Pain and Nociception

Question 1

nociception

Answer 1

neural process associated with pain

Question 2

nociceptive pain

Answer 2

normal pain mediated by A - delta and C fibres
elicited when intense stimuli threatens normal tissue (protective)
characterised by high threshold and limited duration

Question 3

what are the two types of clinical pain

Answer 3

acute

chronic

Question 4

acute clinical pain

Answer 4

results from soft tissue injury / inflammation

e.g infection in finger throbs

Question 5

chronic clinical pain

Answer 5

> 3 months of persistent pain
no survival advantage
resistant to treatment
result of ongoing nerve damage or pathology

Question 6

what fibres transmit a sharp stabbing pain

Answer 6

A-delta fibres

Question 7

what fibres transmit a dull throbbing pain

Answer 7

C fibres

Question 8

referred pain

Answer 8

felt in one part of the body but the pathology is elsewhere

often due to pain and pathology sites being from the same embryological origin

Question 9

what factors affect pain perception

Answer 9

genetics 
social 
psychological 
physiological 
anatomical

Question 10

in the spinothalamic pathway how does the 2nd neutron travel up the spinal cord

Answer 10

via the anterograde lateral funiculus

Question 11

gate control theory of pain

Answer 11

DCML which carries deep touch signals can inhibit pain signals carried by A-delta and C fibres via the spinothalamic tract

Question 12

how does the gate control theory of pain work

Answer 12

Painful signals are transmitted to 2nd neutron from 1st via excitatory neurotransmitters
when the DCML pathway is activated, it also activates inhibitory neutrons which release inhibitory neurotransmitters which reduces release of excitatory neurotransmitters from A-dleta and C fibres

Question 13

descending pain modulation brief

Answer 13

shows that stimulation of periaqueductal grey matter in the midbrain can result in production of endogenous opioids which have morphine like effects

Question 14

what are the three characteristics of the triple response

Answer 14

red reaction
wheal
flare

Question 15

what causes the red reaction in the triple response

Answer 15

vasodilation of capillaries due to effects of histamine

Question 16

what causes the wheal in the triple response

Answer 16

local swelling, due to cytokines increasing vascular permeability

Question 17

what causes the flare in the triple response

Answer 17

dilation of blood vessels

Question 18

why do general anaesthetics pose more risks than local anaesthetics

Answer 18

general anaesthetics must enter the CNS to have their effects
local anaesthetics have their effects at the receptor endings of the 1st order neutron in the periphery