cerebellum Flashcards
What structure covers the cerebellum?
The tentorium cerebelli.
Where is the cerebellum located?
In the posterior cranial fossa.
What is the largest part of the hindbrain?
The cerebellum.
Which structures lie in front of the cerebellum?
The fourth ventricle, pons, and medulla oblongata.
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What connects the two cerebellar hemispheres?
The narrow median vermis.
What connects the cerebellum to the brainstem?
Three pairs of cerebellar peduncles.
Name the three cerebellar peduncles.
- Superior cerebellar peduncles
- Middle cerebellar peduncles
- Inferior cerebellar peduncles
How many lobes does the cerebellum have?
Three lobes.
Name the three lobes of the cerebellum.
- Anterior lobe
- Middle (posterior) lobe
- Flo(cculo)nodular lobe
Which fissure separates the anterior lobe from the middle lobe?
The primary fissure.
Which is the largest lobe of the cerebellum?
The middle (posterior) lobe.
Where is the flocculonodular lobe located?
Behind the uvulonodular fissure.
What divides the cerebellum into superior and inferior surfaces?
The deep horizontal fissure.
What are the two main components of the cerebellum?
- Outer gray matter (cerebellar cortex)
- Inner white matter with embedded nuclei
What are folia in the cerebellar cortex?
Coronal/transverse folds in the cerebellar cortex.
What are the two components of each folium?
- Core of white matter
- Superficial gray matter
What is the branched tree-like appearance of the cerebellum in midline section?
The arbor vitae.
How many layers does the cerebellar cortex have?
Three layers.
Name the three layers of the cerebellar cortex.
- Molecular layer (outer)
- Purkinje cell layer (middle)
- Granular layer (inner)
What are the two types of neurons in the molecular layer?
- Stellate cells (outer)
- Basket cells (inner)
What structures are found in the molecular layer?
- Dendritic arborizations
- parallel fibers
- scattered neuroglial cells.
What type of neurons are found in the Purkinje cell layer?
A single row of large, flask-shaped Purkinje neurons.
Where do Purkinje cell dendrites extend?
Into the molecular layer, branching profusely.
Where do Purkinje cell axons go?
Through the granular layer into the white matter, synapsing with intracerebellar nuclei.
Where do some Purkinje axons bypass the cerebellar nuclei?
They synapse directly in the vestibular nuclei.
What type of neurons are in the granular layer?
Numerous small granule cells.
Describe the dendrites of granule cells.
They have multiple dendrites forming claw-like endings.
What do granule cell axons form in the molecular layer?
Parallel fibers that synapse with Purkinje dendrites.
What type of interneurons are scattered throughout the granular layer?
Golgi cells.
Which cerebellar region controls midline structures?
The vermis.
Which body regions does the vermis control?
The neck, shoulders, thorax, abdomen, and hips.
Which cerebellar zone controls distal limb muscles?
The intermediate zone.
Which cerebellar zone is involved in movement planning and correction?
The lateral zone.
How many pairs of intracerebellar nuclei are there?
Four pairs.
List the intracerebellar nuclei from lateral to medial.
- Dentate nucleus 2. Emboliform nucleus 3. Globose nucleus 4. Fastigial nucleus
Which is the largest intracerebellar nucleus?
The dentate nucleus.
What is the shape of the dentate nucleus?
A crumpled bag.
Which cerebellar nucleus lies medial to the dentate nucleus?
The emboliform nucleus.
What is the shape of the emboliform nucleus?
Oval.
Which nucleus is medial to the emboliform nucleus?
The globose nucleus.
What is the shape of the globose nucleus?
Rounded clusters of cells.
Which intracerebellar nucleus is closest to the midline?
The fastigial nucleus.
Where is the fastigial nucleus located?
Near the midline, close to the fourth ventricle.
What type of neurons make up the intracerebellar nuclei?
Large multipolar neurons with simple branching dendrites.
Where do intracerebellar nuclear axons project?
To the brainstem and spinal cord.
What are the three types of fibers in the cerebellar white matter?
- Intrinsic fibers 2. Afferent fibers 3. Efferent fibers
What is the function of intrinsic cerebellar fibers?
They stay within the cerebellum and connect different regions.
What is the function of afferent cerebellar fibers?
They carry sensory input to the cerebellar cortex.
Through which peduncles do most afferent fibers enter?
The inferior and middle cerebellar peduncles.
What is the function of efferent cerebellar fibers?
They carry output signals from the cerebellum.
Where do efferent cerebellar fibers originate?
Purkinje cell axons.
Which nuclei send efferent fibers through the superior cerebellar peduncle?
The dentate, emboliform, and globose nuclei.
Which nucleus sends efferent fibers through the inferior cerebellar peduncle?
The fastigial nucleus.
What are the two main excitatory inputs to the cerebellum?
- Climbing fibers 2. Mossy fibers
Where do climbing fibers originate?
The olivocerebellar tract.
What is the function of climbing fibers?
They wrap around Purkinje cell dendrites and make multiple synapses.
How many climbing fibers synapse on a single Purkinje cell?
Only one.
How many Purkinje cells can a single climbing fiber connect to?
1–10 Purkinje cells.
Where do mossy fibers originate?
All cerebellar afferent tracts except the olivocerebellar tract.
What is the function of mossy fibers?
They create a diffuse excitatory effect by stimulating granule cells.
What are the three main sources of afferent fibers to the cerebellum?
- Cerebral cortex 2. Spinal cord 3. Vestibular nerve
Which neurotransmitter do climbing and mossy fibers use?
Glutamate.
Which neurotransmitters modify glutamate’s effects on Purkinje cells?
Norepinephrine and serotonin.
What is the primary function of Purkinje cells?
To send inhibitory signals to intracerebellar nuclei.
What are the four primary types of input the cerebellum receives for motor control?
- Cerebral cortex 2. Proprioception 3. Vestibular system 4. Tectum
How does the cerebellum refine movement?
It adjusts motor commands to inhibit agonist muscles, stimulate antagonist muscles, and control precision.
