7) Parkinsons

Question 1

What are the 4 main characteristics of Parkinson’s?

Answer 1

Asymmetrical resting tremor
Bradtkinesia
Rigidity
Postural instability

Question 2

Parkinson’s affects 1 in 100 people over the age of what?

Answer 2

65, more than the combined incidence of MS, ALS and muscular dystrophy

Question 3

It affects what gender more?

Answer 3

2 males: 1 female

Question 4

What two bad habits is the development of Parkinson’s inversely correlated to?

Answer 4

Smoking

Caffeine consumption

Question 5

What is the general describer of Parkinson’s?

Answer 5

Idiopathic, neurodegenerative caused by the loss of dopaminergic neurons in the substantia nigra

Question 6

Describe synaptic transmission.

Answer 6

An influx of sodium causing depolarization produces an action potential that propagates to the presynaptic terminal where it opens Ca channels.
The Ca influx causes the exocytosis of neurotransmitters, which enter the synaptic cleft binding to the post synaptic membrane.

Question 7

Tyrosine is taken up by the brains extracellularly fluid in the dopaminergic substantia nigra neurons. What two forms does it take on?

Answer 7

Tyrosine is hydroxylated to become L-Dopa

L-DOPA is decarboxylated to become dopamine

Question 8

What part of the brain controls movements?

Answer 8

Basal ganglia

Question 9

What is the basal ganglia composed of?

Answer 9

Substantia nigra
Striatum
Subthalamic nucleus

Question 10

Input from all over the brain is sent through dopaminergic neurons where?

Answer 10

Striatum

Question 11

What is the striatum composed of?

Answer 11

Putamen

Caudate nucleus

Question 12

This part of the striatum has D1 and D2 neuron receptors.

Answer 12

Putamen neurons

Question 13

What does the ventrolateral thalamus do?

Answer 13

Initiates body movement.

Question 14

The sub thalamic nucleus is inhibitory in the motor pathway, what does it connect?

Answer 14

Striatum and VLT

Question 15

The 3 main neurotransmitters in Parkinson’s disease are:

Answer 15

Dopamine (excitatory)
GABA (inhibitory)
Acetylcholine (inhibitory)

Question 16

How does dopamine work?

Answer 16

Through the direct and indirect pathway in the basal ganglia to initiate voluntary movement.

Question 17

When does Parkinson’s manifest itself in relation to dopamine biosynthesis?

Answer 17

When ~80% of dopamine function has been lost.

Question 18

What does too much acetylcholine cause?

Answer 18

The antagonistic neurotransmitter causes over activity of cholinergic neurons, leading to muscle contractions that won’t repolarize.

Question 19

This neurotransmitter is the main inhibitory neurotransmitter.

Answer 19

GABA

Question 20

What is the normal release of GABA regulated by and what will a reduction in the regulator cause?

Answer 20

It is regulated by binding to dopamine receptors and a reduction in dopamine causes an increase in GABA, resulting in full or partial paralysis.

Question 21

What stimulates dopamine synthesis?

Answer 21

Substantia nigra

Question 22

Dopamine binds to what to receptors on the putamen neurons in the striatum?

Answer 22

D1 (direct pathway) and D2 (indirect pathway)

Question 23

Dopamine binding to the D1 receptors of Substance P producing putamen neurons causes an increase in what neurotransmitter and what’s its affect?

Answer 23

GABA is increased which inhibit the neuron firing of D1 putamen neurons.

Question 24

D1 putamen neuron firing inhibits what, and when an increase of GABA occurs inhibiting D1 firing what is the result?

Answer 24

VLT

Increase of GABA, Decrease in D1 firing= less inhibition of VLT= signals sent to motor cortices leading to movement.

Question 25

Both direct and indirect pathways produce movement by decreasing the inhibition of what?

Answer 25

VLT

Question 26

Describe the direct pathway of Parkinson's.

Answer 26

A deficiency in dopamine leads to inactivated D1 receptors, therefore substance P is not released leading to a decrease in GABA. D1 firing is increased which release GABA inhibiting the VLT to send signal to the motor cortex. =inability to move

Question 27

This Parkinson's is characterized by a degeneration of pigmented dopaminergic neurons in the Substantia Nigra, with the remaining dopaminergic neurons containing Lewy Bodies.

Answer 27

Idiopathic Parkinson's Disease | Primary Parkinson's

Question 28

What are the two possible factors in developing Parkinson's?

Answer 28

Genetics Oxidative stress Excitotoxicity

Question 29

The Substantia nigra is a region characterized by high levels of oxidative stress, which means what?

Answer 29

The free radicals generated by dopamine metabolism attacks and damage neurons because the normal antioxidants are not there

Question 30

Secondary parkinsonism signs may be due to what 3 issues?

Answer 30

Inability for dopamine to be produced, secreted or bind to the post synaptic putamen receptors.

Question 31

What are the 4 causes of secondary Parkinson's?

Answer 31

Drugs Toxins Infection Head trauma

Question 32

The onset of this secondary Parkinson's is abrupt and symmetrical, caused by dopamine antagonists blocking the dopamine receptors

Answer 32

Drug induced Parkinsonism | Antipsychotics and Ca channel blockers

Question 33

Pesticides and heavy metals can cause irreversible damage to the dopaminergic ions in the substantia nigra

Answer 33

Toxin induced Parkinson's

Question 34

The degeneration of nerve cells in the substantia nigra following encephalitis, leaving the patient speechless and statue like

Answer 34

Post-encephalitic syndrome | Infection

Question 35

Lesions to the substantia nigra cause hematoma, creating pressure and obstructing ventricular outflow affecting the dopaminergic cells.

Answer 35

Trauma induced | Head trauma

Question 36

What is the threshold for clinically detectable Parkinson's?

Answer 36

70-80% of the dopaminergic neurons in the substantia nigra have been lost

Question 37

This primary symptom is common in 2/3 of patients, normally starting unilaterally and becoming bilateral, with severity and amplitude increasing under stress

Answer 37

Resting tremor

Question 38

Slowness and discontinuous movement, with freezing in place occurring.

Answer 38

Bradykinesia

Question 39

Increased rigidity in passive movement, that begins unilaterally and develops into bilateral

Answer 39

Cogwheel rigidity

Question 40

A stooped posture that increases the risk of falling, found in the more advanced stages of Parkinson's

Answer 40

Postural instability

Question 41

What are the two types of secondary symptoms a person may experience?

Answer 41

Motor | Autonomic

Question 42

What are the results of motor symptoms.

Answer 42

``` ○Decrease in spontaneous blink rate ○ Hypomimia (no facial expression) ○ Monotonous voice ○ Speech hurried, slurred ○ Micrographia (tiny writing) ○ Drooling ```

Question 43

What are the results of the autonomic symptoms?

Answer 43

``` ○ Uncontrolled sweating ○ Excess salivation (drooling) ○ Lacrimation (crying) ○ Impaired thermal regulation ○ Constipation ○ Urinary incontinence ○ Impotence ○ Sexual dysfunction ```

Question 44

What are 5 psychological symptoms experienced with Parkinsons?

Answer 44

``` Dementia Anxiety Depression Psychosis Sleep disturbances ```

Question 45

Describe Huntington's disease?

Answer 45

It is an autosomal dominant neurodegenerative condition that causes hyperkinetic movement, with the age of onset between 30-50 years

Question 46

How is diagnosing for Parkinson's done?

Answer 46

There is no diagnostic test as of yet. | It is done by medical examination and a full clinical history to rule out secondary Parkinsonism.

Question 47

Clinically probable IPD can be diagnosed when the patient shows 2 of the following symptoms:

Answer 47

● Muscle rigidity ● Bradykinesia ● Resting tremor ● Postural instability

Question 48

The only true confirmation of Parkinson's comes after death. Why?

Answer 48

Autopsy reveals presence of Lewy bodies in | the Substantia Nigra