The Case of the Screaming Agony

Question 1

3 types of pain

Answer 1

nociceptive, inflammatory, neuropathic

Question 2

nociceptive pain

Answer 2

normal response to real or threatened non-neuronal tissue damage

Question 3

is nociceptive pain reversible or irreversible?

Answer 3

reversible

Question 4

how do nociceptors transmit pain to dorsal horn?

Answer 4

via ad or c fibres

Question 5

a-delta fibres

Answer 5

fast acting and transmit initial sharp pain, some myelin

Question 6

c fibres

Answer 6

transmit slower, dull pain, no myelin

Question 7

Where are nociceptors located? (5)

Answer 7

skin
joints
connective tissue
muscle
bone

Question 8

what does visceral pain feel like?

Answer 8

diffuse, aching, cramping, poorly localised

Question 9

autonomic symptoms associated with visceral pain

Answer 9

sweating, nausea, vomiting

Question 10

which fibres transmit visceral pain?

Answer 10

which fibres transmit visceral pain?

autonomic fibres so poorly localised

Question 11

2 types of nociceptive pain

Answer 11

somatic and visceral

Question 12

inflammatory pain

Answer 12

pain that signals some type of tissue damage and inflammation

Question 13

how does peripheral sensitisation happen?

Answer 13

inflammatory mediators e.g. cytokines, substance P sensitive local nociceptors and cause exaggerated responses

Question 14

what happens at sites of tissue damage?what gets released?

Answer 14

cytokines, prostaglandins, ATP, H+, bradykinin, NO released, all directly or indirectly activate or sensitise nociceptors

Question 15

neuropathic pain

Answer 15

pain from damage to neurons of either the peripheral or central nervous system

Question 16

symptoms of neuropathic pain

Answer 16

sharp, stabbing, tingling, burning, electric shock; onset of high intensity (Example: phantom pain)

Question 17

allodynia

Answer 17

Pain due to a stimulus that does not normally provoke pain

Question 18

Hyperalgesia

Answer 18

excessive sensitivity to painful stimuli

Question 19

hyperpathia

Answer 19

pain that continues after stimuli removed

Question 20

what sensory changes does nerve damage cause?

Answer 20

sensory loss

increased responsiveness to noxious and innocuous stimuli

Question 21

what pain mechanisms involved in vascular pain?

Answer 21

all 3: neuropathic, nociceptive and inflammatory mechanisms

Question 22

Define pain

Answer 22

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

Question 23

factors influencing pain

Answer 23

factors influencing pain

physiological, social, psychological, pain tolerance, personality, cultural

Question 24

which inflammatory mediators directly activate nociceptors?

Answer 24

ATP and H+

Question 25

what stimuli do a-delta fibres respond to?

Answer 25

mechanical or thermal stimuli

Question 26

what stimuli do c fibres respond to?

Answer 26

mechanical, thermal or chemical

Question 27

2 spinal pathways which carry pain

Answer 27

spinothalamic | spinoreticular

Question 28

path of neurons in spinothalamic pathway

Answer 28

1st order neurone enters dorsal horn, ascends 1/2 levels in tract of lissaeur, synapses with 2nd order neurone which crosses over, ascends to thalamus

Question 29

2 spinothalamic tracts

Answer 29

lateral neo-spinothalamic tract | medial paleo-spinaothalamic tract

Question 30

what is the dorsal horn divided into?

Answer 30

Rexed lamina

Question 31

where do c fibres terminate in dorsal horn?

Answer 31

substantia gelatinosa aka lamina 2

Question 32

where do a-delta fibres terminate in dorsal horn?

Answer 32

lamina 1 and 5

Question 33

The destination of the neospinothalamic tract is ___________.

Answer 33

ventral posterior lateral nucleus of thalamus

Question 34

what does Neo-spinothalamic tract carry?

Answer 34

sensory-discriminative aspect of pain

Question 35

destination of paleospinothalamic tract is?

Answer 35

medial thalamus, hypothalamus and periaqueductal gray

Question 36

where does spinoreticular tract end?

Answer 36

reticular formation in the medulla oblangata, pons, and midbrain

Question 37

Where do 3rd order neurons synapse?

Answer 37

primary somatosensory cortex, also may project to insula and anterior cingulate cortex

Question 38

Where is the insula and what does it do?

Answer 38

deep within the lateral sulcus, deals with visceral nociceptive input

Question 39

where is anterior cingulate cortex and what does it do?

Answer 39

around front of corpus callosum, does attention and memory of pain

Question 40

gate control theory of pain

Answer 40

theory that if a-beta fibres are activated by mechanical stimuli they activate inhibitory interneurons which stop c fibres transmitting pain (if you press an injury it may stop hurting)

Question 41

where do descending pain inhibitory pathways originate?

Answer 41

periaqueductal gray reticular formation nucleus raphe Magnus

Question 42

what receptors are expressed in PAG, reticular formation and nucleus raphe Magnus?

Answer 42

endogenous opioid receptors

Question 43

how do descending inhibitory pathways work?

Answer 43

serotonin and noradrenaline action inhibit substance P and glutamate release at level of dorsal horn

Question 44

what part of pain pathway do NSAIDs work on?

Answer 44

nociceptor terminals

Question 45

what part of pain pathway do antidepressants work on?

Answer 45

enhance activity of descending inhibition

Question 46

what parts of pain pathway do opioids work on?

Answer 46

brain, nociceptor terminals and dorsal horn

Question 47

what neurotransmitter do alpha delta fibres release?

Answer 47

glutamate

Question 48

what neurotransmitter do c fibres release?

Answer 48

substance P

Question 49

how does central sensitisation work ?

Answer 49

prolonged glutamate release causes more NMDA receptor insertion or hyper responsiveness

Question 50

where is the nucleus raphe Magnus located?

Answer 50

in rostroventrolmedial medulla

Question 51

how does endogenous opioid system reduce pain?

Answer 51

blocks 1st order neurones from releasing NT stops release of AP from 2nd order neurones less pain transmission