John Peters:- An introduction to Pain slide 11 Flashcards

1
Q

What innervates skeletal muscle?

A

Motor neurones

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2
Q

What happens to the motor neuron when it is nearing its muscle?

A

It loses its myelen sheaf and splits up into different branches all having their own terminal button forming a chemical synapse

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3
Q

What is the neurotransmitter found at the terminal boutons ?

A

Acetylcholine

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4
Q

What are the four key features of the skeletal neuromuscular junction?

A
  1. Terminal bouton and schwann cell
  2. Synapic vesicles
  3. Synaptic cleft
  4. End plate region
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5
Q

Where woud you find nicotinic acetlycholine receptors?

A

At region of the junctional folds of the end plate region that face the active zones

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6
Q

What happens at the neuromuscular junction?

A

Action potential

Ca2+ channels open and calcium rushes in

Depolarization

Acetlycholine is released

Acetlycholine is broken down

Choline is returned to the cell

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7
Q

What breaks down Acetlycholine?

A

Acetylcholinesterase

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8
Q

What is acetylcholine broken down into?

A

Acetate and Choline

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9
Q

How is choline transported in to the bouton?

A

Alongside Na+

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10
Q

Where is Acetlycholine synthesised?

A

in the Cytosol

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11
Q

What is the reaction to make Acetlycholine?

A

Choline + acetyl coenzyme A = Acetylcholine

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12
Q

What enzyme is required to make acetylcholine?

A

Choline acetyltransferase

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13
Q

What concentrates acetylcholine in vesicles?

A

Vesicular ACh transporter

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14
Q

What happens in the post-synaptic process?

A

2 actelycholine molecules bind

Channel opens for cations only

Na+ influx and K+ eflux

Infflux of sodium is greater than efflux of potassium resulting in deporelization

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15
Q

What is a “quantum”?

A

A quantum is the amount of neurotransmitter contained in one vesicle

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16
Q

What does a quantum of acetlycholine cause?

A

a miniature endplate potential

17
Q

What is the “all or none” theory?

A

You need a certain nummber of M.E.P.P in quick succession in order to produce one muscle action potential

The E.P.P must exceed the therhold.

18
Q

What does the end plate potential do?

A

Triggers the opening of voltage activated sodium channels causing a muscle action potential

19
Q

How does the action potential make the muscle contract?

A

Action potential travels down the T-tubules triggering the release of calcium ions which interact with troponin associated with the myofibrils

20
Q

What happens in Myasthenia Gravis?

A

Autoimmune destruction of nicotinic acetylcholine receptors in the endplate.

21
Q

What does Botulinum Toxin do?

A

Irreversibly inhibits Ach release

22
Q

What is Neuromytonia also known as ?

A

Isaac’s syndrome

23
Q

What is Neuromyonia?

A

Autoimmune hyperexcitabilty of volatge activated K+ channels

24
Q

Define Pain?

A

An unspleasent sensory and emotional experiance, associated with actual tissue damage or described in terms of such damage

25
What are the three forms of pain?
Nociceptive pain Inflammatory Pain Pathological pain
26
What are Nociceptors?
Peripheral primary sensory afferent neurones which are activated by intesne noxious stimuli
27
What are the two characterisitcs of Nociceptive pain?
It is adaptive It has a high thershold
28
What does the Nocieptive Pain actually do?
It is responsible for the withdrawal reflex
29
What does inflammatory pain do?
It causes pain hypersensitvity and Allodynia (Innocuous stimuli now causes pain)
30
Why is inflammatory pain necessary?
Assits in wound healing by: Discouraing physical contact Discouraging movement
31
What is Pathaological pain?
Maladaptive pain with no protective function
32
How is pain like a burgelar alarm?
Nociceptive pain - oh shit its begby, run Inflamatory pain - Whats that noise... its probably begby Pathological pain - False alarms all the time
33
What are the two types of Nociceptors?
A-fibres C-fibres
34
How do the two types of Nociceptors differ?
A-fibres are myelinated and respond fast but only to mechanical or thermal injury C-fibres are unmyelinated so respond slower but can respond to all sources of pain
35