Chapter 11 Part 2 Flashcards

1
Q

What percentage of neurons of CNS are on the cerebellum?

A

50

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2
Q

What does the cerebellum do?

A

Coordinates movement and postural control by comparing actual motor output with the intended movement and then adjust the movement as necessary

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3
Q

What else is cerebellum involved in?

A

Is involved in learning timing and rhythm of movements, synchronization of movements, and learning to correct motor errors

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4
Q

Three layers of the cerebellum:

A

outer layer
middle layer
inner layer

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5
Q

What are the neurons of the crerebellum?

A

principal: purkinje fibers

interneurons

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6
Q

What are the afferent fibers of the cerebellum?

A

mossy fibers

climbing fibers

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7
Q

Mossy fibers:

A

from spinal cord, reticular formation, and vestibular system ; convey information regarding sensory, equilibrium and motor information

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8
Q

Climbing fibers:

A

from inferior olivary neucleus; convey information regarding movement error

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9
Q

Three lobes of cerebellum:

A

Anterior
Posterior
Flocculonodular

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10
Q

Three groups of peduncles of cerebellum:

A

superior cerebellar peduncles
middle cerebellar peduncles
inferior cerebellar peduncles

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11
Q

Superior cerebellar peduncles

A

to midbrain

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12
Q

Middle cerebellar peduncles

A

receives input from pons

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13
Q

Inferior cerebellar peduncles

A

bidirectional

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14
Q

Cerebellar nuclei from medial to lateral are

A

Fastigial nucleus
Globose
Emboliform
Dentate

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15
Q

Vertically, the cerebellum can be divided into sections:

A

Midline vermis
Paravermal hemisphere
Lateral hemisphere

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16
Q

What are the three anatomic regions or functional divisions ?

A

vestibulocerebellum (flocculonodular lobe)
spinocerebellum
cerebrocerebellum

17
Q

Three broad classes of human movement:

A

Elquilibrium
Gross movement of limbs
fine, distal, voluntary movement

18
Q

Equilibrium:

A

Is regulated by the vestibulocerebellum (flocculonodular lobe) that receives information from vestibular receptors, and sends information to the vestibular nuclei; influence eye movements and postural muscles

19
Q

Gross movements of limbs:

A

Are coordinated by the spinocerebellum which receives proprioceptive information from muscle spindles and visual and auditory information; control ongoing movements through medial and lateral motor tracts

20
Q

Fine, distal, voluntary movements:

A

Are coordinated by the cerebrocerebellum that is related to processing in the cerebral cortex and coordinate movements via lateral motor tracts

21
Q

Unilateral lesions of cerebellum affect:

A

same side of the body

22
Q

Why are cerebellar signs ipsilateral?

A
  1. output paths of medial tracts remain ipsilateral
  2. cerebellar efferents project to contralateral cerebral cortex and red nucleus whose descending tracts cross the midline
23
Q

Ataxia:

A

describes the uncoordinated voluntary, normal-strength, jerky, and inaccurate movements that are not due to hypertonia or contracture

24
Q

What results in truncal ataxia?

A

Lesions to vermal and flocculonodular lobe

25
Q

What do prarvermal lesions result in?

A

gait and limb ataxia

26
Q

What do lateral cerebellar lesions result in?

A

hand ataxia

27
Q

Limb ataxia resulting from spinocerebellar lesions has what manifestations:

A

dysdiadochokinesia
dymetria
action tremor

28
Q

Dysdiadochokinesia

A

inability to rapidly pronate and supinate the forearm

29
Q

Dysmetria:

A

inability to rapidly move an intended distance

30
Q

Action tremor

A

shaking of the limb during voluntary movement

31
Q

What can also produce ataxia?

A

Interference with transmission of somatosensory information to the cerebellum, either by lesions of the spinocerebellar tracts or by peripheral neuropathy,

32
Q

What can also produce ataxia in lower limbs?

A

Sensory deficits or paravermal cerebellar lesions

33
Q

How is cerebellar and somatosensory ataxia differentiated?

A

Romberg test, tests of proprioception, vibration sense, and ankle reflexes

34
Q

What is the Romberg test:

A

Measures the ability to use proprioceptive information for standing balance

35
Q

How is Romberg test performed?

A

Patient stands with his or her feet together, first with eyes open for 30 seconds and then with eyes closed for 30 seconds
pass or fail

36
Q

What is criteria for failure of the Romberg test?

A

moving the arms to maintain balance, opening the eyes during the eyes closed section, beginning to fall, or requiring assistance

37
Q

How do cerebellar limb ataxia individuals present in the Romberg test:

A

unable to stand with feet together, with or without vision, and have normal vibratory sense, proprioception, and ankle reflexes

38
Q

How to sensory ataxia individuals present?

A

are able to stand steadily with feet together with eyes open for 30 seconds, but balance is impaired when the eyes are closed

39
Q

What is impaired with sensory ataxia?

A

Conscious proprioception and vibratory sense are impaired, ankle reflexes are decreased or absent