BB2 Revision3 Flashcards
Cerebellar histology
label this A-C
A: purkinje layer
B: molecular layer (outer)
C: granular layer (inner)
Label A [1]
10 Flocculus of cerebellum
Label A-C
A: middle cerebellar peduncle
B: cerebellar hemisphere
C: Inferior cerebellar peduncle
Label A-E
A: Floccus
B: cerebellar tonsil
C: vermis
D: superior cerebellar peduncle
E: 4th ventricle
Label A
A: middle cerebellar peduncle
Label A
Superior cerebellar artery
What are the 3 layers of the cerebellum cells? [3]
- The outer, fibre-rich, molecular layer
- The intermediate, Purkinje cell layer
- The inner granular layer, which is dominated by the granule cell.
Label A-C
A: molecular layer
B: granular cell layer
C: Purkinje cells
Inputs and outputs to the cerebellum are via the [], which are either side of the []
Inputs and outputs to the cerebellum are via the cerebellar peduncles, which are either side of the pons
State if the following contain input or output fibres [3]
State where the fibres go to / come from
Superior cerebellar peduncle
Middle cerebellar peduncle
Inferior cerebellar peduncle
- Superior cerebellar peduncle has output fibres only. This is mainly going up to the motor thalamus
- Middle cerebellar peduncle (largest of the 3) contains input fibres from the contralateral cerebral cortex and cranial nerves
- Inferior cerebellar peduncle has input fibres from the spinal cord
Describe the course of the spinocerebellar tract (dorsal and ventral spinocerebellar tracts)
- first order neuron transmits sensation along the spinal nerve and travels via dorsal root in the spinal cord
- Dorsal (posterior) spinocerebellar tract: is wholly ipsilateral. Second order neuron stays on same side and enters cerebellum at inferior cerebellar peduncle on same side
- Ventral (anterior) spinocerebellar tract: is contralateral: Second order neuron crosses over, ascends and enters cerebellum where it crosses back over (terminate in the ipsilateral cerebellum.The fibres decussate twice – and so terminate in the ipsilateral cerebellum.
Name the 4 deep cerebellar nuclei [4]
What is their overall collective function? [1]
“Don’t Eat Greasy Food”
Dentate
Emboliform
Globos
Fastigial
Overall: Relay nuclei which information to the cerebellum passes through
Which part of the cerebellum is highlighted in green? [1]
Which part of the cerebellum does this structure connect to? [1
How does this part of the cerebellum differ in role to the deep cerebellar nuclei? 1[]
Flocculonodular lobe (anterior view)
Connects to the lateral vestibular nuclei of the pons
same function for the flocculonodular lobe as the deep nuclei do for the other cerebellar zones, but the difference is the deep relay nuclei for this lobe isn’t actually in the cerebellum.
Cerebellum function
State and describe the location of the three functional zones of the cerebellum
Also state which cerebellar nuclei related to each zone [4]
- Vestibulocerebellum comprises the flocculonodular lobe and its connections to the lateral vestibular nucleus of the pons
- Spinocerebellum comprises the anterior lobe and vermis, connected to the fastigial, globose and emboliform nuclei
- Cerebrocerebellum is comprised of the posterior lobe (cerebellar hemispheres) controlled by the dentate nucleus
State the function of the spinocerebellum [1]
Via which tract are motor commands from the spinocerebellum sent down? [1]
The spinocerebellum (anterior lobe and vermis) controls locomotion and limb coordination, and balancing your body the ground
It sends motor commands down the reticulospinal tracts to coordinate postural and locomotor movements: i.e. when you run, walk, lean over to grab something, you don’t lose balance and fall over.
(This is a more dynamic balance when compared to the vestibulocerebellum which is more of a static balance)
State the function of the cerebrocerebellum [1]
From where do the inputs for the cerebrocerebellum come from in the brain [1] & the cerebellum? [1]
From where do the outputs for the cerebrocerebellum go to in the brain [1] & the cerebellum? [1]
Which deep nuclei is involved with the cerebrocerebellum? [1]
Cerebrocerebellum: coordinates movements initiated by the motor cortex. This includes speech, voluntary movements of hands, arms, and hand-eye coordination. It is also involved in speech coordination
Input = from cerebral cortex via middle cerebellar peduncle
Output: To motor thalamus via superior cerebellar peduncle
Deep nuclei involved = dentate
What is the function of the vestibulocerebellum? [2]
- coordinates head and eye movements to ensure the stability of gaze.
- It controls balance of the head on the body via the medial vestibulospinal tract and helps balance of the body on the ground via the lateral vestibulospinal tract
Cerebellar pathologies:
Why do tumours from ependymal cells specifically compress the cerebellum? [1]
What is the name for these types of tumours? [1]
Medulloblastoma:
Tumours which grow from the ependymal cells grows in the 4th ventricle, and it tends to grow in the midline so very specifically compresses the nodulus of the cerebellum.
What is the most common type of CNS tumour in children? [1]
Medulloblastoma: tumours arising from cerebellum
What are the symptoms of flocculonodular syndrome? [3]
little control of axial muscles, wide based ataxic gait with reeling and swaying
Why do alcoholics often suffer from anterior lobe syndrome? [1]
brain needs B12 for myelin generation and the cerebellum has a higher turnover than most parts of the brain meaning it needs more, so if depleted in alcoholics it causes problems
What are the characteristics of anterior lobe syndrome? [4]
- incoordinaion of the limbs (especially legs)
- ataxic gait (walks in a wide platform so they don’t fall over, this overlaps with flocculonodular syndrome).
- hypotonia
- reflexes appear depressed or pendular (UMN lesion)
Neocerebellar syndrome occurs due to damage to which functional part of the cerebellum? [1]
What are characterisitic features of neocerebellar syndrome? [5]
Damage to the cerebrocerebellum
Characterisitc features:
* Loss of hand-eye coordination.
* Dysmetria (inaccurate reaching with intention tremor)
* Dysdiadochokinesis (the irregular performance of rapid alternating movements of the hands)
* Intention tremors occur on an attempt to touch an object
* Loss of good speech articulation/slurred speech which is due to a loss of coordination of muscles involved in speech production
Name 6 characteristics of cerebellar stroke
Dysdiadochokinesia: is the inability to perform rapid alternating muscle movements
Ataxia (gait and posture)
Nystagmus
Intention tremor
Slurred, staccato speech
Hypotonia/heel-shin test
- . Headache, vertigo, nausea, vomiting
- . Eye changes (nystagmus, ptosis)
- . Dysarthria and dysphagia (Dysarthria is a motor disorder of speech weakening the muscles of the mouth, face and respiratory system)
- . Ataxia
- . Arm weakness and incoordination
What is the difference in symptoms between a lesion in Broca’s area to Cerebrocerebellum? [1]
Broca’s lesions to do with forming words in the right sequence and getting the right grammar
Cerebrocerebellum can speak fine but they slur due to improper movement ( basics of moving the mouth and lips to make the right sounds)
Label A & B
A: inferior cerebellar peduncle
B: Vestibular nuclei
Desribe the pathway of the lateral spinothalamic tract [3]
First-order neurones”
- cell bodies are in the dorsal root ganglion whose axons extend from peripheral receptors
Second-order neurones
- cross almost immediately via the anterior spinal commissure and form the lateral spinothalamic tract
- Then ascends in the lateral funiculus. Fibres of this tract are somatotopically organised for their entire course.
Third-order VPL neurons:
- send axons through the posterior limb of the internal capsule to the somatosensory cortex (areas 3, 1, 2).
