 4

sensory receptors

Question 5

what is the result of the myotatic reflex

Answer 5

agonist muscles contract (alpha motor neuron)

antagonist muscles relax

Question 6

what is the reverse of inverse myotatic reflex

Answer 6

1a and II are the sensory neurons

1b-causes agonist to relax and antagonist to contract

Question 7

what types of neurons innervate intrafusal muscles

Answer 7

gamma motor neurons(proprioception)

produce changes in length of IF fibers to keep fiber sensitive

Question 8

lower motor neuron lesion results in

Answer 8

flaccid paralysis and severe atrophy
enduring flaccid paralysis
hypotonia
no superficial reflexes
reduced or absent deep tendon reflexes
fasiculations
atrophy

Question 9

corticospinal tract

Answer 9

volitional control, trunk and extremeties, fractionating finger movements, precision grip

Question 10

corticobulbar tract

Answer 10

volitional control, muscles of mastication, facial expression, tongue, vocal cords

Question 11

corticoreticular tract

Answer 11

voitional movements, cortical drive to neurons of reticulospinal tracts, reaching, power trip

Question 12

reticulospinals tract

Answer 12

postural control of proximal limb and trunk

Question 13

vestibulospinals

Answer 13

lateral-postural control

medial-part of system to coordinate head and eye movements

Question 14

tectospinal tract

Answer 14

reflex originating movements of head and eyes in response to visual, tactile, auditory stimuli

Question 15

origin of corticospinal tract

Answer 15

postcentral gyrus, primary motor cortex, premotor cortex, supple-mentary motor cortex

Question 16

postcentral gyrus’

Answer 16

efference copy, informing sensory structures of motor plan to optimize proprioceptive feedback related to the planned movement

Question 17

primary motor cortex

Answer 17

voluntary
finger movements
control of distal limb muscles associated with volitional movements

Question 18

premotor cortex

Answer 18

voluntary
reaching and grasping
specific movement
proximal limb muscles

Question 19

supplementary motor cortex

Answer 19

volitional movement
learning stimulus response asociations
mental rehearsal of skilled movements
inhibition of movement

Question 20

corticobulbars originate from

Answer 20

lateral and inferior portion of precentral gyrus

descend with corticospinal to brainstem levels to control motor neurons associates with cranial nerves

Question 21

corticospinals originate from

Answer 21

superior and medial regions and from premotor and supplementary motor cortices
descend to spinal cord to control motor neurons for the trunk and extremeties

Question 22

corticobulbar tract is in

Answer 22

genu of internal capsule

Question 23

corticospinal tract is in

Answer 23

posterior limb of internal capsule

Question 24

lateral corticospinal controls

Answer 24

trunk and extremeties

Question 25

anterior corticospinal controls

Answer 25

motor neurons that innervate neck soulder and upper trunk muscles

Question 26

medially descending pathways

Answer 26

anterior corticospinal
reticulospinal
tectospinal
vestibulospinal

Question 27

medial vestibulospinal tract function

Answer 27

participates with other structures to coordinate head neck and eye movements

Question 28

lateral vestibulospinal tract function

Answer 28

promotes movements to maintain posture and balance; especially involved in reflex actions to maintain upright posture

Question 29

tectospinal tract functions

Answer 29

to coordinate head movements and eye movements as part of reflex orienting to visual, auditory, and touch stimuli

Question 30

medial rectospinal tract originates from

Answer 30

pons

Question 31

lateral recticulospinal tract originates in

Answer 31

medulla

Question 32

reticulospinal tract function

Answer 32

cooperate with vestibulospinal

maintain posture and balance

Question 33

___only extend to upper thoracic spinal cord levels

Answer 33

anterior corticospinal and medial vestibulospinal tracts

Question 34

damage to corticospinal tract results in

Answer 34

weakness especially in distal musculature of extremeties

Question 35

what is muscle tone

Answer 35

the force with which a muscle resists being lengthened

Question 36

babinski reflex indicative of

Answer 36

corticospinal tract damage