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SP16 Anatomy > Neuro L6 > Flashcards

Neuro L6 Flashcards

1
Q

Importance of Lower motor neuron

A

Only way movement can be initiated

“Last neuron in chain of neurons”

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2
Q

Alpha motor neurons project to

A

extrafusal muscle fibers

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3
Q

Gamma motor neurons project to

A

intrafusal muscle fibers

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4
Q

Lower motor neuron lesion can cause (5)

A 
Atonia: loss of muscle tone (floppy)
Areflexia: loss of knee jerk reflex
Flaccid paralysis
Fasciculations: spont. muscle contractions
Atrophy: loss of muscle tissue
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5
Q

Upper motor neuron lesion causes

A

Spastic paralysis (paresis)
-hypertonia (increased resting tension in arm flexors and leg extensons
-hyperreflexia
Babinski sign

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6
Q

Babinksi sign

A

Big toe dorsoflexion

fanning of other toes when heal is stoked

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7
Q 
LMN vs UMN
Strength
Muscle tone
Stretch relfex
Atrophy
Other
A 
decrease decrease
decrease increase
decrease increase
severe mild
fasciculation and fibrillations vs clonus pathologic reflexes (babinski)
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8
Q

Arrangement of motor neurons
Axial
Flexors
Extensors

A

(All still in anterior horn)
Axial muscles are more medial
Flexors are posterior
Extensors are anterior

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9
Q

Motor unit

A

1 motor neurons plus all myofibers it innervates

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10
Q

Large antigravity muscles vs extraocular muscles

Myofibers/motor unit

A

Extraocular: 10 (10 myofibers/1neuron)
Antigravity: 100s (100s of myofibers/1 neuron)

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11
Q

True or false: One motor unit my contain several different muscle fiber types

A

False: there is no mixing

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12
Q

Type 1 muscle

A 
One
Slow
Fat (lipids)
Red 
Ox (mitochondira)
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13
Q

Type 2 muscle

A 
Fast
Little lipid
High glycogen
Little mitochondria
White
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14
Q

Damage to basal ganglia, cerebellum or cerebral cortex will cause

A 
DOES NOT cause weakness
DOES CAUSE
Involuntary movements
Incoordination
Difficulty initiating movements
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15
Q

Basal ganglia, cerebellum, and cortex role in movement

A

design, choice and monitoring of movement
BUT NO direct effect on LMN
Outputs go to motor and premotor cortex NOT spinal cord

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16
Q

Hierarchical order of motor control

A

Premotor cortex plans
Motor cortex
LMN

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17
Q

Parallel arrangement of motor control

A

Premotor cortex can talk directly to LMN

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18
Q

Most descending motor pathways synapse where

What are the exceptions

A

interneurons in spinal cord

some directly with primary motor neuron (hand and CST)

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19
Q

Main descending motor pathways

A

Corticospinal: cortex to spinal cord
Corticobulbar: cortex to brainstem
Corticopontine: cortex to basilar pons

20
Q

Primary motor area
Area number
Function

A

Area 4 precentral gyrus
Contralateral voluntary movements
Control fine digital movements

21
Q

Somatic sensory area

A

Post central gyrus (brachmanns 312)

22
Q

Supplementary motor
Area number and location
Function

A 
Area 6 medial surface of cerebrum
Plans movements while thinking
Learns no sequences
Assembles previously learned sequences
Imagines movements
23
Q

Premotor area
area number and location
function

A

area 6: lateral surface of cerebrum

Plans movements in response to external cues

24
Q

Corticospinal tract areas

A 
Primary motor
Somatic sensory
Premotor
Supplementary motor
Superior parietal lobule
25
Q

Lesion of Area 4 causes

A

(primary motor cortex)

paralysis of contralateral muscles

26
Q

Premotor area has control over

A

proximal and axial musculature

Empathetic facial movements

27
Q

Premotor area projects to

A

primary motor area
reticular formation
spinal cord levels

28
Q

Lesion in lateral area 6

A

(premotor)
moderate weakness of contralateral proximal muscles
Inability to associate learned hand movements to verbal or visual cues

29
Q

supplemental motor area projects to

A

premotor and primary motor areas

30
Q

Parietal lobe areas
Project to (2)
Function (2)

A

Somatic sensory (312)
Superior parietal lobe (5,7)
Project to primary motor: direct patterns in response to sensory impu
Project to sensory brainstem and spinal cord: modulate sensory signals

31
Q

True or false: All movements depend on CST

A

False

32
Q

CST descent

A 
Cerebral cortex, precentral gyrus
cerebral peduncle
Pons
pyramids
pyramidal decussation
80% contralateral lateral funiculus
10% ipsilateral lateral funiculus
10% ipsilateral anterior funiculus
33
Q

Corticospinal fiber location on cerebral peduncle

A

middle third

34
Q

Reticulospinal tract
function
May support

A

control axial musculature- walking

may suppor recovery of motor funtions

35
Q

Tectospinal tract function

A

head turning reflexes in response to visual stimuli..unclear function in humans

36
Q

Vestibulospinal tract

Function

A

postural adjustments and head movements
antigravity reflexes
(righting reflex in cats)

37
Q

Vestibulospinal tract

pathway

A

look at sheet

38
Q

Rubrospinal tract

Origin

A

Red nucleus

39
Q

Rubrospinal tract

function

A

upper extremity flexor muscles

Like that of vestibulospinal tract

40
Q

Rubrospinal tract

Pathway

A

Look at sheet

41
Q

Reticulospinal tract Origin

A

Reticular formation

42
Q

Reticulospinal tract

Pathway

A

Look at sheet

43
Q

Corticobulbar pathway

Fiber ending directly on motor neuron

A

CN XII

44
Q

Corticobulbar pathway gives no direct input to these CNs

A

III
IV
VI

45
Q

Corticobulbar decussation

A

Descend with CST so no corticobulbar decussation exists

46
Q

Exception to typical CBP pattern

A

Facial motor nucleus

47
Q

Unilateral damage to CBP

A

inability to smile or show teeth symmetrically

forehead unaffected

SP16 Anatomy (11 decks)

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