N11- Pain and nociception

Question 1

Name some causes of pain in dentistry.

Answer 1

• dentine sensitivity
• caries
• trauma
• cracked cusp
• dry socket
• salivary gland pain
• sinusitis

Question 2

what is the sensation of nociception and what are its non-sensory effects?

Answer 2

sensation: Pain

non-sensory effects: protective reflexes,cardiovascular reflexes and alertness

Question 3

what is the sensation of thermoreception and what are its non-sensory effects?

Answer 3

sensation- hot/cold

non-sensory- thermoregulatory reflexes,, sweating, shivering

Question 4

what is the sensation of mechanoreception and what are its non-sensory effects?

Answer 4

sensation- touch

non-sensory effects- stretch/protective/salivary reflexes

Question 5

what is the sensation of proprioception and what are its non-sensory effects?

Answer 5

sensation- position sense

non-sensory effects- stretch reflexes

Question 6

what is the sensation of gustation and what are its non-sensory effects?

Answer 6

sensation- taste

non-sensory effects- salivary reflexes

Question 7

what is the sensation of olfaction?

Answer 7

sensation- smell

Question 8

what is the definition of pain?

Answer 8

an unpleasant sensory and emotional experience associated with actual or potential tissue damage

Question 9

what is the definition of nociception?

Answer 9

the activation of neural pathways by stimuli that damage or threaten to damage tissues

Question 10

what is a noxious stimulus?

Answer 10

potentially damaging stimulus

Question 11

what is a nociceptive stimulus?

Answer 11

a stimulus that activates nociceptive pathways (in research)

Question 12

what does pain normally signify?

Answer 12

• caries
• abscess
• TMJ
• fracture

Question 13

what is the name for pain in healthy areas?

Answer 13

referred pain

Question 14

Name a significant pathology that is not painful.

Answer 14

tumours

Question 15

why is pain useful?

Answer 15

• avoid further damage

- future avoidance

Question 16

what is the name when you don’t feel pain?

Answer 16

congenital insensitivity to pain

Question 17

what are the 2 types of pain?

Answer 17

acute- fast, sharp pain

chronic- slow, burning pain

Question 18

what are the 2 dimensions of pain?

Answer 18

Sensory-discrimitve - quality, intensity and location

Affective- emotional aspects

Question 19

How do you study pain on animal models?

Answer 19

-Nociception - electrophysiological recordings
– behavioural responses – e.g. vocalisation
– reflex studies

Question 20

how do you study pain on humans?

Answer 20

– microneurography
– psychophysical studies – blister studies
– reflex studies

Question 21

what are nociceptors?

Answer 21

receptors that respond to noxious/nociceptive stimuli

Question 22

what are nociceptors classified by?

Answer 22

• parent axon

- stimulus

Question 23

Describe the structure of the axons in nociceptors.

Answer 23

• C-fibre- fine and unmyelianted, diameter 0.2 to 1.5microm, conduction velocity 0.2-2ms
• Ad fibre- fine myelinated, diameter 1-5micrometeres, conduction velocity 5-30ms

Question 24

what axon is for fast and sharp pain?

Answer 24

Ad fibres

Question 25

what axon is for slow and burning pain?

Answer 25

C fibres

Question 26

what do Ad mechanical nociceptors respond to?

Answer 26

strong mechanical stimuli

Question 27

what do Ad polymodal nociceptors respond to?

Answer 27

all types of noxious stimuli

Question 28

what type of nociceptors is C-fibre?

Answer 28

polymodal

Question 29

Describe direct nociceptor transduction.

Answer 29

Stimulus acts directly
– Mechanical, Chemical and thermal
-Membrane permeability changes - Graded potential

Question 30

Describe indirect nociceptor transduction.

Answer 30

• Tissue injury / inflammation

- Chemicals released -> nerve ending

Question 31

Describe mechanical nociceptor transduction.

Answer 31

• Stimuli: pinch, pressure

- Mechanically sensitive ion channels

Question 32

Describe thermal nociceptor transduction.

Answer 32

Vanilloid Receptors:
– >45°C: TRPV1
– >50°C: TRPV2 receptor

Question 33

what gives the sensation of warmth?

Answer 33

capsaicin

Question 34

what does capsaicin activate?

Answer 34

TRPV1 at <45°C – Spicy foods (chilli peppers)

Question 35

what activates nocicptive nerve ending?

Answer 35

• ATP
• H+
• K+

Question 36

what activates or sensitize nociceptive nerve endings?

Answer 36

• bradykinin
• histamine
• serotonin (5-HT)

Question 37

what sensitizes nociceptive nerve endings?

Answer 37

prostaglandins

Question 38

what chemicals are released from nerve endings?

Answer 38

substance P

Question 39

where is substance P present?

Answer 39

fine peripheral fibres

Question 40

substance p has a role in what?

Answer 40

central transmission

Question 41

what is caused by substance P being released from free nerve endings?

Answer 41

• vasodilation
• mast cell degranulation
• axon reflex

Question 42

Describe the sensitisation of nociceptors.

Answer 42

-Inflammatory “soup” +/- Axon reflex effects produce peripheral sensitisation
– Lowers the threshold

Allodynia = pain produced by a stimulus that
would NOT normally produce pain – e.g. Sunburn, tender tooth

Question 43

what blocks prostaglandin formation?

Answer 43

Cox inhibitors

Question 44

Describe non-steroidal anti-inflammatory drugs.

Answer 44

-Aspirin, Ibuprofen, Indomethacin

– non-selective COX inhibitor

Question 45

what does experience of pain depend on?

Answer 45

• usually, but not always, strength of stimulus or degree of tissue damage
• emotions
• past experience of pain
• ability to comprehend causes and consequences

Question 46

what does the sensory nervous system do?

Answer 46

-informs the CNS of the internal and external environment

Question 47

what is the role of the nociceptive system in the sensory nervous system?

Answer 47

signal the threat or occurrence of injury

Question 48

where are nociceptors especially found?

Answer 48

cornea and tooth pulp

Question 49

where are nociceptors lacking?

Answer 49

brain, liver,lung