Motor system Flashcards

1
Q

Describe the structure of the neuro system

A

CNS is brain
PNS is rest
PNS splits into Afferent sensory system (Info from body to brain) and efferent motor system (brain to body)
Then motor system splits into somatic and autonomic
Autonomic splits into symp and parasymp

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2
Q

What is classified as a lower motor neuron?

A

The spinal motor neuron innervating the muscle

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3
Q

What is classified as upper motor neuron?

A

The direct and indirect pathways leading to innervation of muscle

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4
Q

What are descending motor pathways?

A

pathways that carry info from cortex to lower motor neuron

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5
Q

what is the final motor pathway?

A

pathway that carries info from lower motor neuron to muscle

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6
Q

where in spinal motor neuron are neurons that fire to distal muscles?

A

more laterally

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7
Q

where are neurons that fire to trunk muscles

A

medial

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8
Q

where are neurons that fire to extensor muscles

A

ventral

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9
Q

where are the flexor muscles located?

A

dorsal

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10
Q

what is the ratio of alpha and beta neurons in ventral horn

A

70:30

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11
Q

are alpha and beta neurons myelinated?

A

yes

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12
Q

size of alpha motor neurons? beta?

A

12-20 microns

2-8 microns

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13
Q

Conduction velocity of alpha neurons? beta?

A

70-120

10-50

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14
Q

Function of extrafusal alpha neurons?

A

increase in muscle force

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15
Q

function of intrafusal beta neurons?

A

contractile properties of spindles

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16
Q

Properties of slow (red) motor unit?

A

high mitochondrial potential, long contractions,low tension in muscle, high oxygen consumption, low fatigue

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17
Q

properties of fast (white) motor unit

A

Low mitochondrial potentialm short contractions, high tension in muscle, low oxygen consumption, high fatigability

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18
Q

which motor units are recruited first?

A

slow and then fast (larger) when slow is fatigued

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19
Q

What is the funciton of the primary motor cortex?>

A

performance of voluntary skilled movement

20
Q

Upper motor neurons can have direct or indirect pathways

A

True

21
Q

What are the two pathways of the direct upper motor neurons?

A

Lateral corticospinal tract

Medial corticospinal tract

22
Q

What is the corticobulbar tract?

A

a corticospinal tract that innervates both hemispheres with the exception of facial and hypoglassal nerves

23
Q

discuss why facial nerves are an exception of bilateral innervation

A

Upper facial nerves are normal and get innervated bilaterally the lower facial nerves are only innervated by on side

24
Q

what happens to face if there is a facial nerve lesion?

A

contralateral upper and lower facial nerves will be affected (entire half of face will be off)

25
Q

What are the two divisions of the indirect upper motor neurons?

A

Lateral and medial

26
Q

what are the tracts in the lateral indirect upper motor neurons

A

Rubrospinal and medullary reticulospinal

27
Q

what are the tracts in the medial indirect upper motor neurons?

A

Tectospinal, pontine reticulospinal, vestibulospinal

28
Q

What are the divisions of Basal ganglia?

A

striatum (caudate nucleus + putamen), Globus pallidus, substantia nigra, subthalamic nucleus

29
Q

Function of basal ganglia?

A

plans and initiates complex movement, controls background tone

30
Q

what happens when basal ganglia is damaged?

A

movement changes, increased muscle tone, rigidity, dysarthria, resting tremor, chorea, tics

31
Q

what is hypertonia?

A

muscle tone

32
Q

Define dysarthria

A

problems finding words

33
Q

define chorea

A

repeated movements

34
Q

Divisons cerebellum?

A

vestibulocerebellum, spinocerebellym, cerebrocerebellum

35
Q

what direction of control does the cerebellum have?

A

ipsilateral

36
Q

What happens when cerebellum is damaged?

A

there is asynergia, dysmetria, intention tremor, ataxic gait, hypotonia, ataxic dyarthria, nystagmus

37
Q

define dysmetria?

A

inability to judge distance

38
Q

define hypotonia

A

weak muscles

39
Q

define ataxic dysarthia

A

slurred speech

40
Q

define asynergia

A

loss of control of motor movement

41
Q

Where is lesion in parkinsons patients?

A

in substantia nigra, accompanied by decreased dopamine levels in striatum

42
Q

symptoms of parkinsons?

A

rigidity, akinesia, bradykinesia, resting tremor

43
Q

what is the cause of huntingtons disease?

A

basal ganglia atrophy

44
Q

symptoms of huntingtons?

A

Chorea, muscle tone can be increased or decreased,

45
Q

symptom of vestibulocerebellum lesion?

A

loss of equilibrium during rapid direction changes

46
Q

symptom of spinocerebellum lesion?

A

unsteady walking, gait ataxia, hypotonia

47
Q

symptom of cerebrocerebellum lesion?

A

irregular movements of limbs, loss of coordination (dyssnergia), dysmetria, intention tremor