CH 16: Cerebellum Flashcards
the cerebellum participates in:
a wide variety of movements
it maintains the fine control and coordination of both simple and complex movements
the cerebellum is essential for:
coordinating posture & balance in walking/running
executing sequential movements in eating, dressing, writing
producing rapidly alternating repetitive movements and smooth pursuit movements: including trajectory, velocity and acceleration
voluntary movements can proceed without the cerebellum but would lack:
precision and appear clumsy and disorganized
the cerebellum not only participates in motor processes but also in certain:
specific cognitive functions
cerebellar damage has been implicated in:
disturbances of executing functioning
spatial cognition
aspects of personality
linguistic performance
what is the basic anatomy of the cerebellum?
where is it in the skull?
how does it attach to other structures?
the cerebellum consists of a bilaterally symmetrical structure that is situated in the posterior cranial fossa attaches to the medulla, pons and midbrain by 3 pairs of cerebellar peduncles
these peduncles lie at the sides of the 4th ventricle on the ventral aspect of the cerebellum
what is the tentorium cerebellum?
a transverse fold of the dura mater, stretches horizontally over the superior surface of the cerebellum and separates it from the overlying occipital lobes of the cerebrum
what is folia?
numerous parallel folds that corrugate the surface of the cerebellum
what is the cerebellar cortex?
a layer of gray matter that covers the surface of the cerebellum and encloses an internal core of white matter
what are the cerebellar nuclei?
4 pairs of deep cerebellar nuclei: from medial to lateral: fastigial globose emboliform dentate
what is the vermis?
cerebral hemispheres?
the cerebellum includes:
a midline structure in the cerebellum =vermis
2 large lateral masses= cerebral hemispheres
together these can be divided transversely into 3 lobes
what are the 3 transverse cerebellar lobes?
1- flocculonodular lobe
-paired flocculi
-nodulus
-separated from the posterior lobe by the posterolateral fissure
“archicerebellum”
-receives input from the vestibular nuclei
2- anterior lobe
-lies posterior to the primary fissure
“paleocerebellum”
-receives input form the spinocerebellar and trigeminocerebellar pathways
3- posterior lobe
-contains the major portions of the cerebellar hemispheres
“neocerebellum”
-contains the cerebellar tonsils - lie immediately above the foramen magnum
-receives projections from the cerebral hemispheres
what a disease process (tumor or hemorrhage) in the cerebellum increases pressure in the posterior fossa, the cerebellar tonsils can..?
herniate downward into the foramen magnum and can compress the medulla
this threatens survival because compression of the medulla leads to dysfunction of RF neurons in the BS that control BP and respiration
the cerebellum can be subdivided into 3 longitudinal strips arranged mediolaterally that include:
cerebrallar cortex
underlying white matter
deep cerebellar nuclei
what are the 3 cell layers of the cerebellar cortex?
1- molecular layer (outermost)
2- pukinje cell layer (middle)
3- granular layer (innermost)
describe the molecular layer of the cerebellar cortex
the outermost layer
Contains:
- 2 types of neurons (stellate cells, basket cells)
- dendrites of Purkinje and Golgi type II cells
- axons of granule cells
describe the Purkinje cell layer of the cerebellar cortex
middle layer
contains the cell bodies of Purkinje cells
- these large, flasklike neurons have enormous dendritic arborizations extending upward into the molecular layer
- run perpendicular to the million parallel fibers in the molecular layer
- long axons synapse either on deep cerebellar nuclei or vestibular nuclei
describe the granular layer of the cerebellar cortex
the innermost lawyer
contains massive numbers of granule cells (neurons), Golgi type II cells and glomeruli
glial cell processes encase each glomerulus