pain

Question 1

what is the definition of pain?

Answer 1

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

Question 2

what is the most common type of pain?

Answer 2

acute nociceptive pain

Question 3

when do we feel acute nociceptive pain?

Answer 3

when intense/noxious stimuli threaten to damage normal tissue- induced sensory reception

Question 4

why do we have acute pain?

Answer 4

protective function

Question 5

what is the perception of pain characterised by?

Answer 5

• high threshold
• limited duration

Question 6

what are the afferent axons which mediate pain?

Answer 6

• alpha delta fibres
• c fibres

Question 7

what type of pain corresponds to the a delta fibres?

Answer 7

sharp stabbing pain (first)

Question 8

what type of pain corresponds to the c fibre activity?

Answer 8

dull aching pain (second pain)

Question 9

what are the main features of nociceptor endings?

Answer 9

• free nerve endings
• high threshold of activation
• respond to intense (noxious) stimuli usually associated with pain
• carry several types of receptor proteins, each responsive to different noxious stimuli
• display sensitisation (more we use, easier to recruit)

Question 10

which fibres respond to noxious mechanical/heat stimuli?

Answer 10

a delta

Question 11

which type of fibres respond to polymodal stimuli?

Answer 11

c fibres

Question 12

describe the neuron path of the spinothalamic pathway?

Answer 12

• a delta/c fibres from pain source in periphery to dorsal horn
• 2nd neuron- axon crosses to other side of spinal cord to antero-lateral funiculus and up to the thalamus (through medulla, pons, midbrain, spinal lemniscus)
• 3rd neuron- from thalamus to cerebral cortex

Question 12

describe the neuron path of the spinothalamic pathway?

Answer 12

• a delta/c fibres from pain source in periphery to dorsal horn
• 2nd neuron- axon crosses to other side of spinal cord to antero-lateral funiculus and up to the thalamus (through medulla, pons, midbrain, spinal lemniscus)
• 3rd neuron- from thalamus to cerebral cortex

Question 13

what is the spinothalamic tract?

Answer 13

projection up the spine through the antero-lateral funiculus

Question 14

what questions should be asked when diagnosing pain?

Answer 14

• location
• pain quality (sharp/dull)
• pain intensity
• frequency/duration
• provoking/relieving events

Question 15

what are refferred pains?

Answer 15

• perceived in one part of the body, but the pathology is elsewhere
• pain usually refers from an internal organ to a superficial area eg skin
• referral due to a convergence of inputs in the CNS
• pains tend to be referred to sites of common embryological origin

Question 16

what are factor categories which can influence our perception of pain?

Answer 16

• genetic
• psychological
• situational
• emotional

Question 17

what does rubbing the affected area of pain activate?

Answer 17

a beta fibres which can activate a population of inhibitory intraneurons which inhibit the 2nd order neurons to block the perception of pain

Question 18

what is the function of the supraspinal loop?

Answer 18

dampening down activity in dorsal horn to reduce pain

Question 19

what are the 5 signs of inflammation?

Answer 19

• heat
• redness
• swelling
• pain
• loss of function

Question 20

white reaction

Question 21

how can pain be modulated?

Answer 21

local analgesics in the nerve endings of the 1st neuron