Neuroanatomy 3 Flashcards
How many lobes does the cerebellum have?
3 - anterior, posterior and flocculonodular
How does the cerebellum attach to the brainstem?
via 3 peduncles (‘feet’) - middle, superior, inferior
What separates the 2 hemispheres of the cerebellum?
Vermis (worm)
What are the 3 layers of the cerebelllar cortex?
Molecular layer (outer) - few neurones, lots of synapses
Purkinje layer
Granular layer - lots of neurones
Why is the granular layer of the cerebellar cortex a dark colour?
Because there is a vast number of neuones
Is the cerebellum a contralateral or ipsilateral organ?
Ipsilateral
What are the 3 functional units of the cerebellum?
Cerebrocerebellum - planning movements and motor learning
Spinocerebellum - regulating body movements, error correction and receives proprioceptive info
Vestibulocerebellium - controlling balance and occular reflexes
What would a unilateral hemispheric lesion in the cerebellum cause?
Disturbance in co-ordination in limbs, unsteady gait and intention tremor
What would a midline lesion in the cerebellum cause?
Disturbance of postural control
What would a bilateral cerebellar dysfunction cause?
Slowed, slurred speech (dysarthria)
Bilateral inco-ordination of arms
Staggering, wide-based gait (cerebellar ataxia)
What are the functions of the basal ganglia?
Facilitate purposeful movement
Inhibit unwanted movements
Posture and muscle tone
What are the basal ganglia?
A number of masses of grey matter found at the base of each cerebral hemisphere
What are the 5 basal ganglia?
Caudate nucleus Putamen Globus pallidus Subthalamic nucleus Substantia nigra
What makes up the lenticular nucleus?
Putamen
Globus pallidus
What makes up the striatum?
Caudate nucleus
Putamen
What makes up the corpus striatum?
Caudate nucleus
Putamen
Globus pallidus
Where is the amydala situated?
On the end of the caudate nucleus
Where is the substantia nigra found?
Midbrain
Why is the substangia nigra black?
Dopaminergic neurones
How do basal ganglia affect normal movement?
They enhance it
What is meant by the direct pathway of basal ganglia?
Net effect of exciting thalamic neurones
What is meant by the indirect pathway of basal ganglia?
Net effect of inhibiting thalamic neurones i.e. stops unwanted muscle contractions from competing with voluntary movements
What would a unilateral lesion of basal ganglia cause?
Affects the CONTRALATERAL side
Change in muscle tone
Dyskinesias e.g. tremor, chorea, myoclonus
What diseases affect basal ganglia?
Parkinsons
Huntingtons
