Lecture 7 - Pain (2/4)

Question 1

Things like touch, vibration, coolness or warmth are sensed by ____ threshold receptors

Answer 1

low threshold receptors

Question 2

high threshold receptors sense stimuli such as

Answer 2

noxious heat or cold, pinch, crush, laceration, chemicals)

Question 3

what are the 2 main types of high-threshold afferents we discuss

Answer 3

1. A-delta fibres
2. C-polymodal (CPM)

Question 4

Which highthreshold fibres are myelinated and involved in sensing quick-sharp and localized pain?

Answer 4

A-delta fibres

Question 5

C polymodal (CPM) fibres are responsible for what type of pain due to the fact that they are unmyelinated?

Answer 5

dull ache, onsets slower after initial injury

Question 6

what is this image demonstrating?

Answer 6

that free nerve endings express a number of receptor terminals that respond to many things including noxious temp., chemical irritation or pressure. Also, the receptors present on each nerve ending vary.

Question 7

what about an action potential changes in the presence of noxious stimuli resulting in the body becoming more sensitive? (2)

Answer 7

1. the resting membrane potential might increase and activation threshold may decrease
2. the duration of the refractory period may decrease

Question 8

what changes about an action potential increase the sensitization of a cell?
a. amplitude
b. frequency

Answer 8

b. frequency

Question 9

Label parts A,B,C and D

Answer 9

a. myelinated axon
b. Schwann cell
c. fascicle
d. peripheral nerve

Question 9

what are the two secondary neurons we discussed?

Answer 9

1. Nociceptive specific
2. Wide Dynamic range (WDR)

Question 9

label the missing parts

Answer 9

A. lateral spinothalamic tract
B. Dorsal root ganglion

Question 10

what 3 factors affect the input of a A-delta or CPM nerve to a second-order neuron? (3)

Answer 10

1. descending input from CNS
2. A-beta fibres that synapse onto an interneuron (substantia gelatanosa) to create an inhibitory response as found in gate control theory.
3. electrical impulses through electrode stimulation

Question 11

what is the proposed role of glial cells in pain?

Answer 11

believe they have receptors for substance P and release NT of their own which might be picked up by WDR and stimulate the pain response. Because there are so many - can lead to chronic pain or pain moving to different areas outside of the injury site.

Question 12

Allodynia

Answer 12

pain due to a stimulus that does not normally provoke pain

Question 13

what causes allodynia?

Answer 13

convergence of signals from nociceptors and mechanoreceptors onto the lamina of the dorsal horn. when substance p is released due to pain sensation it can make other receptors more sensitive resulting in the feeling of pain with touch, etc.

Question 14

why is the neuromatrix model important in terms of treatment as physiotherapists?

Answer 14

demonstrates their are a number of different areas for and modes of treatment that may work to relieve patients symptoms

Question 15

what is this picture demonstrating in terms of chronic pain?

Answer 15

with chronic pain there is a shift In the neuroplasticity of the brain leading to pain sensation felt in many areas of the brain and rewiring’s taking control.

Question 16

can the brain of an individual with chronic pain be reversed back to a healthy brain threw rehabilitation? what example did we discuss in class?

Answer 16

yes effects of chronic pain in the brain can be reversed.
look at a study of 2pt discrimination of the index finger in people with and without complex regional pain syndrome

Question 17

what are the 5 pain mechanism classifications?

Answer 17

1. nociceptive (physiologic)
2. neuropathic (non-physiological)
3. central (nociplastic)
4. emotional
5. Visceral

Question 18

pain that is primarily driven by tissue stimuli that is intense enough to cause potential or actual damage is…

Answer 18

nociceptive

Question 19

which pain mechanism is orthodromic only?
A. Nociceptive
B. Neuropathic

Answer 19

A. Nociceptive
neuropathic also has action potentials that travel antidromically

Question 20

what are 3 types of stimuli sensed by nociceptive receptors?

Answer 20

1) mechanical (cut, crush)
2) thermal (burning, freezing)
3) chemical (inflammatory)

Question 21

clinical indicators such as:
predictable, consistent, associated with movement or pressure, tissue-based abnormality, and responds to NSAIDS are common to which type of pain mechanism?

Answer 21

nociceptive

Question 22

some clinical indicators of neuropathic pain include:

Answer 22

must be related to nerve pathology, can have unpredictable and inconsistent association with movement, localized to nerve distribution, strange symptoms, not responsive to NSAIDS

Question 23

some clinical indicators of nociplastic pain include:

Answer 23

usually more chronic, poor association with movement, no clear association with tissue abnormality, might be amendable to opioids but not NSAIDS

Question 24

the clinical indicators such as difficult to locate at time, pain usually related to negative emotions, no clear association with movement or tissue abnormalities, no response to NSAIDS is said to be which pain mechanism?

Answer 24

emotional

Question 25

what are some clinical indicators of visceral pain

Answer 25

poorly localized, not normally related to movement but may be worse in certain postures depending on the organ, often occurs with other symptoms, no response to NSAIDS or mechanical therapies

Question 26

pain that is primarily driven by action potentials arising from a damaged nerve is

Answer 26

neuropathic (non-physiological)

Question 27

pain that is primarily driven by abnormal CNS activity is:

Answer 27

central (nociplastic)

Question 28

pain that is primarily driven by strong negative emotions is:

Answer 28

emotional

Question 29

pain that is primarily driven by stimuli arising from the viscera more likely due to inflammation, chemical irritation or ischemia is:

Answer 29

visceral

Question 30

what is his preferred definition of pain duration?

Answer 30

it’s not the duration of pain that differentiates acute from chronic but rather the inability of the body to restore homeostasis.

Question 31

time frame of acute pain

Answer 31

3-6 weeks

Question 32

time frame of subacute pain

Answer 32

3-6weeks to 3-6months post injury

Question 33

time frame of chronic pain

Answer 33

pain lasting 3-6months after onset

Question 34

what type of pain duration is seen as adaptive or protective?

Answer 34

acute

Question 35

what type of pain duration is seen as non-adaptive or non-protective

Answer 35

chronic