physiology and pathophysiology of pain

Question 1

what part of the brain does pain get transmitted to?

Answer 1

thalamus

Question 2

what is nociception?

Answer 2

the detection of tissue damage by specialized transducers connected to A-delta and C fibres

Question 3

what are nociceptors?

Answer 3

free nerve ending of A delta and C fibres

Question 4

what do nociceptors respond to?

Answer 4

thermal,chemical, mechanical noxious stimuli

Question 5

where do nociceptors synapse?

Answer 5

spinal cord

Question 6

what type of pain are A delta fibres responsible for?

Answer 6

sharp or “first” pain

Question 7

what type of pain are C fibres responsible for?

Answer 7

dull pain which comes after the initial sharp pain

Question 8

what are the 3 types of neurons that are predominantly found in grey matter?

Answer 8

low threshold mechanoreceptive neurons
nociceptive specific neurons
wide dynamic range neurons

Question 9

where do the spinothalamic tracts relay information to in the brain?

Answer 9

thalamus

Question 10

what rexed areas does the spinothalamic tract arise from?

Answer 10

2 and 5

Question 11

where does the LATERAL STT terminate?

Answer 11

ventroposterior thalamic nuclei

Question 12

where do the ventroposterior thalamic nuclei feed to?

Answer 12

somatosensory cortex

Question 13

where does the VENTRAL STT terminate?

Answer 13

medial thalamic nuclei

Question 14

where do the medial thalamic nuclei project to?

Answer 14

limbic system
anterior cingulate cortex
insular cortex

Question 15

where does pain perception occur?

Answer 15

somatosensory cortex

Question 16

what is the lateral part of the pain matrix composed of?

Answer 16

somatosensory cortex

ventroposterior thalamic nuclei

Question 17

what is the medial part of the pain matrix composed of?

Answer 17

amygdala
hippocampus
cingulate and prefrontal cortexes
insula
brainstem centres

Question 18

what is the lateral part of the pain matrix involved in?

Answer 18

sensory discriminative part of nociception

Question 19

what is the medial part of the pain matrix involved in?

Answer 19

affective and emotional components as well as descending control of pain

Question 20

where are descending pathways located?

Answer 20

from the brain to the dorsal horn

Question 21

what is the usual effect of descending pathways?

Answer 21

usually decrease pain signal

Question 22

what kind of system are descending pathways?

Answer 22

noradrenergic system

Question 23

what is hyperalgesia?

Answer 23

leftward shift of the stimulus response curve; increased perception of pain or perception of non noxious stimuli as noxious

Question 24

when does hyperalgesia occur?

Answer 24

whenever there is tissue damage and inflammation?

Question 25

what is primary hyperalgesia?

Answer 25

hyperalgesia at the site of injury

Question 26

what is secondary hyperalgesia?

Answer 26

hyperalgesia in tissue surrounding the injury

Question 27

what is allodynia?

Answer 27

dynamic mechanical hyperalgesia brought on by light touch

Question 28

what changes occur in nociceptors in hyperalgesia?

Answer 28

exaggerated response to normal and supranormal stimuli

Question 29

what is central sensitization?

Answer 29

response of second order neurons in the CNS to normal input which can be both noxious or non noxious

Question 30

what are the 3 components of central sensitization?

Answer 30

wind up classical long term potentiation

Question 31

what kind of synapses does the wind up phase of central sensitization involve?

Answer 31

only activated synapses

Question 32

what effect does the wind up phase have on the neurons it affects?

Answer 32

progressively increases the response of the neurons

Question 33

when does the wind up phase manifest?

Answer 33

only over the course of a stimulus and ends with the stimulus

Question 34

what does the classic phase of central sens. involve?

Answer 34

opening of new synapses - new synapses start to receive input and record nociception

Question 35

what is the wind up mechanism chemically mediated by?

Answer 35

substance P and CGRP

Question 36

what receptor when activated by glutamate can trigger classical central sensitization?

Answer 36

NMDA

Question 37

what is the clinical reuslt of classical central sensitization?

Answer 37

secondary hyperalgesia

Question 38

how can classical central sens. be maintained after it has been activated?

Answer 38

low intensity of the offending stimuli

Question 39

what are 2 types of central sensitization?

Answer 39

segmental | suprasegmental

Question 40

what is nociceptive pain?

Answer 40

pain that occurs when specific peripheral sensory neurones respond to noxious stimuli

Question 41

what are some features of nociceptive pain?

Answer 41

pain typically localised at site of injury usually time limited and resolves when damaged tissue heals tends to respond to conventional analgesics

Question 42

what is neuropathic pain?

Answer 42

pain initiated or caused by a primary lesion or dysfunction in the somato sensory nervous system

Question 43

what are some features of neuropathic pain?

Answer 43

painful region occurs in the neurological territory of the affected structure of the brain almost always chronic responds poorly to conventional anaesthetics

Question 44

what are some methods to stop pain transduction?

Answer 44

NSAIDs Ice rest

Question 45

what are some methods to stop pain transmission

Answer 45

opioids anticonvulsants DREZ cordotomy

Question 46

what are some ways to stop pain perception?

Answer 46

distraction relaxation mirror box therapy cognitive behavioural therapy

Question 47

does chronic pain serve a protective function?

Answer 47

no

Question 48

what are some ways to stop descending modulation of pain?

Answer 48

opioids antidepressants spinal cord stimulation