Cerebellum

Question 0

Ways the cerebellum differs from the cerebral cortex

Answer 0

Finer arrangement of transverse gyri “folia” and sulci gives greater expansion of surface area compared to cortex.
None of its activity directly contributes to consciousness.
Its hemispheres possess ipsilateral representation of body parts.

Question 1

Location of cerebellum

Answer 1

• In posterior cranial fossa.
• Inferior to the cerebrum, under the tentorium cerebelli
• Posterior to the pons and medulla oblongata

Question 2

Functions of the cerebellum

Answer 2

1. maintenance of posture and balance
2. maintenance of muscle tone
3. Coordinates smooth movements by influencing timing and force of contractions of voluntary muscles.

Question 3

Cerebellar lobes: Anterior lobe

Answer 3

Maintains coordination of limb movements wile movements are being executed.
Receives input from limb (chiefly lower limb), muscle spindles (stretch receptors) and Golgi tendon organs via the spinocerebellar tracts.
Role in regulation of muscle tone

Question 4

Cerebellar lobes: Flocculonodular lobe (vestibulocerebellum)

Answer 4

• Consists of nodulus (of the vermis) and the flocculus (most ancient part of cerebellum).
• Receives input from vestibular system so it can monitor the position of the body in space.
• Play a role in maintenance of posture and balance and eye movements.

Question 5

Cerebellar lobes: Posterior lobe

Answer 5

• Lies between primary fissure and posterolateral fissure.
• Receives massive input from cerebral cortex.
• Plays role in co-ordination of voluntary motor activity.
• Stores all sequential components of skilled movements.

Question 6

Superior cerebellar peduncle

Answer 6

Connects cerebellum to pons and midbrain.

Contains mostly EFFERENT (“going out”) tracts from cerebellar nuclei.

Question 7

Middle cerebellar peduncle

Answer 7

Connects the cerebellum to the pons.

Contains only AFFERENT (“coming in”) tracts

Question 8

Inferior cerebellar peduncle

Answer 8

Connects the cerebellum to the medulla.

Contains both AFFERENT and EFFERENT tracts.

Question 9

Dorsal spinocerebellar tract (afferent)

Answer 9

Carries proprioceptive information from muscles spindles and tendon organs of individual lower limb muscles to the cerebellum via inferior cerebellar peduncle.

Question 10

Cuneocerebellar tract (afferent)

Answer 10

Carries equivalent information from upper limb which also enters via inferior cerebellar peduncle

Question 11

Trigeminocerebellar tract (afferent)

Answer 11

Carries info from TMJ, masticatory and external ocular muscles

Question 12

Ponto-cerebellar tract (afferent)

Answer 12

Carries info from motor cortex to cerebellum through contralateral middle cerebellar peduncle

Question 13

Vestibulocerebellar tract (afferent)

Answer 13

Vestibulocerebellar impulses from vestibular nuclei carry info about position and movement of head and enter cerebellum through inferior cerebellar peduncle.

Question 14

Four nuclei containing most of efferent neurons

Answer 14

Dentate nucleus (most lateral, largest – input from lateral parts of hemispheres)
Emboliform nucleus - Interposed nuclei
Globose nuclei - -
Fastigial nucleus (most medial – input from vermis & flocculonodular lobes)

Question 15

Layers of cerebellar cortex

Answer 15

• Molecular layer (outer layer)
• Purkinje cell layer
• Granular layer
• White matter of cerebellum deep to granular layer contains cerebellar nuclei.

Question 16

Blood supply

Answer 16

• Posterior inferior cerebellar artery (PICA)
• Anterior inferior cerebellar artery (AICA)
• Superior cerebellar artery (SCA)