9: Physiology - Pain and thermosensation Flashcards Preview

Neurology Week 2 2018/19 > 9: Physiology - Pain and thermosensation > Flashcards

Flashcards in 9: Physiology - Pain and thermosensation Deck (39)
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1

What is pain?

Unpleasant sensory / emotional experience

Associated with tissue damage or described in terms of it

2

Does pain mean that tissue damage is occurring?

Not neccessarily

3

Which type of pain is a short-term response to prevent tissue damage?

Nociceptive pain

4

What is the purpose of inflammatory pain?

Stops you from touching a damaged area until healing has occurred

5

How long does inflammatory pain persist for?

Days - Weeks

6

What are some adjuvant drugs which can be used to control pain?

Antidepressants

Anticonvulsants

Local anaesthetics

7

Describe pain originating from the skin.

WELL LOCALISED

stabbing, pricking, burning

8

Pain originating from the muscle and viscera tend to be ___ localised.

poorly localised

9

Visceral pain tends to be ___.

Muscle pain tends to be ___.

dull

achey

10

Pain can be ___ to distant areas.

referred

11

Which receptors detect intense stimuli to cause the sensation of pain?

Nociceptors

12

What sort of stimulus triggers a nociceptor?

High intensity stimuli

of a THERMAL, MECHANICAL or CHEMICAL nature

13

Nociceptors are which order neurons?

FIrst order neurons

14

What are the factors influencing the conduction velocity of a neuron?

1. Myelination

2. Diameter of axon

15

Which type of sensory fibre transmits fast pain?

A-delta

look back at the table of conduction velocities

16

Which type of sensory fibre transmits slow pain?

C fibres

look back at table of conduction velocities

17

What does

a) fast pain

b) slow pain

feel like?

a) Stabbing, pricking, burning

b) Aching, throbbing

18

Which ions enter a neuron to cause a depolarisation?

Na+

Ca2+

19

Why does injured tissue feel hot?

One of the TRP channels responsible for noxious heat is activated

20

What does polymodal mean in terms of nociceptors?

Respond to more than one noxious stimulus

21

At which specific temperature does warmth become unpleasant heat?

43 degrees Celsius

22

Which two types of nerve fibre make up most nociceptors?

A-delta ('fast' pain fibre)

('slow' pain fibre)

23

Which neurotransmitters are involved in the transmission of pain signals?

Glutamate

(excitatory)

24

The more a synapse is activated, the more ___ it becomes.

efficient

25

What is released at the peripheral terminal of a nociceptor when it is activated?

Inflammatory mediators

26

What causes sterile neurogenic inflammation?

Release of inflammatory mediators from the PERIPHERAL terminal of activated nociceptors

27

Which neurotransmitter is released into the synaptic cleft when a pre-synaptic sensory fibre is activated?

Which change in membrane potential does it cause?

Glutamate

Depolarisation (excitatory post-synaptic potential)

28

Two ligands, AMPA and NMDA, bind to receptors to change the type of excitatory post-synaptic potential that is produced.

What does each cause?

AMPA - fast

NMDA - slow

29

The excitatory post-synaptic potential causes a depolarisation which overcomes threshold potential.

What happens next?

Action potential

30

What does repeated stimulation of a synapse cause in the long term?

Increased efficiency

giving rise to hyperalgesia and allodynia