lecture 10: motor systems Flashcards

1
Q

true or false: motor pathways are usually 3 neurons

A

false, 2

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2
Q

where are the upper motor neuron cell bodies located

A

in cortex (or brainstem)

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3
Q

where are the lower motor neuron cell bodies located

A

in ventral horn or brainstem

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4
Q

UMN are CNS or PNS

A

CNS

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5
Q

LMN are CNS or PNS

A

PNS

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6
Q

upper motor neuron axons comprise tracts or nerves

A

tracts (central nervous system)

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7
Q

lower motor neuron axons comprise tracts or nerves

A

nerves (peripheral n system)

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8
Q

LMN innervate what

A

muscles

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9
Q

the motor pathways are broadly divided in what 2 systems

A

1) lateral motor system
2) medial motor system

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10
Q

the lateral motor system contains what info

A

control of appendicular muscles

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11
Q

control of appendicular muscles is laterlal or medial system

A

lateral

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12
Q

the medial motor system controls what

A

control of axial muscles (eg: postural tone)

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13
Q

control of axial muscles (eg: postural tone) is lateral or medial motor system

A

medial

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14
Q

what are the 3 divisions of the lateral motor system

A

lateral corticospinal
lateral reticulospinal
rubrospinal

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15
Q

what are the 4 divisions of the medial motor system

A

medial reticulospinal
anterior corticospinal
vestibulospinal
tectospinal

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16
Q

what pathway contains our volunteary pathway to move

A

lateral corticospinal

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17
Q

be able to locate the pathways on the crossection of the SCq

A
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18
Q

what are the pyramidal pathways

(2)

A

corticospinal and corticonuclear

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19
Q

what category of pathway is control of musculature or trunk and limbs

A

(lateral and ) corticospinal

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20
Q

:)

what pathway is equivalent to corticospinal pathway but for synapses in the brainstem

A

corticonuclear

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21
Q

corticonuclear pathways synapse where

A

in the brain stem

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22
Q

what does the corticonuclear pathway control

A

musculature of the head and neck

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23
Q

musculature of the head and neck is associated with what pathway

A

corticonuclear

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24
Q

extrapyramidal pathways original where

A

in brainstem

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25
Q

extrapyramidal pathways originate in brainstem but receive cortical input via what and what is their purpose

A

corticofugal fibers

fibers that project from the cerebral cortex to nuclear masses in the brainstem and spinal cord (go to extrapyramidal)

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26
Q

what are the extrapyramidal pahthways

A

rubrospinal
tectospinal
reticulospinal
vestibulospinal

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27
Q

UMN cell bodies are located in what cortical motor area

A

Most in primary
(some in premotor and supplementary)

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28
Q

what is the function for cortical input from premotor and supplementary cortical

A

=supplemental
aids with planning of complex movement

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29
Q

rubrospinal pathway originates in what part of brainstem

A

red nucleus

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30
Q

tectospinal pathway originates in what part of brainstem

A

superior colliculi

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31
Q

reticulospinal pathway originates in what part of brainstem

A

reticular formation

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32
Q

vestibulospinal pathway originates in what part of brainstem

A

vestibular nuclei

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33
Q

all of the motor pathways synapse where (first synapse)

A

in anterior horn or brainstem

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34
Q

all of the motor pathways synapse where (second synapse)

A

axons will synapse with target tissue (skeletal muscle)

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35
Q

50% of the UMN are located where

A

in the primary motor cortex

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36
Q

if 50% of UMN are located in the primary motor cortex, where are the others located

A

premotor cortex
supplementary cortex

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37
Q

true or false, in the motor pathways primary motor cortex is somatotopically organized and explain

A

true
UMN synapse with LMN at different levels depending on where the UMN cell is located

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38
Q

are motor neurons pseudo unipolar or multipolar

A

multipolar

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39
Q

true or false: upper motor neurons axons pass thru the posterior limb of internal capsule

A

true

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40
Q

upper motor neuron axons form the BLANK of the internal capsule

A

the posterior limb

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41
Q

corticospinal fibers carry info for what region

A

trunk and limbs

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42
Q

corticonuclear fibers carry info for what region

A

head and neck

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43
Q

explain the somatotropin arrangement of the internal capsule

A

corticonuclear fibers (F:face) form the genu of the internal capsule

cortispinal fibers are arranged from rostral (C:cervical) to caudal (L:lumbosacral)

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44
Q

corticonuclear fibers from what aspect of the internal capsule

A

genu

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45
Q

corticosinal fibers from what aspect of the internal capsule

A

arranged from from rostral (C:cervical) to caudal (L:lumbosacral)

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46
Q

what is the anterior limb of the internal capsule comprised of

A

motor and sensory fibers

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47
Q

what is the motor aspect of the anterior limb

A

motor tracts include the corticofugal fibers
=cortical regulation of extrapyramidal pathways

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48
Q

motor tracts include the corticofugal fibers in anterior limb, what is their purpose

A

=cortical regulation of extrapyramidal pathways

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49
Q

explain location of UMN of corticospinal pathways axons in midbrain

A

UMN of corticospinal pathways in cerebral peduncles

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50
Q

UMN of corticospinal pathways in cerebral peduncles is in what aspect of the brainstem

A

midbrain

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51
Q

UMN of corticospinal pathways in cerebral peduncles, is that more ventral or dorsal

A

ventral

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52
Q

true or false, in the brainstem, motor pathways are located dorsal

A

false, ventral

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53
Q

UMN from corticospinal pathway cervical region are more lateral or medial in brainstem

A

medial

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54
Q

UMN in corticospinal pathway from lumbar region are more lateral or medial in brainstem

A

lateral

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55
Q

explain location of UMN corticospinal pathway axons in pons

A

UMN axons of cortispinal pathways in basilar (ventral) region of pons

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56
Q

explain the location of UMN of corticospinal pathway in rostral medulla

A

UMN axons of corticospional pathways in medullary pyramids

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57
Q

after entering the brainstem, the tracts formed by the UMN axons in the corticospinal pathway are found what region of the brainstem

A

ventral

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58
Q

true or false, somatotropin organization of motor patwhways is similar throughput and explain

A

true
cervical more medial
lumbar more lateral

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59
Q

be able to understand the location of corticospinal pathway in brainstem and the associated blood vessels

A
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60
Q

what blood vessel supplies the corticospinal UMNs in the midbrain

A

posterior cerebral

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61
Q

what blood vessel supplies the corticospinal UMNs in the pons

A

basilar artery

62
Q

what blood vessel supplies the corticospinal UMNs in the rostral medulla

A

anterior spinal a

63
Q

if there was a lesion of the anterior spinal artery in the rostral medulla, would only the medial lemnisuc be affected?

A

no , also the corticospinal tract

64
Q

decussation in the corticospinal pathway happens in what part of the brainstem

A

happens at the most caudal end of the brainstem

65
Q

true or false: decussation in the corticospinal pathway happens at the most rostral end of the brainstem

A

false, caudal

66
Q

90% of UMN in the corticospinal pathways decussate where

A

at the decussation of the pyramids (in the caudal medulla)

67
Q

do all UMN of the CS pathway decussate at the decussation of the pyramids

A

no , 90% do and the other UMN continue ipsilaterally

68
Q

decussation of the pyramids occurs at the BLANK end of the medulla

A

caudal

69
Q

decussation of the pyramids occurs at the caudal end of the medulla …. aka what junction

A

spinomedullary junction

70
Q

the UMN of the CS pathway that decussate form what tract in the spinal cord

A

the lateral corticospinal tract

71
Q

true or false: the UMN of the CS pathway that decussate form the anterior corticospinal tract in the spinal cord

A

false, the lateral corticospinal

72
Q

UMN of the lateral corticospinal tract stay ipsilateral, or go contra lateral

A

contralateral

73
Q

10% of UMN of the CS pathway go contralateral or remain ipsi

A

remain ipsilateral

74
Q

the 10% of UMN of the CS pathway that remain ipsilateral form what tract in the SC

A

form the anterior corticospinal tract

75
Q

axons of UMN in the lateral corticospinal tract go where in the spinal cord

A

lateral spinal column

76
Q

axons of UMN in the anterior corticospinal tract go where in the spinal cord

A

anterior spinal column

77
Q

in the dorsal column, what general pathway goes there

A

DCML (only sensory)

78
Q

in the lateral column, what general pathways go there

A

spinocerebellar
lateral corticospinal
(Motor and cerebellum)

79
Q

in the anterior column, what general pathways go there

A

anterior cortcispinal
spinothalamaic
(motor and sensory)

80
Q

axons of UMN in lateral CS tract control what

A

appendicular muscles (voluntary, skilled movements)

81
Q

axons of UMN in anterior CS tract control what

A

control of axial muscles
(postural tone and balance)

82
Q

upper motor neurons of corticospinal pathway synapse with LMN where

A

in ventral / anterior horns

83
Q

true of false, UMN of corticospinal pathway synapse with LMN in posterior/dorsal horn of SC

A

false, anterior

84
Q

the lateral corticospinal tract synapses ipsilateral or bilateral in anterior horn

A

ipsilateral

85
Q

the anterior corticospinal tract synapses ipsilateral or bilateral in anterior horn

A

bilateral
(has both ipsilateral and contralateral)

86
Q

true or false, the anterior corticospinal tract UMN has bilateral projections

A

true

87
Q

since the UMN of anterior corticospinal tract provide bilateral projections, explain how that would be implicated for lesion symptoms

A

symptoms are less visible/apparent because we have two tracts provided bilateral

=deficits will be minor

88
Q

UMN for upper limb synapse at what spinal levels

A

c5-ti

89
Q

UMN for lower limb synapse at what spinal levels

A

T2-L2

90
Q

explain the general pathway steps of the lateral corticospinal tract

A

1) UMN in primary motor cortex (pre central gyrus)
2) corona radiate
3) internal capsule (posterior limb)
4) cerebral peduncle
5) pyramid (decussation of the pyramids)
6) lateral corticospinal tract)
7) synapse with LMN in ipsilateral ventral horn
8) spinal nerve goes to target tissue (skeletal m)

91
Q

where is there primary motor cortex locatiedh

A

pre central gyrus (frontal lobe)

92
Q

how does UMN get from brain to brainstem

A

cerebral peduncles

93
Q

what is the pathway fir the anterior corticospinal pathway

A

1) UMN in primary motor cortex (pre central gyrus)
2) corona radiate
3) internal capsule (posterior limb)
4) cerebral peduncle
5) pyramid ((NO DECUSSATION)
6) ANTERIOR corticospinal tract)
7) synapse with LMN in ventral horn (ipsilateral and contralateral)
8) spinal nerve goes to target tissue (axial muscles)

94
Q

true or false: uMN lesions are always ipsilateral

A

false, LMN are

95
Q

UMN lesions can be contralateral or ipsilateral reparative to the lesion depending on what

A

on level of the lesion

96
Q

symptoms for UMN are always below the level or the lesion
or always at and below

A

always below the level of the lesion

97
Q

if an UMN lesion is above decussation, will the symptoms be ipsilateral or contralateral

A

contralateral

98
Q

if an UMN lesion is below decussation, will the symptoms be ipsilateral or contralateraleral

A

ipsilateral

99
Q

if you have both LMN symptom and UMN at the same level,, which wins

A

LMN

100
Q

what are the 3 general symptoms with an UMN

A

paresis/paralysis (no cortical input (UMN) to LMN)

spasticity, hyperrefflexia, altered tone
(LMN not regulated by UMN)

possible positive babinski sign

101
Q

explain why in UMN lesion you may see paralysis or paresis

A

paresis/paralysis (no cortical input (UMN) to LMN)

102
Q

explain why in UMN lesion you may see spasticity, hyper reflex, altered tone

A

(LMN not regulated by UMN)

103
Q

true or false, you can get hyporeflexia with an UMN

A

false, hypperreflexta

104
Q

explain the babinski sign

A

pathological reflex

when you swipe upwards on the foot base, the toes spread upwards
=normal in kids only

105
Q

in a LMN lesion, will the symptoms be contralateral, ipsilateral or both relative to the lesion

A

ipsilateral

106
Q

for LMN lesions, are the symptoms at or below the level of the lesion

A

at and below

107
Q

in LMN, the dysfunction is isolated to what

A

to myotomes associated with the damaged levels

108
Q

what are the general categories of symptoms for LMN

A

paresis, paralysis, hypo or areflexia
(loss of motor input to muscles via LMN)

muscle wasting/atrophy
(long term result of chronic muscle denervation)

fasciculations
(spontaneous firing of LMN and increased receptor concentration.sensitivty)

109
Q

explain why you might see paresis, paralysis, hypo or areflex in LMN lesion

A

loss of motor input to muscles via LMN)

110
Q

explain why you might see muscle wasting/atrophy in LMN lesion

A

(long term result of chronic muscle denervation)

111
Q

explain concept of fascinations for LMN lesions

A

if there are some motor neurons that have not been completely severed by a lesion they may become more sensitive to activation via the expression of more receptors and therefore are prone to spontaneouss firing

112
Q

what is the patellar refelx

A

l3-l4

113
Q

what is the calcanea reflex

A

s1-s2

114
Q

what is the biceps reflex

A

c5-c6

115
Q

what is the tricep reflect

A

c7-c8

116
Q

if you have a LMN lesion at c8, will tricep show areflexia or hyporeflexia

A

hyporeflexia (c7 still in tact)

117
Q

in the extrapyramadial tracts the UMN cell bodies are located where

A

in brainstem nuclei

118
Q

are the extrapyramidal tracts responsible for concious or non conous function

A

non concious

119
Q

the cell body in the rubrospinal tract is located where (specific)

A

red nucleus

120
Q

the cell body in the tectospinal tract is located where (specific)

A

superior colliculi

121
Q

the cell body in the reticulospinal tract is located where (specific)

A

reticular formation

122
Q

the cell body in the vestibulospinal tract is located where (specific)

A

vestibular nuclei

123
Q

rubrospinal tract faciliates flexors or extension

A

flexors

124
Q

when do UMN decussate in rubrospinal

A

decussate immediately to contralateral side

125
Q

true or false; rubrospinal is an archaic motor system

A

true

126
Q

what is the function of the tectospinal tract

A

reflexible movement related to auditory/visual stimuli

127
Q

when do UMN decussate in tectospinal

A

UMNs decussate immediately

128
Q

what is function of the reticulospinal tract

A

maintains posture/balance and refines movement

129
Q

the pontine fibers of the ritculospinal tract control what

A

extensors

130
Q

the medullary fibers of the ritculospinal tract control what

A

flexors

131
Q

do all UMN decussate in the reticulospinal tract

A

no . some UMN decussate and others stay ipsilateral

132
Q

what is the function of the vestibulospinal tract

A

controls antigravity extensor muscles to help maintain balance and posture
=stabilizes head

133
Q

do UMN of vestibulospinal tract go contralateral or stay ipsi

A

stay ipsilateral

134
Q

true or false: it is easy to park out damage to individual extrapyramidal tracts

A

false

135
Q

decerebrate signs are associated with what tract

A

rubrospinal tract

136
Q

red nuclei is in rostral or caudal midbrain

A

rostral

137
Q

if you see decerebrate posturing, is that extensor or flexor posturing

A

extensor

138
Q

if you see decorticate posturing, is that extensor or flexor posturing

A

flexor

139
Q

if you see decerebrate posturing, are the rubrospinal tracts damaged or intact

A

damaged

140
Q

if you see decorticate posturing, are the rubrospinal tracts damaged or intact

A

intact

141
Q

decerebrate rigidity is characterized by what

A

exaggerated extensor posturing (with flexed wrists)

142
Q

what is the most common type of disc herniation

A

subarticular

143
Q

explain subarticular herniation

A

When the disc extrudes between the spinal cord and the foramen

144
Q

what is the second most common type of disc herniation

A

foramina or extraformainal

145
Q

what is foraminal herniation

A

beneath and lateral to the vertebral facet,

146
Q

what is the most uncommon disc herniation

A

central

147
Q

what is central disc herniation

A

annulus fibrosus is damaged enabling the nucleus pulposus (which is normally located within the center of the disc) to herniate

148
Q

what is a common cause of lower back pain

A

herniation of the nucleus pulpous of the intervertebrall disc into or tjru the annulus fibrosis

149
Q

explain whyherniation of the nucleus pulpous of the intervertebrall disc into or tjru the annulus fibrosis is a common source of back pain

A

impingement of spinal cord, rootlets, roots, spinal nerves

150
Q

true or false: herniated discs are always symptomatic

A

false, often incidental findings

151
Q

central herniation of the intervertebral disc between L4 and L5 causes what

A

spares L4 nerves and compresses L5-Co nerves
=cauda equina syndrome

152
Q
A