Physiology of Pain

Question 1

nociceptive pain

Answer 1

occurs immediately after tissue insult, one moves away from source of pain and prevents further damage

Question 2

what are nociceptor neurones

Answer 2

primary sensory afferent neurones

Question 3

what are nociceptor neuroens activated by

Answer 3

intense stimuli - high threshold

Question 4

describe the transmission of signal in nociceptor neurones

Answer 4

activated by extreme stimulation at peripheral terminal of neurones, depolarisation and initiation of AP. travels along axon to central terminal of neurone. neurotransmitters released

overrides most other ongoing activites of the nervous system to initiate a withdrawal reflex

Question 5

what type of pain is not adaptive

Answer 5

pathological

Question 6

what is the result of a nociceptor signal

Answer 6

initiate withdrawal reflex, unpleasant - adverse emotions, makes memories to avoid harm in future

Question 7

what are the 2 types of nociceptor

Answer 7

A and C fibres

Question 8

A nociceptor fibres

Answer 8

thinly myelinated so conduct fast, and mediate first, fast pain eg stabbing, pricking

Question 9

C nociceptor fibres

Answer 9

unmyelinated so conduct slower and mediate slow, second pain eg dull ache, burning, throbbing

Question 10

what are the 2 forms of pain hypersensitivity caused by inflammatory pain

Answer 10

increased responsiveness and allodynia

Question 11

define allodynia

Answer 11

triggering of pain response from stimuli that doesnt normally evoke pain

Question 12

what is inflammatory pain caused by

Answer 12

activation of immune system in injury or infection

Question 13

how does inflammatory pain assist in the healing of a damaged body part

Answer 13

pain hypersensivity discourages physical contact and movement until injury is healed

Question 14

pathological pain

Answer 14

maladaptive with no protective function disease state caused by damage to the nervous system or by its abnormal function

Question 15

what are the 2 forms of pathological pain

Answer 15

neuropathic (peripheral nerve damage) and dysfunctional (normal nerves but spontaenous pain)

Question 16

congenital insensitivity to pain

Answer 16

due to mutations in SCN9A gene that encodes Na channels in nociceptive neurones

Question 17

describe the relationship between stimulus strength and ampltiude of receptor potential

Answer 17

non - linear, greatest sensitivity to change at low stimulus strength

Question 18

what is the intensity of stimulus coded by

Answer 18

receptor potential and frequency of AP discharge