Physiology: Pain and Thermosensation

Question 1

define pain

Answer 1

unpleasant sensory and emotional experience associated with tissue damage

Question 2

classification of pain

Answer 2

1. nociceptive
2. inflammatory
3. pathological

Question 3

what are nociceptors?

Answer 3

primary sensory afferents

Question 4

sub-types of nociceptors

Answer 4

1. A-delta fibres

2. C-fibres

Question 5

role of A-delta fibres

Answer 5

mediate fast pain, thinly myelinated

Question 6

role of C-fibres

Answer 6

mediate slow pain, unmyelinated

Question 7

what does noxious stimulation in the long-term cause?

Answer 7

increases spinal excitability contributing to hyperalgesia and allodynia

Question 8

what does neurogenic inflammation cause?

Answer 8

vasodilation
release of histamine
inflammatory soup

Question 9

what detects visceral pain?

Answer 9

nociceptors covering tissues and walls of organs

Question 10

characteristics of visceral pain

Answer 10

poorly localised

dull

Question 11

what causes referred pain?

Answer 11

visceral and skin afferents converge on the same spinothalamic neurones

Question 12

what do thermoreceptors detect?

Answer 12

small changes in temperature

Question 13

what is the gate control theory?

Answer 13

nociceptive information transmission is dependent on A-beta and C/A-delta fibre acitvity

Question 14

higher A-beta fibre activity

Answer 14

gate is closed so information from C/A-delta never gets to the brain

Question 15

higher C/A-delta activity

Answer 15

spinal gate is opened and pain is perceived in the substantia gelatinosa