Cerebellum

Question 1

Division of cerebellum

Answer 1

1) Archicerebellum / vestibulocerebellum
- foculonodular + lingula of vernix
- balance and equilibrium
- lesion - ataxia, nystagmus, loss of balance

2) paleo cerebellum/ spinocerebellar
- Anterior lobe + uvula and pyramid of vernix
- co ordination and regulations of tone
- hypotonia

3) Neocerebellum / cerebrocerebellum
- Posterior lobe (middle) + remaining vernix
- smooth activity of voluntary motor activities
- dysarthria, dysdiadochokinesia, dysmetria, intentional tremor.

Question 2

Structure of cerebellum

Answer 2

3 layer

1) outer (molecular layer) - dendrite of Purkinje cell, stellate, basket cell
- receive excitatory input from parallel cell and inhibitory synapse with Purkinje.
2) middle Purkinje cell - flash shaped
3) inner - granular and Golgi with axon of Purkinje.
- receive excitatory input from mossy fibers.
4) cerebellar nuclei

Purkinje communicate with cerebellar nuclei which communicate with other part of brain.

Out put from cerebellum is carried by cerebellar nuclei
Out put from cerebellar cortex is by Purkinje cell.

All cell in cerebellum is inhibitory except granular.

Signal from other part of brain —> directly to Purkinje (climbing fibers) —> cerebellar nuclei
Signal —> (mossy fibers) —> Golgi or granular cells —> Purkinje cell —≥ cerebellar nuclei

Question 3

Afferent fibers

Answer 3

1) climbing - from Inferior olivary nucleus of opposite side to only one Purkinje cell
2) mossy fibers - divide into 4-5 terminal from spinal cord and brainstem and terminate on granular cells.
- each terminal forms cerebello glomerular with granualr and Golgi cells. T shaped fibers from granular cells forms parallel fibers is excitatory and anastomosis with large number of Purkinje.

Intrinsic components

• granular cell backwards inhibition - by Golgi cells - prevent transmission from mossy fibers to granular cells
• Purkinje cell forward inhibition - by stellate and basket cells.

≥ stellate, basket, Golgi and Purkinje - GABA
⟩ granular - glutamate

⟩ climbing and mossy are excitatory - use glutamate and aspartate

Question 4

Nucleus from cerebellum

Answer 4

Lateral to medial

1) Dentate - new
2) emboliform
4) globose
3) fastigial - oldest - by inferior peduncle, remaining from superior cerebellar penduncles.

2+4 - nucleus interpositus

Question 5

Cerebellar penduncles

Answer 5

1) superior - midbrain
- afferent - Anterior spinothalamic
Tecto cerebellar
- efferent - globus emboliform rubral pathway
- decussation at Inferior colliculus
- ends in c/l thalamus via red nucleus (brain stem)
- also contains ventrocerebellar track

2) middle - pons
- c/l cortico ponto cerebellar afferent
- no efferent

3) Inferior cerebellar - medulla
Affrent - Posterior spinocerebellar, cuneocerebellar, olivocerebellar, reticulocerebellar, trigeminocerebellar, vestibulocerebellar
efferent from fastigial vestibular and fastigial reticular nucleus end in vestibular nucleus.

Question 6

1) Ataxia telangiectasia

Answer 6

1) progressive degeneration of granular cells and Purkinje cell.

Question 7

1) blood supply

Answer 7

• superior cerebellar
• posterior inferior cerebellar
• Anterior Inferior cerebellar