John Peters:- An introduction to Pain slide 11

Question 1

What innervates skeletal muscle?

Answer 1

Motor neurones

Question 2

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

Answer 2

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

Question 3

What is the neurotransmitter found at the terminal boutons ?

Answer 3

Acetylcholine

Question 4

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

Answer 4

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

Question 5

Where woud you find nicotinic acetlycholine receptors?

Answer 5

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

Question 6

What happens at the neuromuscular junction?

Answer 6

Action potential

Ca2+ channels open and calcium rushes in

Depolarization

Acetlycholine is released

Acetlycholine is broken down

Choline is returned to the cell

Question 7

What breaks down Acetlycholine?

Answer 7

Acetylcholinesterase

Question 8

What is acetylcholine broken down into?

Answer 8

Acetate and Choline

Question 9

How is choline transported in to the bouton?

Answer 9

Alongside Na+

Question 10

Where is Acetlycholine synthesised?

Answer 10

in the Cytosol

Question 11

What is the reaction to make Acetlycholine?

Answer 11

Choline + acetyl coenzyme A = Acetylcholine

Question 12

What enzyme is required to make acetylcholine?

Answer 12

Choline acetyltransferase

Question 13

What concentrates acetylcholine in vesicles?

Answer 13

Vesicular ACh transporter

Question 14

What happens in the post-synaptic process?

Answer 14

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

Question 15

What is a “quantum”?

Answer 15

A quantum is the amount of neurotransmitter contained in one vesicle

Question 16

What does a quantum of acetlycholine cause?

Answer 16

a miniature endplate potential

Question 17

What is the “all or none” theory?

Answer 17

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.

Question 18

What does the end plate potential do?

Answer 18

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

Question 19

How does the action potential make the muscle contract?

Answer 19

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

Question 20

What happens in Myasthenia Gravis?

Answer 20

Autoimmune destruction of nicotinic acetylcholine receptors in the endplate.

Question 21

What does Botulinum Toxin do?

Answer 21

Irreversibly inhibits Ach release

Question 22

What is Neuromytonia also known as ?

Answer 22

Isaac’s syndrome

Question 23

What is Neuromyonia?

Answer 23

Autoimmune hyperexcitabilty of volatge activated K+ channels

Question 24

Define Pain?

Answer 24

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

Question 25

What are the three forms of pain?

Answer 25

Nociceptive pain

Inflammatory Pain

Pathological pain

Question 26

What are Nociceptors?

Answer 26

Peripheral primary sensory afferent neurones which are activated by intesne noxious stimuli

Question 27

What are the two characterisitcs of Nociceptive pain?

Answer 27

It is adaptive

It has a high thershold

Question 28

What does the Nocieptive Pain actually do?

Answer 28

It is responsible for the withdrawal reflex

Question 29

What does inflammatory pain do?

Answer 29

It causes pain hypersensitvity

and

Allodynia (Innocuous stimuli now causes pain)

Question 30

Why is inflammatory pain necessary?

Answer 30

Assits in wound healing by:

Discouraing physical contact

Discouraging movement

Question 31

What is Pathaological pain?

Answer 31

Maladaptive pain with no protective function

Question 32

How is pain like a burgelar alarm?

Answer 32

Nociceptive pain - oh shit its begby, run

Inflamatory pain - Whats that noise… its probably begby

Pathological pain - False alarms all the time

Question 33

What are the two types of Nociceptors?

Answer 33

A-fibres

C-fibres

Question 34

How do the two types of Nociceptors differ?

Answer 34

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