Disorders of nervous system Flashcards

(51 cards)

1
Q

What is the definition of a neurodegenerative disease?

A

Disorder in which particular neurons degenerate leading to loss of function of that region of the central or peripheral nervous system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are some neurodegenerative diseases?

A

Alzheimer’s
Parkinson’s
Huntington’s
Sclerosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the main neurons lost in Alzheimer’s?

A

Cholinergic neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the first part of the brain usually affected by Alzheimers?

A

Hippocampus and then spreads to frontal lobe (communication) and parietal (orientation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are plaques of Alzheimers made of ?

A

extracellular deposits of degenerating nerve processes and a core of insoluble beta-amyloid proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are neurofibrillary tangles?

A

In Alzheimers disease, they are found in cell bodies and axons and are composed of hyperphosphorylated protein tau, which is involved in assembly of microtubules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the genetic factors involved in Alzheimers ?

A

Mutations of the genes encoding amyloid precursor protein (APP) and presenilin (involved in processing amyloid )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are possible environmental factors involved in Alzheimers?

A

high levels of aluminium in soil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where is APP usually found?

A

Membrane of neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What enzyme cleaves APP into fragments?

A

Secretase enzyme (alpha,beta,gamma). Presenilin is catalytic component of gamma-secretase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What fragment of APP is particularly toxic to neurons?

A

A(beta)42

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the current drugs used for Alzheimers?

A

Acetylcholineesterase inhibitors that prevent breakdown of ACh, or ACh receptor agonist that mimic ACh and alleviate symptoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are future possibilities for Alzheimers treatment?

A

Inhibition of secretase enzyme

Antibody-base drugs designed to target toxic Abeta

Vaccine to improve immunity to toxic Abeta

Stem cells to replace lost neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What causes Parkinson’s disease?

A

The degeneration of dopaminergic neutrons of the nigrostriatal pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is one of the features of Parkinson’s?

A

The accumulation of dense deposits (Lewy bodies) in the nigrostriatal neurons that impair their function or destroy them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the nigrostriatal pathway?

A

Neurons that project from the substantia ingrate to the striatum (basal ganglia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What could be an environmental factor for Parkinson’s?

A

Exposure to MPTP which is oxidised by the monoamine oxidase found in dopaminergic neurons, into MPP+ . This then binds to Neuromelanin and inhibits etc killing the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the genes involved in Parkinson’s?

A

SNCA gene (park1) which encodes alpha-synuclein and PARK2 gene that encodes the protein parkin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the role of alpha-synuclein ?

A

It is a nerve terminal protein and a toxic form of it is found in Lewy bodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the role of Parkin?

A

An enzyme component of ubiquitin-proteasome pathway responsible for removal of damaged proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the treatments for Parkinson’s?

A
  • L-DOPA , precursor of dopamine
  • Inhibitors of enzyme monoamine oxidase which degrades dopamine
  • DEEP BRAIN STIMULATION: surgical procedure where electrons are implanted in the brain and connected to a stimulator places somewhere else in the body. These impulses override the abnormal electrical signals caused by the disease
22
Q

What is the most common demyelinating disorder?

A

Multiple sclerosis

23
Q

Is MS acquired or inherited?

24
Q

What are some possible causes of MS?

A
  • Infectious agent: Epstein-Barr virus mostly
  • Immune-mediated: antibodies produced against myelin components (molecular mimicry)
  • Genetic Factors: mostly genes involved in MHC
25
How is MS diagnosed?
1. Nerve conduction test (record speed of electrical conduction) 2. Sampling of CSF by lumbar puncture for presence of white blood cells or antibodies 3. Magnetic Resonance Imaging to look for abnormalities and scarring in white matter
26
How is MS treated?
Drugs like β-interferons that alleviate symptoms and progression by acting at the Level of immune system Exercise, physiotherapy and diet
27
Is Guillan-Barrè syndrome acute or chronic?
Acute
28
What is another name for Guillan-Barrè syndrome ?
Acute inflammatory demyelinating polyneuropathy
29
What neurons does Guillan-Barrè affect?
Somatic motor (paralysis and respiratory problems) Sensory neurons (loss of sensation) Autonomic neurons ( blood pressure and cardiac arrhythmia)
30
How does Guillan-Barrè happen?
When antibodies triggered by a viral infection attack components of Schwann cell myelin
31
What is a treatment for Guillan-Barrè ?
Immunoglobulins intravenously and plasmapheresis (plasma exchange)
32
Is Charcot-Marie-Tooth Disease inherited ?
Yes
33
In which way is CMT usually inherited?
Autosomal (dom/rec.) in 80-90% of cases
34
What is the main gene affected in autosomal cases of CMT?
Peripheral myelin protein-22 (PMP-22) involved in development and maintenance of Schwann cell myelin Rare cases due to mutations in myelin protein zero (P0) gene which encodes an adhesion molecule important for compaction of PNS myelin
35
What is the main gene affected in cases of CMTX?
Mutation in gene connexion 32 which encodes the channel proteins of gap junctions
36
Where is Cx32 found?
Schwann cells
37
What does Cx32 do?
Forms reflexive gap junctions between the layers of myelin membrane surrounding peripheral axons
38
What are symptoms of myasthenia disorders?
Weakness and fatiguability affecting ocular, facial, bulbar, respiratory and limb muscles
39
How do myasthenic disorders arise?
From defects in any of the components of synaptic transmission and may arise from autoimmune or genetic basis
40
Two examples of autoimmune myasthenic disorders?
Myasthenia gravis (MG) and Lambert-Eaton Myasthenia (LEMS)
41
What happens in MG?
Auto-antibodies attack protein subunits of nicotinic ACh receptor
42
Is MG presynaptic or postsynaptic defect?
Postsynaptic
43
How does MG affect nicotinic ACh receptor?
Autoantibodies either block transmitter binding, increase the rate of receptor degradation or destroy the postsynaptic membrane leading to cell lysis
44
What happens in LEMS?
Antibodies attack voltage gated Ca++ channels in the motor neuron presynaptic terminal, reducing ACh release as Ca++ is trigger for exocytosis
45
Is LEMS presynaptic or postsynaptic defect?
Presynaptic
46
Examples of Congenital myasthenic syndromes
1. Ach Receptor deficiency 2. Congenital myasthenic syndrome with Episodic apnea (CMSEA) 3. End plate Acetylcholinesterase deficiency
47
What happens in ACh receptor deficiency ?
Mutations in genes that encode subunits of nicotinic ACh receptor leading to fewer receptors or with altered properties (POSTSYNAPTIC)
48
What happens in Congenital myasthenic syndrome with Episodic apnea (CMSEA)?
Mutations in choline acetyltransferase, the ACh synthetic enzyme leading to insufficient production of neurotransmitters (PRESYNAPTIC)
49
What happens in End Plate Acetylcholinesterase Deficiency?
Mutations in acetylcholinetransfferase, the ACh degradative enzyme leading to insufficient production of neurotransmitter (SYNAPTIC DEFECT)
50
What can LEMS be associated with?
Lung cancer or other cancers because of cell mimicry
51
What are some symptoms of CMT?
- motor deficits (weakness of leg, foot and hand muscles) | - sensory loss ( unable to perceive temperature, pain..)