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Question 1

Describe the cerebellum

Answer 1

Highly folded and convolutedGrey matter cortexWhite matter core

Question 2

What are the three functional zones of the cerebellum?

Answer 2

VestibulocerebellumSpinocerebellumCerebrocerebellum

Question 3

Describe the vestibulocerebellum

Answer 3

Input from vestibular system- balance and ocular reflexes

Question 4

Describe the spinocerebellum

Answer 4

Input from spinocerebellar tract- unconcious proprioception and error correction

Question 5

Describe the cerebrocerebellum

Answer 5

Input from contralateral cerebral cortex- fine motor control- movement planning- motor learning

Question 6

What are some general signs that are associated with cerebellar dysfunction?

Answer 6

Incoordination of movementAtaxic gaitAtaxic, dysarthritic speechAbnormal eye movementsHyptonia

Question 7

Define dysmetria

Answer 7

Inability to control smooth and accurate targeted movements- jerky movements- overshooting target- finger-nose or heel-shin test

Question 8

Describe ataxic gait

Answer 8

Staggering gait, may become wide-based later on- mild cases may only be seen when getting the patient to walk heel to toe

Question 9

What kind of abnormal eye movements do you see with cerebellar dysfunction?

Answer 9

coarse nystagmus- more pronounced when looking towards side of lesion

Question 10

Describe the rebound phenomenon

Answer 10

Push down on outstretched arms of the Pt the abruptly release. Arms will rebound upwards further than expected.

Question 11

Define the basal ganglia

Answer 11

A collection of subcortical nuclei

Question 12

What structures make up the basal ganglia?

Answer 12

Caudate nucleusPutamenGlobus pallidusSubstantia nigraSubthalamic nucleus

Question 13

What is the neostriatum?

Answer 13

Made up from the caudate nucleus and the putamen

Question 14

What id the lenticular nucleus?

Answer 14

The putamen and the globus pallidus

Question 15

What is the role of the basal ganglia?

Answer 15

Regulates the amplitude and velocity of the planned movement, particularly in relation to the use of proprioceptive information.

Question 16

What does the basal ganglia do at rest?

Answer 16

Actively inhibits movement

Question 17

Describe the process of what the basal ganglia does at rest.

Answer 17

• Cerebral cortex does not stimulate striatum- Globus pallidus interna inhibits the thalamus- Thalamus cannot stimulate the cerebral cortex- Less stimulation of the cerebral cortex gives less movement

Question 18

What does the direct pathway of the basal ganglia do?

Answer 18

Amplifies planned movements

Question 19

Describe the process of the direct pathway of the basal ganglia

Answer 19

• Cerebral cortex stimulates the striatum- Striatum inhibits the globus pallidus interna- GPi inhibition removes thalamus inhibition- Thalamus stimulate the cerebral cortex and increases stimulus of movements via upper motor neurones

Question 20

What does the indirect pathway of the basal ganglia do?

Answer 20

Dampens down planned movements- takes longer than direct pathway, so acts after it

Question 21

Describe the process of the indirect pathway of the basal ganglia

Answer 21

• Cerebral cortex stimulates striatum- Striatum inhibits globus pallidus externa- GPe removes inhibition from the subthalamic nucleus- Subthalamic nucleus stimulates the GPi- GPi stimulates inhibition of the thalamus- Thalamus cannot stimulate the cerebral cortex- Lees stimulation leads to less movement due to less stimulation of UMNs form the cerebral cortex

Question 22

What does the substantia nigra compacta do?

Answer 22

Amplifies direct and inhibits indirect basal ganglia pathways. Causes an increases amplification of movements.

Question 23

How does the substantia nigra compacta bring about its action?

Answer 23

• Dopaminergic neurones form the SNC act on the striatum- D1 = increase GPi inhibition- D2 = decrease GPe inhibition

Question 24

What types of movement will be generated in basal ganglia dysfunction?

Answer 24

HypokineticHyperkinetic

Question 25

Describe Parkinson’s Disease

Answer 25

Hypokinetic disorderDue to progressive degeneration of dopaminergic neurones that run between the substantial nigra and the striatum

Question 26

What are the symptoms that are seen in Parkinsons?

Answer 26

1. tremor at rest2. hypertonia3. bradykinesiaParkinsonian gait - stooped posture, with shuffling steps and pedestal turning

Question 27

When do symptoms of Parkinson’s disease appear?

Answer 27

Older then 60 yearsOnce 75-80% of dopaminergic neurones have degeneratedWill have had the disease for a number of years before symptoms appear

Question 28

What changes occur in the basal ganglia in Parkinson s disease?

Answer 28

• Death of dopaminergic neurones in substantia nigra- Less dopamine at D1 receptors (increase inhibition of thalamus)- Less dopamine at D2 receptors (increased inhibition of thalamus)- Suppression of direct pathway0- Amplification of indirect pathway- Increase thalamus inhibition which leads to less stimulation of the cerebral cortex- Less output leads to hypokinesia

Question 29

Describe Huntington’s Chorea

Answer 29

Autosomal dominant genetic diseaseCauses jerky, involuntary movements as well as the progressive development of psychiatric and cognitiv symptoms.

Question 30

What causes Huntingtons?

Answer 30

Gene mutation in Huntingtin protein. Causes aggreagates adn leads to cell death.

Question 31

What changes are seen in Huntingtons?

Answer 31

Neuronal loss in the caudate nucleusReduction in GABA and AchLoss os inhibitor synaptic transmission which leads to decreased thalamic inhibtion and therefore an increase in stimulation of movement via the cerebral cortex.

Question 32

What happens with sympathetic innervation to the bladder?

Answer 32

Stimulation by the hypogastric nerve (T10-L2) will cause:- detrusor relaxation (NA at B3)- contraction of internal urethral sphincter (NA at A1)

Question 33

What happens with parasympathetic innervation to the bladder?

Answer 33

Stimulation by the pelvic nerve (S2-S4) releases ACh which acts on M3 receptors to cause contraction of the detrusor muscle.

Question 34

What stimulates the change form the sympathetic to parasympathetic stimulation?

Answer 34

Activation of afferent stretch receptors (S2-S4) once the bladder reaches 400ml

Question 35

How does micturition occur?

Answer 35

Removal of sympathetic stimulation causes relaxation of internal urethral sphincter whilst increase parasympathetic stimulation causes contraction of the detrusor muscle. The brain then makes the conscious decision to urinate, which stimulates relaxation of the external urethral sphincter via the pudendal nerve (S2-S4).

Question 36

How does the brain bring about urination?

Answer 36

Brain micturition centre stimulate the spinal micturition centre to increase the parasympathetic stimulation.

Question 37

Describe pure pyramidal UMN signs

Answer 37

Loss of spinal cord excitation by the motor cortex (corticospinal and corticobulbar)- hypotonia- loss of fractionation of finger movementsVERY RAREunlikely to sever only one tract

Question 38

Describe extra-pyramidal UMN signs

Answer 38

Extrapyramidal tracts are responsible for mediation descending inhibition of LMN- hypertonia due to inability to mediate movement by descending inhibition.