Pain

Question 1

Pain

Pathway

Initiation/Propagated/Perception

Answer 1

• initiation = injury site pain receptor
• Propagation = spinal cord (spinothalamic) –> thalamus
• Perception = somatosensory, emotional, cognitive brain areas

Question 2

Pain fibers w/ ______ fibers

Answer 2

Temp

Question 3

Temp that sets off pain fibers

Answer 3

37 degrees C (tissue damage)

Question 4

Nociceptor - adaptation

Answer 4

Slow

Question 5

Pain pathway

Injured tissue

Answer 5

Releases glutamate to C fibers , next fiber releases substance P onto paleo, cascade, depole paleo neurons

Question 6

Differences b/w C + A pain fibers?

Answer 6

LOOK UP, NOT SURE
C
*unmyelinated
*second pain = dull/aching, chronic

A

• myelinated
• “first pain” = sharp/stingin, intense

Question 7

Painful stimulus derived from external stimulus

Answer 7

Nociceptive pain

Question 8

Pain receptors

Answer 8

trauma, burning, temp, cold = each has DIFF receptor

Question 9

Nociceptive pain affected by

Answer 9

• local anesthetics
• Cox 2 inhibitors
• opioids

Question 10

TRPV1 Receptor

Answer 10

• Nociception
• activated by Heat/Capsaicin/Acid

*Non-selective Ca2+ channels

Question 11

Pain from internal stimulus

Answer 11

Inflammatory Pain

Mediators activate: Histamine, serotonin, bradykinin, prostaglandins, protons
= bind to specific receptors on the nerve

Question 12

Inflammatory pain

Tx w/

Answer 12

Local anesthetics
Cox 2 blocker
Opiates

Question 13

Sensitizing pain fibers

Answer 13

Inflammatory + nociceptive

Question 14

Hyperalgesia

Answer 14

Inflammatory mediators activating pain fiber receptors phosphorylate (phosph A2), sensitize fibers, increased AP firing, up pain

Question 15

Allodynia

Answer 15

Inflammatory mediators sensitize receptors , non-painful even leads to pain

Question 16

Damaged elements of PNS/CNS

Answer 16

Neuropathic pain

Question 17

Neuropathic Pain

tx

Answer 17

NO NSAIDS

• Opioids (some respond, if no ……
• ->*Atypical analgesics: TCA, Anti-convulsants, CCBs

Question 18

Neuropathic pain

Causes

Answer 18

Metabolic
Injury
Infections
Neurotoxins

DAMAGE/REWIRE pain pathway
ABeta fibers (non-mechanical pain) = now activate w/ touch

Question 19

2 components of pain processing

Answer 19

• Discriminative = Where, how much

* affective - emotional

Question 20

Descending pain pathway

Answer 20

• endogenous + exogenous opioids = inhibit ascending pain pathway (A+C fibers and spinothalamic neurons)
• Local anesthetics = (C+A only)

Question 21

Pain with unexplained source?

Answer 21

Think referred pain!

*visceral + cutaneous afferents converge into same spinothalamic tract

Question 22

Rub bumped elbow and it hurts less?

Answer 22

Gate theory

*rub area activates ABeta fibers–>activate inhibitory local circuit n. –> supress paleospinothalamic n.

Question 23

Phantom pain

Answer 23

Amputation = movement neurons gone/degenerate

Spinothalamic n. Rewire to another mechanostimulus in intact body part, rubbing body part gives pain

Question 24

How do nociceptive AND inflammatory pain both lead to Hyperalgesia / Allodynia?

Answer 24

Both lead to release of inflammatory mediators (prostaglandins) at injury site

• nociceptive = recruited immune cells
• allodynia = local tissue release (immune cells at site) of inflammatory mediators