Physiology of Pain

Question 1

why is pain difficult to asses

Answer 1

it is very subjective and tolerance varies between people

Question 2

what is pain

Answer 2

an unpleasant sensory and emotional experience associated with actual tissue damage or described in terms of such damage

Question 3

how does chronic pain prevalence change with age

Answer 3

more common in elderly

Question 4

what is transduction

Answer 4

translation of noxious stimulus into electrical activity at the peripheral nociceptor (how body conveys stimulus to CNS)

Question 5

what is transmission

Answer 5

propagation of pain signal as nerve impulses through the nervous system

Question 6

what is modulation

Answer 6

modification/hindering of pain transmission in the nervous system by inhibitory neurotransmitters like endogenous opioids

Question 7

what is perception

Answer 7

conscious experience of pain

Question 8

where does pain begin

Answer 8

with the activation of nociceptors

Question 9

what are nociceptors

Answer 9

specific primary sensory afferent neurons normally activated by intense noxious stimuli

Question 10

what are the neurotransmitters in the nociceptive pathway

Answer 10

glutamate and peptides

Question 11

are nociceptors first or second order neurons

Answer 11

first order

Question 12

through what system do the second order neurons ascent the spinal cord

Answer 12

the anterolateral system terminating in the thalamus

Question 13

what does the spinothalamic tract do

Answer 13

involved in pain perception

Question 14

what does the spinoreticular tract do

Answer 14

involved in autonomic responses to pain, arousal, emotional responses, fear of pain

Question 15

what relays the sensory information from the thalamus to the primary sensory contex

Answer 15

third order neurons

Question 16

what are A gamma fibres

Answer 16

mechanical/thermal nociceptors that are thinly myelinated

respond to mechanical and thermal stimuli , mediate ‘first’ or fast pain

Question 17

what are C fibres

Answer 17

nocioceptors that are unmyelinated and collectively respond to all noxious stimuli eg. polymodal and mediate ‘second’ or slow pain

Question 18

examples of pain felt through A gamma fibres

Answer 18

lancinating
stabbing
pricking

Question 19

pain sensations felt through C fibres

Answer 19

burning
throbbing
cramping
aching

Question 20

what is nociceptive pain

Answer 20

pain that is a normal response to injury of tissue by damaging stimuli

only provoked by intense stimulation of nocioceptors

adaptive (changed with healing)

Question 21

why do we have nociceptive pain

Answer 21

as an early warning physiological protective system to detect and avoid noxious stimuli

Question 22

what is inflammatory pain

Answer 22

caused by activation of the immune system by tissue injury or infection

activated by mediators released at the site of inflammation

also causes heightened pain sensitivity to noxious stimuli (hyperalgesia)

adaptive pain (changes with healing)

Question 23

why do you get heightens sensitivity to noxious pain when there is inflammation

Answer 23

to discourage physical contact with the affected part and movement

Question 24

what is neuropathic pain

Answer 24

pathological pain

caused by damage to neural tissue

Question 25

what are some examples of neuropathic pain

Answer 25

compression neuropathy 
peripheral neuropathy 
central pain (following stroke or spinal injury) 
post therautic neuralgia 
trigeminal neuralgia 
phantom limb

Question 26

how is neuropathic pain perceived

Answer 26

as burning 
shooting 
numbness 
pins and needles 
may be less localised

Question 27

what is dysfunctional pain

Answer 27

pathological pain
no identifiable damage or inflammation
simple analgesics not usually very effective
maladaptive pain (not protective)

Question 28

examples of dysfunctional pain

Answer 28

fibromyalgia 
IBS
tension headache 
temporomandibular joint disease 
intersititial cystitis

Question 29

What is referred pain

Answer 29

pain developed in one part of the body felt in another structure away from the place of its development

Question 30

what types of pain can be referred

Answer 30

deep or visceral pain

Question 31

what causes referred pain

Answer 31

convergence of nociceptive visceral and skin afferents upon the same spinothalamic neurons at the same spinal level

(brain gets confused)

Question 32

where can pain from the heart be referred to

Answer 32

the jaw

down the left arm

Question 33

where can pain from the liver be referred to

Answer 33

the right shoulder

Question 34

where can pain from the diaphragm and lungs be referred to

Answer 34

the left shoulder

Question 35

where can pain from the stomach/appendix be referred to

Answer 35

epigastric region

Question 36

where can pain from the gallbladder be referred to

Answer 36

right shoulder