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Cerebellum
Anatomy
47
Medical
Graduate
11/16/2009

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Cards

Term
Which way will a patient fall if they have a cerebellar lesion?
Definition
ipsilateral side
Term
What is disequilibrium?
Definition
inability to maintain proper balance; disruption of input from the vestibular system
Term
What is hypotonia?
Definition
decreased muscle tone and difficulty in maintaining posture; from disruption of spinal cord inputs
Term
What is asynergia?
Definition
lack of coordination of muscles which usually work together; from damage to pathways from higher levels (cerebral cortex) or lower levels (spinal cord)
Term
What is ataxia?
Definition
inability to coordinate voluntary movements
Term
What is an intention tremor?
Definition
most apparent during a planned movement just before the patient reaches the target
Term
What is dysmetria?
Definition
overshoot or undershoot reaching a target
Term
What are folia?
Definition
parallel, horizontal folds called folia on surface; run from left to right
Term
What is the the vermis?
Definition
midline region
Term
What are the cerebellar hemispheres?
Definition
lateral lobes surrounding vermis
Term
What is the intermediate zone?
Definition
located between vermis and cerebellar lobes
Term
What are the three lobes created by the deep transverse fissures?
Definition
anterior, posterior, and flocculonodular
Term
What is the fissure separating the anterior and posterior lobes?
Definition
primary
Term
What is the fissure separating the posterior and flocculonodular lobes?
Definition
postlateral
Term
What is another name for the flocculonodular lobe? Why is it called this?
Definition
the vestibulocerebellum due to its major inputs from the vestibular system
Term
What is another name for the anterior lobe? Why?
Definition
called the spinocerebellum due to its inputs coming mainly from spinal cord
Term
What is the posterior lobe also known as? Why?
Definition
neocerebellum or cerebrocerebellum, due to its inputs mainly from cerebral cortex via the pons
Term
What is the posterior lobe also known as? Why?
Definition
neocerebellum or cerebrocerebellum, due to its inputs mainly from cerebral cortex via the pons
Term
What is the inferior cerebellar peduncle? What does it do?
Definition
contains fibers entering the cerebellum; outputs to the to the medulla oblongata, vestibular nuclei, and reticular formation
• attaches the cerebellum to the medulla oblongata
Term
What is the middle cerebellar peduncle? What does it do?
Definition
fibers entering the cerebellum from the pons
• attaches the cerebellum to the pons
Term
What about the superior cerebellar peduncle?
Definition
contains outputs of the cerebellum to the red nucleus and VA/VL thalamus
Term
What are the subregions of the cerebellum?
Definition
cerebellar cortex, medullary center, deep cerebellar nuclei, cerebellar peduncles
Term
Cerebellar cortex?
Definition
matter, composed of three neuron layers and located on the surface under the pia mater
Term
Medullary center?
Definition
under the cerebellar cortex and contains axons, which are coming and going to the cerebellar cortex
Term
What are the four deep cerebellar nuclei? Where are they located?
Definition
fastigial nucleus, globose nucleus, emboliform nucleus, dentate nucleus;dorsal to the fourth ventricle
Term
What are the inputs of the cerebellum?
Definition
spinal cord axons, inferior olivary nucleus inputs, reticular formation inputs, vestibular nuclei and vestibular ganglion cell axons,cerebral cortex via relays through the pons
Term
Explain the where and what of spinal cord inputs.
Definition
• synapses mainly in the anterior lobe of the cerebellum
• conveys information regarding muscle tone for the extremities
Term
What are the where and what of inferior olivary nucleus inputs?
Definition
• cross in the medulla oblongata and enters cerebellum in the inferior cerebellar peduncle
• axons project to the entire cerebellar cortex
Term
The where and what of reticular formation inputs?
Definition
• axons enter the cerebellum in inferior cerebellar peduncle
• axons project mainly to spinocerebellum
Term
Vestibular nuclei and vestibular ganglion cell axons?
Definition
• axons enter cerebellum in the inferior cerebellum peduncle
• axons project mainly to the vestibulocerebellum
Term
What is the name of the nuclei where axons from the cerebral cortex synapse?
Definition
pontine grey
Term
What do the pontocerebellar axons do?
Definition
cross in pons to enter cerebellum by the middle cerebellar peduncle
• motor areas of cerebral cortex project to the cerebellum via the pons
Term
What are the cell that leave the cerebellum?
Definition
 purkinje cells are the only neurons whose axons leave the cerebellar cortex and they mainly go to the neurons in the cerebellar deep nuclei
Term
Fastigial nucleus?
Definition
located next to the midline
Term
Globose nucleus?
Definition
several small groups of grey matter located lateral to fastigial nucleus
Term
Emboliform nucleus?
Definition
wedge-shaped nucleus located lateral to globose nucleus
Term
What makes up the interposed nucleus?
Definition
globose and emboliform
Term
Are the outputs of the cerebellum excitatory or inhibitory?
Definition
excitatory
Term
What are the inputs of the outputs?
Definition
from Purkinje cell axons and collaterals from the mossy and climbing fibers
Term
What is the molecular layer of the cortex?
Definition
(located under the pia mater) contains large bundles of parallel fibers and dendrites of the Purkinje cells
Term
What is the purkinje cell layer?
Definition
• spread out into the molecular layer where they receive excitatory synapses from parallel fibers and climbing fibers
• purkinje cell axons leave cerebellar cortex to synapse on deep cerebellar nuclei neurons
• Purkinje cells are inhibitory
Term
What is in the granular layer?
Definition
granule cells whose axons form the parallel fibers, which run in molecular layer and synapse on dendrites of Purkinje cells
• parallel fibers are excitatory
Term
What are mossy fibers?
Definition
 originate from neurons in spinal cord, reticular formation, vestibular system and pons
 synapse mainly with granule cells
 as they enter cerebellar cortex, they send collateral axons to deep cerebellar nuclei neurons
 excitatory
Term
What are climbing fibers?
Definition
 originate from neurons in the inferior olive
 synapse mainly on dendrites of Purkinje cells in the molecular layer
 as they enter cerebellar cortex, they send collateral axons to deep cerebellar nuclei neurons
 excitatory
Term
How does the fastigial nucleus affect somatic motor activity?
Definition
 receives inputs from the Purkinje cells of vermis, vestibular nuclei and vestibular ganglion cells
• output to vestibular nuclei and reticular formation
o concerned with extensor muscle tone and adjusting posture
Term
How does the globuse and emboliform nuclei affect somatic motor activity?
Definition
 inputs from Purkinje cells in intermediate zone
• output to red nucleus mainly, but also VA/VL thalamus
o concerned with flexor muscle and limb movements
Term
How does the dentate nucleus affect somatic motor activity?
Definition
 inputs from Purkinje cells located in the lateral cerebellar hemisphers
• output to red nucleus and VA/VL thalamus
o concerned with coordinating somatic motor activities by influencing motor regions of cerebral cortex, coordinates finger movement, and skilled movements
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