Muscular Problems & Neuromuscular Junction Flashcards

1
Q

What are the properties of a muscle affected by LMN disorders?

A
  • Weak
  • Has low tone
  • Has fasiculations
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2
Q

What are fasiculations?

A
  • Visible, fast, spontaneous twitches occurring in denervated muscle
  • May occur in healthy muscle
  • A sign of motor neurone disease
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3
Q

What is the three step process to make muscles contract?

A

Motor neurone - Neuromuscular junction - Muscle

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4
Q

Where do lower motor neurone cell bodies arise?

A

Ventral horn of the spinal cord

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5
Q

What is the definition of a motor end plate?

A

The synapse formed between motor neurons and muscles

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6
Q

What substance is toxic IV/IM because it occupies the same position on ACh receptors but does not open the ion channels?

A

Curare

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7
Q

What does botulinum toxin do?

A

Cleaves presynaptic proteins involved in vesicle formation and blocks docking with presynaptic membranes

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8
Q

What occurs in Lambert Eaton Myasthenic syndrome?

A

Auto-antibodies to presynaptic calcium channels leads to decreased vesicle release

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9
Q

What occurs in Myasthenia Gravis?

A

Autoimmune reaction to acetylcholine receptors which leads to muscle weakness and fatiguability (when ACh receptors reduced to

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10
Q

What also plays a role in MG?

A

The thymus - 75% of patients have hyperplasia or thymoma

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11
Q

How is MG treated?

A
  • Acetylcholinesterase inhibitor (pyridostigmine)
  • Thymectomy
  • Steroids
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12
Q

What is myotonia?

A

Failure of muscle to relax following use

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