Structure of the Cerebellum Flashcards
whats the cerebellum
its the motor part of the brain
(an older brain area with a simple regular architecture)
what does the cerebellum make up
10% of the brain volume but it contains 50% of the brains neurons i.e. it has 4x as many neurons as the cerebral cortex
whats the cerebellum necessary for
smooth, accurate performance of motor actions
what happens if someone doesn’t have a cerebellum
they can still move but their actions wont be coordinated
what are the function of the cerebellum
-maintains equilibrium
-controls posture
-muscle tone i.e. it coordinates muscle contraction in both stereotype and non-stereotype (voluntary movements)
where is the cerebellum located
on lower part of the posterior cranial fossa
what separates the cerebellum from the occipital lobe
tentorium cerebelli
the cerebellum lies behind what
posterior aspect of the pons and medulla
the cerebellum forms the roof of what
4th ventricle
the cerebellum contain what
2 cerebellar hemispheres (left & right)
the vermis in the central part which unites the hemispheres
the surface of the cerebellum bears what
curved fissures between narrow folds called folia
what are the fissures of the cerebellum
primary fissure
posterolateral fissure (on inferior surface)
the primary fissure divides the cerebellum into what
anterior lobe
posterior lobe
what does the posterolateral fissure of the cerebellum do
it separates the flocculonodular lobe from the body of the cerebellum ( corpus cerebelli)
whats the superior vermis
a slight ridge which extends anteriorly to include the lingula of medullary vellum
what demarcates the inferior vermis
vallecula cerebelli
the vermis is antero-posteriorly divided into what
nodule
uvula
pyramid
what does the nodule extend
a stalk to the flocculus forming the flocculonodular lobe
whats the tonsil
a partially separated lobule that over hangs the inferior vermis
where is the anterior lobe of the cerebellum
marked behind by the primary fissure
what makes up the posterior lobe of the cerebellum
the remainder of hemispheres + uvula= + pyramid
what makes up the flocculonodular lobe of the cerebellum
nodule + flocculum
what are the 3 cerebellar lobules and what are they divided into
anterior- divided into 3 lobules
posterior- divided into 7 lobules
flocculonodular
what are the 10 lobules
- lingula
- central
- culmen
- declive
- folium
- tuber
- pyramis
- uvula
- tonsil
- flocculonodular
whats the first phylogenetic division of the cerebellum to develop
the archcerebellum with the vestibular nuclei
the archcerebellum is well developed what
fish
in humans how is the archcerebellum represented
by :
flocculonodular lobe + lingula
vestibular system
the archcerebellum is involved in what mechanics
mechanics of balance (equilibrium)
whats the 2nd phylogenetic division of the cerebellum to develop
paleocerebellum
the paleocerebellum is well developed in what
reptiles
in humans how is the paleocerebellum represented
by:
anterior lobe
anterior and posterior vermis
how does the paleocerebellum connect to the spinal cord
through motor neurons for muscle tones
whats the last phylogenetic division of the cerebellum to develop
the neocerebellum (posterior lobe)
the neocerebellum is well developed in what
humans
what does the neocerebellum control
non-stereotyped skilled learned activities
what do the cerebellar peduncles do
connect the cerebellum to the brainstem
the cerebellar peduncles convey what
inputs and outputs from parts of the body to the cerebellar cortex
what are the 3 cerebellar peduncles
superior peduncle (brachium conjuctivum)
middle peduncle (branchium pontis)
inferior peduncle (restiform body)
what does the superior peduncle connect
the cerebellum to the junction of the pons and the midbrain
what does the superior peduncle contain
both afferent and efferent fibers to the red nucleus ( at the level of the superior colliculus) and thalamus
what does the middle peduncle connect
the cerebellum to the pons
what does the middle peduncle contain
afferent fibers from the pontine nuclei of the contralateral side
what does the inferior peduncle connect
the cerebellum to the medulla oblongata
what fibers does the inferior peduncle carry
afferent and efferent i.e.
-carries spinocerebellar fibers from the spinal cord
-carries from medulla oblongata i.e. cuneocerebellar fibers from nucleus cuneatus
-carries reticuocerebellar fibers to cerebellum
-carries climbing fibers from the inferior olivary nucleus to cerebellum
the middle cerebellar peduncle involves fibers from what
contralateral pons to cerebellum
the superior cerebellar peduncle efferent fibers leave the cerebellum to go to the
thalamus and spinal cord
the cerebellum consists of what components
cortex/surface layer (gray matter)
medullary center (white matter)
where is the gray matter of the cerebellum contained
in transverse folds/ folia
what does the white matter of the cerebellum contain
4 pairs of deep intracerebellar nuclei
where does the deep intracerebellar nuclei lie
in the roof of the 4th ventricle hence called roof nuclei
what are the deep cerebellar nuclei
fastigial nucleus
globose nucleus
emboliform nucleus
dentate nucleus
where does the fastigial nucleus lie
close to midline on the anterior surface of the superior vermis
the fastigial nucleus is well developed in what
fish
what does the fastigial nucleus control
the functions of the arch cerebellum
where does the globose nucleus lie
on lateral side of the fastigial but medial to the emboliform nucleus
what does the globose nucleus control
functions of the paleocerebellum
where does the emboliform nucleus lie
on the medial side of the dentate
what does the emboliform nucleus control
functions of the paleocerebellum
where is the dentate nucleus located
it occupies the center of the cerebellar hemispheres
what does the dentate nucleus have
a hilum that faces medially
the dentate nucleus is well developed in what
humans
what does the dentate nucleus control
functions of the neocerebellum
what are the 3 layers of the cerebellar cortex
molecular layer
purkinje layer
granular layer
the molecular layer consists of what
axons and dendrites of various cerebellar neurons
what are the sublayers of the molecular layer
stellate cell layer
basket cell layer
what neurotransmitter does the stellate cell release
where do the afferent fibers of the stellate cell come from and where do the efferent fibers of the stellate cells go to
taurine which is inhibitory
afferent-parallel fiber
efferent-purkinje cell dendrite
what neurotransmitter does the basket cell release
where do the afferent fibers of the basket cell come from and where do the efferent fibers of the basket cell go to
GABA which is inhibitory
afferent- parallel fiber
efferent- purkinje cell soma
what makes up the purkinje fiber layer
purkinje cells
what happens in the purkinje fiber layer
climbing fibers synapse with dendrites of purkinje fibers in the molecular layer
what neurotransmitter do the purkinje cells release
GABA which is inhibitory
where do the afferent fibers of the purkinje cell layer come from
parallel fiber
climbing fiber
stellate cell
basket cell
where do the efferent fibers of the purkinje cell go to
the deep cortical nuclei
