Cerebellum

Question 1

tentorium cerebelli

Answer 1

connects cerebellum to cerebrum

Question 2

falx cerebelli

Answer 2

connects hemispheres of the cerebellum

Question 3

primary fissure

Answer 3

divides the cerebellum into rostral and caudal lobes

Question 4

vermis

Answer 4

entire midline of the cerebellum

Question 5

nodulus

Answer 5

most caudal and ventral part of the cerebellum

Question 6

flocculus

Answer 6

white matter tracts of the flocculonodular lobe located laterally to the nodulus

Question 7

flocculonodular lobe

Answer 7

vestibular component of the cerebellum

Question 8

caudolateral fissure

Answer 8

divides the caudal lobe of the cerebellum from the flocculonodular lobe

Question 9

folia

Answer 9

ridges; equivalent to gyri of the cerebrum

Question 10

arbor vitae

Answer 10

white matter branches throughout the cerebellum

Question 11

cerebellar peduncles

Answer 11

attach the cerebellum to the brainstem
- middle (most lateral)
- caudal (middle)
- rostral (medial)

Question 12

deep cerebellar nuclei

Answer 12

3 pairs of nuclei located within the white matter (deep medulla)
- denate
- interposital
- fastigial

Question 13

layers of the cerebellar cortex

Answer 13

1. molecular layer
2. Purkinje cell layer
3. granule cell layer

Question 14

main neuron type of the cerebellum

Answer 14

Purkinje - overall INHIBITORY

Question 15

molecular layer

Answer 15

outermost layer; contains fibers (axons/dendrites) from granule and Purkinje cell layers

Question 16

purkinje cell layer

Answer 16

middle layer; single layer of Purkinje neurons

Question 17

granule cell layer

Answer 17

innermost layer; multiple layers of smaller neurons that send processes into the molecular layer and split into 2 longitudinal strands that synapse with dendrites of Purkinje cells

Question 18

metencephalon

Answer 18

pons + cerebellum

Question 19

germinal cells

Answer 19

give rise to the cells of the cerebellum

Question 20

mantel cells

Answer 20

germinal cells that differentiate into Purkinje and deep cerebellar nuclei neurons
- do NOT divide

Question 21

external germinal layer cells

Answer 21

germinal cells that:
1. migrate to the cerebellar surface to form the external germinal layer
2. divide until 10-12 cell layers thick
3. stop dividing and migrate back into cerebellum
4. differentiate into granule neurons in the granular layer

Question 22

pyramidal tracts

Answer 22

axon tracts from the cerebrum that directly innervate motor neurons (CNs or spinal)

Question 23

extra-pyramidal tracts

Answer 23

all axon tracts that do not innervate motor neurons of cranial/spinal nerves
- reticular formation
- pons
- medulla

Question 24

function of the cerebellum

Answer 24

coordinates movement and posture
- “fine tunes” movement
- determines rate/range/force of movement
- assists with equilibrium and balance

does NOT initiate movement

Question 25

what side of the body does the cerebellum control

Answer 25

ipsilateral

Question 26

requirements for cerebellar function

Answer 26

1. sensory input from muscle spindles 2. feedback loops to/from motor command centers of cerebrum

Question 27

afferent pathways into cerebellum

Answer 27

1. spinal cord/cranial nerves 2. feedback loops with cerebrum

Question 28

spinocerebellar pathways

Answer 28

4 pathways that carry sensory information about proprioception from muscle spindles/joint receptors/golgi tendon organs - comes from spinal cord (dorsolateral aspect) and cranial nerves - somatotopic organization

Question 29

corticopontocerebellar feedback

Answer 29

feedback loops to/from cerebrum and cerebellum via the pyramidal system cerebral cortex --> pons --> cerebellar cortex

Question 30

extrapyramidal system

Answer 30

indirect (olivary nucleus) feed back loops direct (vestibular nuclei & tectum) feed back loops

Question 31

mossy fibers

Answer 31

afferent fibers whose main axon synapses on the granule cells in the cerebellum - sends collateral to cerebellar nuclei

Question 32

climbing fibers

Answer 32

afferent fibers whose axons wrap around one Purkinje neuron in the molecular layer - sends collateral to cerebellar nuclei

Question 33

efferent pathways out of cerebellum

Answer 33

1. neuron 1: inhibitory 2. neuron 2: excitatory function: coordinates contralateral side of cerebrum to affect ipsilateral side of the body

Question 34

neuron 1 (efferent pathway)

Answer 34

Purkinje cell in the cerebellar cortex with INHIBITORY effect on neuron 2 dictates the output of the cerebellum

Question 35

neuron 2 (efferent pathway)

Answer 35

located in deep cerebellar nuclei; projects to extrapyramidal/pyramidal tracts output activity is influenced by inhibitory function of Purkinje cells

Question 36

functional regions of the cerebellum

Answer 36

1. vestibular: flocculonodular lobe 2. proprioceptive: vermis 3. feedback: pyramidal/extrapyramidal projections

Question 37

overall effect of cerebellar dysfunction

Answer 37

inability to measure and regulate motor function

Question 38

clinical signs of cerebellar dysfunction

Answer 38

signs are IPSILATERAL to lesion: ataxia dysmetria vestibular signs head tremor (intention tremor) increased muscle tone menace reaction deficits postural reaction deficits (delayed, exaggerated, or normal) NO paresis or paralysis No effects on facial expression, vision, or palpebral reflexes

Question 39

intention tremor

Answer 39

dysmetria of the head; tremor during an intended movement

Question 40

acute decerebellation

Answer 40

dysfunction of the entire cerebellum signs: opisthotonus

Question 41

cerebellar hypoplasia

Answer 41

underdeveloped cerebrum due to hypoplasia of the granule layer - idiopathic - can be caused by viral infections or live vaccines in utero/early postnatal - non-progressive - present at birth