VII- Pain Phys

Question 1

brain areas of sensory pain

Answer 1

primary and secondary somatosensory cortices

Question 2

components of pain

Answer 2

1. sensory- discriminative perception of location, intensity, modality of stim
2. motivation- affective, emotional, neg impact mood

Question 3

acute pain

Answer 3

-critical for survival bc warning signal to protect from damage/injury
-felt within 0.1 sec after stim
-very adaptive so as tissue injury heals pain lessens

Question 4

acute pain conduction

Answer 4

FAST via A-delta fibers
-elicited by mechanical or thermal pain
-sharp, prickling, electric, cutting sensations

Question 5

chronic pain

Answer 5

usually associated with tissue injury- pathologic and maladaptive so even if no more tissue damage

Question 6

chronic pain conduction

Answer 6

persistent and slow conduction via C fibers
-elicited by chem, mechanical, thermal stim
-dull, throbbing, aching, nauseous sensation
-strong emotional part

Question 7

step 1 of pain processing

Answer 7

peripheral transduction of noxious signal

Question 8

step 2 of pain processing

Answer 8

transmission of noxious signal from periphery to spinal cord

Question 9

step 3 of pain processing

Answer 9

spinal modulation and amplification of noxious stimuli

Question 10

step 4 of pain processing

Answer 10

supraspinal perception

Question 11

nociceptor/inflamm soup

Answer 11

1. activation of nociceptors > opens Na channels for depolar and generating AP
2. vasodilation
3. inflammation

CGRP, Substance P, bradykinin, prostaglandins release

Question 12

peripheral hyperalgesia

Answer 12

inc response to stimulus that is normally painful

Question 13

peripheral sensitization

Answer 13

spreading action potentials over other areas where membrane is at resting state to
-inc sensitivity, receptive field size
-induce inflamm mediators and substance P
-activate silent nociceptors

Question 14

wind up phenomenon

Answer 14

recruitment of adjacent neurons + release of glutamate, sub P, BDNF

Question 15

central sensitization

Question 16

allodynia

Answer 16

pain from non-noxious stimuli
-like clothing causing pain when sunburnt

Question 17

gate control theory

Answer 17

gate will close in resp to normal stim of fast conductivity so large nerve fibers like A-beta (touch, proprio)

Question 18

descending pain control

Answer 18

1. spinoreticular tract to reticular formation for motor resp
2. spinomesencephalic tract from midbrain PAG for regulation/modulation of pain experience, involved with superior colliculus for eye movement

Question 19

common pain types

Answer 19

1. referred - via reflective pain or convergence
2. projected- pain in one area affects nerve supply to distant area along distribution
3. phantom
4. sympathetic mediate- complex regional pain syndrome, reflex sympathetic dystrophy causalgia

Question 20

brain area of affective pain

Answer 20

frontal cortex, limbic system, brainstem area

Question 21

inflammatory pain features

Answer 21

protective and promotes healing
-can be acute and chronic from tissue damage, inflamm process, hypersensitivity

Question 22

types of pain with no protective function

Answer 22

1. neuropathic - from damage to nervous system thats disproportionate to intensity of activation, pathologic and maladaptive
2. dysfunctional - no understanding lesion found, disproportionate to tissue injury like IBS

Question 23

somatic pain

Answer 23

1. superficial - initial and sharp by A delta or delayed and dull/burning by C fibers
2. deep - CT, bones, joints, headache

Question 24

visceral pain

Answer 24

primarily mediated by C fibers
-poorly localizing, nauseating, sweating
-radiates or refers

Question 25

dorsal horn lamina

Answer 25

I, II, V = A-delta for fast, acute pain
II, III, V = C fibers for slow, chronic
V = wide dynamic range neurons, noxious and non noxious signals

Question 26

neospinothalamic tract

Answer 26

ascending from lamina I, II, V of anterolateral column to VPL > primary sensory cortex
-so fast type A-delta fibers of sharp well localized pain
-sensory

Question 27

paleospinothalamic tract

Answer 27

from lamina II, III,V of anterolateral column to dorsomedial nucleus of thalamus > limbic
-slow type C fibers so dull, throbbing
-emotional

Question 28

sites of action by descending pain control

Answer 28

1. periaqueductal gray @ midbrain- activates enkephalin releasing neurons that project to raphe nuclei in brainstem
2. rostral ventral medulla @ brainstem - 5HT projections to dorsal horn of spinal cord
3. locus coeruleus @ pons - NE projections to spinal cord

Question 29

RSD symptoms

Answer 29

-continuous burning pain after trivial injuries
-can develop after trauma
-hyperplagia
-dystrophic changes to skin, hair, nails
-symp hyperactivity so temp changes and hyperhidrosis
-enhanced by allodynia and symp activation

treat with sympathetctomy