Endogenous Control of Pain

Question 1

adequate stimulus for pain

Answer 1

anything causing tissue damage

Question 2

peripheral receptors for pain

Answer 2

on free nerve endings

-branch out and disperse

Question 3

types of free nerve endings for pain

Answer 3

nociceptors
A-delta and C fibers
silent
thermoreceptors
mechanoreceptors

Question 4

A delta

Answer 4

small - light myelination

Question 5

C fibers

Answer 5

small - no myelination

Question 6

silent receptors

Answer 6

only with repeated pain stimuli

-or inflammation

Question 7

pain stimulates

Answer 7

attention
emotion
ANS
memory

Question 8

pain

Answer 8

perception of noxious stimulus

Question 9

nociceptive information

Answer 9

has multiple destinations

divergence

Question 10

spinothalamic tract

Answer 10

only conscious tract for pain

Question 11

brainstem

Answer 11

spinoreticular and spinomesencephalic tract

Question 12

hypothalamus

Answer 12

spinohypothalamic tract

Question 13

limbic system

Answer 13

indirectly via RF and hypothalamus

Question 14

spinothalamic tract

Answer 14

good localization
-because its contralateral and has somatotopy

easier to test as clinician
-because you are consciously aware

Question 15

spinoreticular and spinomesencephalic tracts

Answer 15

bad localization
-because bilateral pathways

good for attention, emotion, ANS, and memory

Question 16

noxious stimuli

Answer 16

not emotionally neutral events

Question 17

perception of pain

Answer 17

not an unchangeable property

-can modulate

Question 18

modulation of nociception

Answer 18

changes in nociceptors

• change in dorsal horn
• alter descending pathways

Question 19

hyperalgesia

Answer 19

increased pain response to noxious stimulus

-pain much more intense after secondary injury

Question 20

allodynia

Answer 20

pain perception to normally not painful stimulus

-ex/ sunburn

Question 21

tissue injury

Answer 21

release of inflammatory mediators

• decrease threshold of regular nociceptors
• recruit silent nociceptors

Question 22

axon reflex

Answer 22

pain stimuli come in

• free nerve endings have trigger zone
• great enough intensity, APs back out to free nerve endings
• for further vasodilation and inflammation

Question 23

modulation by descending pathways

Answer 23

input from hypothalamus, amygdala, cortex

• to periaqueductal gray (midbrain)
• synapse at nucleus raphe-magnus (caudal pons)
• to dorsal horn

Question 24

C fibers

Answer 24

absence of input from C fibers - tonic inhibition
-from interneurons
with strong pain - C fibers stop inhibition pathway
-allow stronger signal to go to brain

Question 25

reticular formation

Answer 25

level of alertness to pain

Question 26

hypothalamus

Answer 26

autonomic response to pain

Question 27

limbic system

Answer 27

emotional response to pain

Question 28

cognitive evaluation aspect

Answer 28

provides context, culture and experience

-mediated by association areas