MSK - PAIN PHYSIOLOGY

Question 1

what is pain?

Answer 1

an unpleasant sensory and emotional experience assoc with actual tissue damage or described in terms of damage

Question 2

processes involved in pain

Answer 2

transduction
transmission
modulation
perception

Question 3

transduction

Answer 3

translation of noxious stimulus into electrical activity at the peripheral nociceptor

Question 4

transmission

Answer 4

propagation of pain signal as nerve impulses through the nervous system

Question 5

modulation

Answer 5

modification/hindering of pain transmission in the NS eg by inhibitory neurotransmitters like endogenous steroids

Question 6

perception

Answer 6

conscious experience of pain

causes physiological and behavioural responses

Question 7

what begins pain?

Answer 7

activation of nociceptors

Question 8

what are nociceptors?

Answer 8

specific primary afferent neurones normally activated by intense noxious stimuli eg thermal, mechanical or chemical

Question 9

how do nociceptors relay information to second order neurones?

Answer 9

chemical synaptic transmission

Question 10

what are the neurotransmitters?

Answer 10

glutamate and peptides eg substance P and neurokinin A

Question 11

how do second order neurones ascend the spinal cord?

Answer 11

the anterolateral system terminating in the thalamus

Question 12

which tracts are involved?

Answer 12

spinothalamic tract

spinoreticular tract

Question 13

what happens in the spinothalamic tract?

Answer 13

pain perception - location and intensity

Question 14

what happens in the spinoreticular tract?

Answer 14

autonomic responses to pain, arousal, emotional responses, fear of pain

Question 15

where does the sensory information go after the thalamus?

Answer 15

it is relayed by third order neurones to the primary sensory cortex

Question 16

what are the types of nociceptors?

Answer 16

Adelta fibres

C fibres

Question 17

both types of nociceptors are myelinated. true/false

Answer 17

false

only adelta fibres are (thinly myelinated)

Question 18

what do adelta fibres mediate?

Answer 18

first or fast pain eg lancinating, stabbing, pricking sensations

Question 19

what do c fibres mediate?

Answer 19

second or slow pain eg burning, throbbing, aching sensations

Question 20

what are the classifications of mechanisms of pain?

Answer 20

nociceptive
inflammatory
pathological

Question 21

what is nociceptive pain and when is it provoked?

Answer 21

normal response to injury of tissues by damaging stimuli

only provoked by intense stimulation

Question 22

what is special about nociceptive and inflammatory pain?

Answer 22

adaptive
n- healing -> pain goes away)
I - promotes repair until healing occurs

Question 23

what causes inflammatory pain?

Answer 23

activation of the immune system by tissue injury or infection

Question 24

what activates the pain in inflammatory?

Answer 24

mediators released at the site of inflammation by leucocytes, vascular endothelium and tissue resident mast cells

Question 25

what is hyperalgesia (caused by inflammatory pain)?

Answer 25

heightened pain sensitivity to noxious stimuli

Question 26

what is allodynia (caused by inflammatory pain)?

Answer 26

pain sensitivity to innocuous stimuli

Question 27

when is pain pathological?

Answer 27

when simple analgesics are no longer effective

Question 28

what is pathological pain treated with?

Answer 28

antidepressants and anti epileptics

Question 29

what are the two types of pathological pain?

Answer 29

dysfunctional and neuropathic

Question 30

what is dysfunctional pain?

Answer 30

when there is no identifiable damage or inflammation

Question 31

what is neuropathic pain?

Answer 31

caused by damage to neural tissue

Question 32

how is neuropathic pain usually perceived?

Answer 32

burning, shooting, numbness, pins and needles | less localised

Question 33

what are the 3 time courses of pain?

Answer 33

acute chronic breakthrough (all of a sudden on top of chronic pain eg cancer)

Question 34

how to describe the severity of pain?

Answer 34

mild moderate severe

Question 35

what are the 2 sources of origin of pain?

Answer 35

somatic | visceral

Question 36

what is referred pain?

Answer 36

deep or visceral pain developed in one part of the body felt in another structure away from its place of development

Question 37

what causes referred pain?

Answer 37

convergence of nociceptive visceral and skin afferents upon the same spinothalamic neurones at the same spinal level