Pain

Question 1

3 types of pain?

Answer 1

physiological nociception, pathophysiological nociception, neuropathic nociception

Question 2

cause of physiological nociception?

Answer 2

tissue-damaging stimuli

Question 3

cause of pathophysiological nociception?

Answer 3

underlying disease

Question 4

cause of neuropathic nociception?

Answer 4

damage of nerves (abnormal since not relevant for hazard perception)

Question 5

2 location classification of pain?

Answer 5

somatic, visceral

Question 6

where do you feel somatic pain?

Answer 6

“outside” skin, mucles

Question 7

where do you feel visceral pain?

Answer 7

inside organs

Question 8

2 types of pain classification depending on duration?

Answer 8

chronic, acute

Question 9

what is direct nociceptor activation?

Answer 9

transient receptor potential channels (TRP) directly activating nociceptor

Question 10

what is indirect nociceptor activation?

Answer 10

intermediate molecules (eg. ATP) that activate channels that then activate nociceptor

Question 11

function of thermoreceptors?

Answer 11

sense cold/warmth

Question 12

2 types of nerve fibers?

Answer 12

C fibers, Adelta

Question 13

describe C fibers

Answer 13

small, unmyelinated = slower speed signal

Question 14

describe Adelta fibers

Answer 14

small, myelinated = faster speed signal

Question 15

describe how pain gets perceived

Answer 15

signal travels through

1. spinal cord
2. thalamus: senses and identifies type of pain
3. somatosensory cortex: perceives pain
4. medial thalamus sends signal to limbic structures -> emotional/aversive response to pain
5. amygdala: forms memory of the pain (involve emotional reaction)

Question 16

factors determining intensity of pain?

Answer 16

frequency of action potentials in nociceptors & fibers

Question 17

function of endogenous analgesic system?

Answer 17

reduces pain perception to allow for survival

Question 18

what’s central sensitization?

Answer 18

signal translation in CNS increases nociceptor responsiveness & sensitivity to pain

Question 19

what are opioid peptides?

Answer 19

small molecules that act like neurotransmitters to reduce pain perception (eg. eukephalin)

Question 20

How does eukephalin work to reduce pain perception?

Answer 20

spinal interneurons release eukephalin at the synapse of receptor neurons in the dorsal horn, inhibiting substance P release -> less pain impulses received by brain

Question 21

How do opioids work to mimick enkephalin?

Answer 21

dec. calcium influx into nociceptor -> dec. duration of action potential in nociceptor (due to less Ca ion channels letting Ca in) -> hyperpolarizes neurons of dorsal horn -> dec. pain perception

Question 22

hyperalgesia

Answer 22

painful stimulus triggers inc. pain response

Question 23

allodynia

Answer 23

pain after something normally not painful

Question 24

paresthesia

Answer 24

distorted sensation w/ no apparent physical cause

Question 25

dysesthesia

Answer 25

abnormal sensation, related to CNS