oral sensation pain

Question 1

Source of pain (6)

Answer 1

Visceral
Thalamic
Neuropathic
Psychosomatic
Referred
Phantom

Question 2

Factor affecting pain

Answer 2

Intensity of stimulation or dmg
Emotions
Past experience
Gender, ethnicity age
placebo

Question 3

what mediators activates nociceptor in pain?

Answer 3

Potassium-Damaged cells
Bradykinin- Damaged vessels
Serotonin- damaged endothelial cells and Platelets
Histamine- Mast cells

Question 4

what are mediators sensitize nociceptor in pain?

Answer 4

substance P
prostaglandin

Question 5

Explain antidromic activation of nociceptors (axon reflex)

Answer 5

The axon-reflex can be induced by stimulation of small nerve fiber terminals in the skin.
An action potential is generated which is then conducted to an
upstream axon branching point
where the potential switches to neighboring small fibers to travel backward.
potential reaches distal areas near area of stimulation

Question 6

explain hot pulps

Answer 6

After antidromic activation of nociceptors,
one site of nociceptor being activated will stimulate other sites as well. this cause release in substance P and PG - sensitisation occur
bradykinin, potassium, serotonin and histamine released which activates nociceptors

increase in pain sensitivity. eventually, peripheral sensitisation occurs

Question 7

explain central sensitisation

Answer 7

after tissue injury/inflammation + peripheral nerve injury,

c fibre receives input from it.
summation of the slow synaptic potential

alteration of secondary messengers - protein kinase activated

increased excitability + synaptic efficiency

Question 8

central sensitisation can lead to

Answer 8

allydonia and hyperalgesia

Question 9

explain trigeminal pathway

Answer 9

ii. 1st order neurons from Trigeminal ganglion – carry nociceptive information from orofacial region into brainstem (pons first)
iii. Goes to pons, then descend down to spinal nucleus (this pathway is called spinothalamic tract
iv. Axon from 2nd order neuron cross midline then ascend up to contralateral thalamus (trigemino-thalamic tract) and go up to the VPM nucleus or medial thalamic nuclei through the limnic system
(3rd order neuron, from thalamus to cortex)

Question 10

gate control theory

Answer 10

pain controlled by a mechanism whereby these fibres, S fibres facilitate transmission of sensory info while L fibre inhibit the transmission.

Question 11

referred pain

Answer 11

pain from viscera is felt in more superficial regions.

nociceptor fibre from viscera converge on same pain pathway as cutaneous fibres.

Question 12

theories of dentinal hypersensitivity

Answer 12

hydrodynamic theory
odontoblast transducer theory
neural theory

Question 13

in LA, what order fibre is anaesthesized?

Answer 13

C fibres - due to small size
small A delta - myelinated
large A delta fibres

Question 14

Susceptibility of nerve fibre to LA depends on?

Answer 14

Size of nerve fibre
State of myelination
Rate of firing