Control L16 cerebellum Flashcards
What brain structures are control centres for regulating activity of descending pathways?
Cerebellum
Basal ganglia
What are the three functional subdivision of the cerebellum?
Vestibulocerebellum
Spinocerebellum
Cerebrocerebellum
What are the functions of the cerebellum?
To co-ordinate movements (time, force and duration of muscle contraction)
Maintain equilibrium, balance and posture
may store instructions for patterns of movements
May have linguistic and cognitive functions
What is the positional anatomy of the cerebellum?
Found under the occipital lobes of the cerebral hemisphere and attached to the brainstem by three paired cerebellar peduncles (white matter fibre bundles)
What are the three cerebellar peduncles?
Superior cerebella peduncles (SCP)
Middle cerebellar peduncle (MCP)
Inferior cerebellar peduncles (ICP)
What is the gross anatomy of the cerebellum?
Has two hemispheres connected by the vermis.
Each hemisphere has two lobes - anterior and posterior lobes.
On inferior view has tonsils towards the midline
Also has flocculonodule lobe on the ventral/anterior aspect
Where can the tonsils of the cerebellum herniate and what structure is affected?
Through foramen magnum compressing the medulla
What is the vestibulocerebellum aka?
Archicerebellum
What is the function of the vestibulocerebllum?
Involved in balance and eye movements to maintain constancy of visual fields
What part of the cerebellum is the vestibulocerebellum?
The flocculonodular lobe and part of the vermis
What part of the cerebellum is the spinocerebellum?
Most of the vermis and adjacent region of cerebellar hemispheres
What is the function of the spinocerebellum?
Adjust muscle tone to co-ordinates muscles involved in posture and execute movement e.g. walking
What is the spinocerebellum aka?
Paleocerebellum
What is the cerebrocerebellum aka?
Neocerebellum
Where in the cerebellum is the cerebrocerebellum found?
In the lateral parts of the cerebellar hemispheres
What is the function of the cerebrocerebellum?
Co-ordinated movement of distal limbs - particularly fine, skilled and targeted movements of the hands
May also be involved in learning, linguistics and cognitive functions
How does the cerebellum influence the body? (Contralaterally/ipsilaterally)
Ipsilaterally I.e. right side of cerebellum controls right side of body
Where does the vestibulocerebellum receive information from?
From ipsilateral vestibular apparatus and vestibular nuclei in inner ear
What is the effector that the vestibulocerebellum sends a co-ordinated response to in response to information on balance?
Muscles and eye movements
What nerve is involved in the vestibulocerebellum receiving information from the inner ear?
Vestibular division of CN VIII (the vestibulocochlear nerve)
How does information from the vestibulocochlear nerve get to the midbrain?
Vestibulocerebellum afferent fibres from CN VIII pass through the vestibular nuclei and enter the vestibulocerebellum via the Inferior cerebellar peduncle
How does information from the vestibulocerebellum reach the effectors?
Cerebellovestibular efferent nerve fibres carry information from cerebellum out via the inferior cerebellar peduncle back to the vestibular nuclei where it synapses to lower motor neurones which travel through the vestibulospinal tract to muscles in body, and to the eyes (via CN III, IV and VI) and neck via the medial longitudinal fasciculus (MLF)
What is the medial longitudinal fasciculus (MLF)?
A specialised and heavily myelinated nerve bundle adjacent to CN III and IV in the midbrain extending to the inferior and dorsal pons at the level of CN VI, sending signals from the vestibular nuclei to these cranial nerves to co-ordinate eye movement (ascending MLF) and the ventral grey horn of the cervical spinal cord to co-ordinate movement to in the lower motor neurones of the neck (descending MLF)
Where is is the vestibular nuclei located?
In the caudal pons and rostral medulla
