Cerebellum Flashcards
function of the cerebellum
control centre for coordination of voluntary muscle activity, equilibrium and muscle tone of the SAME side
why does a person with cerebellar injury not become paralysed
what effects does injury cause
it does not initiate movement
movements are slow, clumsy, tremulous and uncoordinated
hypotonic muscles
unable to walk steadily
what steady stream of information does the cerebellum need to receive
position of the body parts in space
equilibrium state of the body
commands being sent from motor cortex to lower motor neurons
how does the cerebellum integrates information
by means of feedback pathways
where is the cerebellum located
posterior cranial fossa between the cerebral hemisphere and brainstem
primary posterolateral fissures cerebellum
divide it into anterior, posterior and flocculonodular lobes
longitudinal divisions of cerebellum
into midline vermis and left and right hemispheres
cerebellar cortex role
receives inputs
how is the cerebellum connected to the brainstem
three bundles of axons
superior, middle and inferior cerebellar peduncle
how is afferent proprioception information from proprioceptive fibres conveyed to cerebellum
via dorsal or ventral spinocerebellar tracts
cell bodies of these neurons are in DRGs
how is cerebellar surface area increased
folliae []
dorsal spinocerebellar tract route
axons from DRG synapse with second-order neurons in dorsal horn
axons ascend on the same side in terminate on the cerebellum of the same side as the DRG
where are second order synapses with DRGs in the dorsal horn
upper part of spinal cord
C8-L2
deep cerebellar nuclei
example
source of efferent information
dentate nucleus
how does the dorsal spinocerebellar tract enter the cerebellum
second-order neurons pass into lateral columns which forms the tract
enters through the inferior cerebellar peduncle
ventral spinocerebellar tract route
other axons conveying proprioception from the DRG enter junction and synapse between dorsal and ventral horns
axons cross the midline to ascend on the opposite side but then cross back to enter cerebellum
roles of dorsal and ventral spinocerebellar tracts
main bundles supplying proprioceptive impulses to the cerebellum
how does the cerebellum receive input about head position and rotation
from the vestibular apparatus in the inner ear through the vestibulocochlear nerve (CN VIII) `
where do fibres that supply information concerning equilibrium state of the body arise
where do they enter the cerebellum
superior and vestibular nuclei
through the ipsilateral inferior peduncle
function of cortico-ponto-cerebellar pathway
when the cerebral motor cortex discharges it brings information about the nature of the discharge to the cerebellum
route of corticopontocerebellar tract
fibres originate in motor cortex and descend through the internal capsule
synapse on neurons in the pontine nuclei
axons cross the midline and terminate in the cerebellum on the opposite side
what information does the cerebellum receive
muscle position and tonus
equilibrium
motor discharge to the muscles from the cerebral cortex
