Chapter 11 Part 2

Question 1

What percentage of neurons of CNS are on the cerebellum?

Answer 1

50

Question 2

What does the cerebellum do?

Answer 2

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

Question 3

What else is cerebellum involved in?

Answer 3

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

Question 4

Three layers of the cerebellum:

Answer 4

outer layer
middle layer
inner layer

Question 5

What are the neurons of the crerebellum?

Answer 5

principal: purkinje fibers

interneurons

Question 6

What are the afferent fibers of the cerebellum?

Answer 6

mossy fibers

climbing fibers

Question 7

Mossy fibers:

Answer 7

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

Question 8

Climbing fibers:

Answer 8

from inferior olivary neucleus; convey information regarding movement error

Question 9

Three lobes of cerebellum:

Answer 9

Anterior
Posterior
Flocculonodular

Question 10

Three groups of peduncles of cerebellum:

Answer 10

superior cerebellar peduncles
middle cerebellar peduncles
inferior cerebellar peduncles

Question 11

Superior cerebellar peduncles

Answer 11

to midbrain

Question 12

Middle cerebellar peduncles

Answer 12

receives input from pons

Question 13

Inferior cerebellar peduncles

Answer 13

bidirectional

Question 14

Cerebellar nuclei from medial to lateral are

Answer 14

Fastigial nucleus
Globose
Emboliform
Dentate

Question 15

Vertically, the cerebellum can be divided into sections:

Answer 15

Midline vermis
Paravermal hemisphere
Lateral hemisphere

Question 16

What are the three anatomic regions or functional divisions ?

Answer 16

vestibulocerebellum (flocculonodular lobe)
spinocerebellum
cerebrocerebellum

Question 17

Three broad classes of human movement:

Answer 17

Elquilibrium
Gross movement of limbs
fine, distal, voluntary movement

Question 18

Equilibrium:

Answer 18

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

Question 19

Gross movements of limbs:

Answer 19

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

Question 20

Fine, distal, voluntary movements:

Answer 20

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

Question 21

Unilateral lesions of cerebellum affect:

Answer 21

same side of the body

Question 22

Why are cerebellar signs ipsilateral?

Answer 22

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

Question 23

Ataxia:

Answer 23

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

Question 24

What results in truncal ataxia?

Answer 24

Lesions to vermal and flocculonodular lobe

Question 25

What do prarvermal lesions result in?

Answer 25

gait and limb ataxia

Question 26

What do lateral cerebellar lesions result in?

Answer 26

hand ataxia

Question 27

Limb ataxia resulting from spinocerebellar lesions has what manifestations:

Answer 27

dysdiadochokinesia dymetria action tremor

Question 28

Dysdiadochokinesia

Answer 28

inability to rapidly pronate and supinate the forearm

Question 29

Dysmetria:

Answer 29

inability to rapidly move an intended distance

Question 30

Action tremor

Answer 30

shaking of the limb during voluntary movement

Question 31

What can also produce ataxia?

Answer 31

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

Question 32

What can also produce ataxia in lower limbs?

Answer 32

Sensory deficits or paravermal cerebellar lesions

Question 33

How is cerebellar and somatosensory ataxia differentiated?

Answer 33

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

Question 34

What is the Romberg test:

Answer 34

Measures the ability to use proprioceptive information for standing balance

Question 35

How is Romberg test performed?

Answer 35

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

Question 36

What is criteria for failure of the Romberg test?

Answer 36

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

Question 37

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

Answer 37

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

Question 38

How to sensory ataxia individuals present?

Answer 38

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

Question 39

What is impaired with sensory ataxia?

Answer 39

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