Pain

Question 1

2 types of pain

Answer 1

nociceptive: normal pain responding
neuropathic: malfunctioning pain reporting system

Question 2

2 types of nociceptive mechs.

Answer 2

1. tissue damage

2. inflammatory pain

Question 3

4 types of neuropathic pain

Answer 3

1. post-herpetic
2. central pain
3. phantom limb
4. diabetic neuropathy

Question 4

3 types of nociceptors, what they respond to and fibers

Answer 4

1. thermal, 5-45C, Adelta
2. mechanical - intense pressure, Adelta
3. polymodal - mechanical, chemical, thermal - C

Question 5

2 phases of pain signal

Answer 5

1. well localized fast pain

2. slow, diffuse distressing pain

Question 6

2 immediate reactions to pain

Answer 6

1. withdrawal relfex - flexor muscles

2. perception of pain

Question 7

2 mechanisms of inflammation

Answer 7

1. neurogenic - axon reflex

2. tissues damage

Question 8

3 chars of inflammation

Answer 8

1. redness -rubor
2. warmth - calor
3. swelling - tumor

Question 9

where is origin of axon relfex

Answer 9

C fiber at site of lesion

Question 10

what is released in axon reflex

Answer 10

CGRP and substance P

Question 11

3 targets of axon reflex

Answer 11

1. blood vessels (permeability, vasodilation, bradykinin)
2. mast cells (histamine release)
3. platelets - 5HT release

Question 12

3 pathways that activate nociceptors

Answer 12

1. mast cells>histamine
2. platelets>5HT
3. plasma>bradykinin

Question 13

4 pathways that sensitize nociceptors

Answer 13

From damaged cells
1. K
2. prostaglandins
3. leukotreins
From axons
4. substance P

Question 14

2 types of hyperalgesia

Answer 14

1. primary - in region skin is damaged

2. secondary - in adjacent undamaged skin

Question 15

how do NSAIDs work

Answer 15

COX inhib. so don’t get prostaglandins, which would senstize the nociceptors

Question 16

2 ways nociception is integrates in dorsal horn

Answer 16

1. convergent afferents from visc. and body

2. inhib. from touch afferents

Question 17

what are fibers that open and close pain gate

Answer 17

open - direct Adelta and C fibers

close - Abeta activate inhibitory interneuron to close the gate

Question 18

where do descending input to the dorsal horn orig.

Answer 18

periaqueductal grey of the brainstem

Question 19

what does desceding input lead to

Answer 19

release of enkephalins (endogenous opids)

Question 20

2 ways opiods work

Answer 20

1. inhbit NT release from promary afferent nerve

2. hyperpolarize the secondary neuron

Question 21

how does emotion get brought into pain

Answer 21

3rd neurons from the VP thalmus also project to limbic system