Cerebellum - Sufaro

Question 1

What are the primary functions of the cerebellum?

Answer 1

1. The maintenance of posture and balance (nodular lobe)
2. The maintenance of muscle tone (posterior lobe)
3. The coordination of voluntary motor activity (anterior lobe)

Question 2

What is the vermis and what does it do?

Answer 2

Looks like a worm in the midline betweeen the two lateral cerebellar hemispheres

Balance and eye movements
Proximal trunk muscles
Distal appendicular muscles
Motor planning

Question 3

What are the three layers of cerebellum?

Answer 3

Molecular Layer
Dendrites and other molecules that supply cell
Is the outer layer that underlies the pia matter
Contains dendritic arborizations of Purkinje cells and the parallel fibers of the granule cells
Contains stellate (outer) cells and basket (inner stellate) cells

Purkinje Layer
Contains Purkinje cell bodies
The dendrites of the cells are covered by dendritic spines

Granular Layer
Takes input from outside
1. granule cells (Mossy fibers enter and terminate here)
2. Golgi cells
The axon of each granular cell passes into the molecular layer, where it bifurcates at a T junction = parallel fibers

Question 4

What are climbing fibers

Answer 4

Are the afferent excitatory fibers of the olivocerebellar tracts
Terminate on neurons of the cerebellar nuclei and on dendrites of Purkinje cells

Start at Purkinje cells, synapse at many dendrites of Purkinje cells in parallel

Question 5

What are the three arteries that supply the cerebellum?

Answer 5

All supply brainstem on the way to the cerebellum making a more proximal injury more dangerous

All from the Basilar artery

Superior cerebellar artery (SCA)

Anterior Inferior Cerebellar Artery (AICA)

Posterior Inferior Cerebellar Artery (PICA)

Question 6

What characterizes cerebellar dysfunction?

Answer 6

Is characterized by the triad
Hypotonia
is a loss in the resistance normally offered by muscles to palpation or to passive manipulation.
results in a floppy, loose-jointed, rag-doll appearance with pendular reflexes; the patient appears inebriated.

Disequilibrium
Refers to loss of balance, characterized by (wide) gait

Dyssynergia
Is a loss of coordinated muscle activity and includes:
Dysarthria, dystaxia, dismetria, intention tremor, dysdiadochokinesia, nystagmus, jerky decomposition, rebound or lack of check.