Physiology: Introduction to the Physiology of Pain

Question 1

Define transduction with relevance to pain

Answer 1

Translation of noxious stimulus into electrical activity at the peripheral nociceptor

Question 2

Define dysfunctional pain

Answer 2

Pathological pain with no identifiable damage or inflammation e.g. fibromyalgia

Question 3

Define neuropathic pain

Answer 3

Pathological pain caused by damage to neural tissue e.g. compression neuropathies

Question 4

Define referred pain

Answer 4

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

Question 5

Define inflammatory pain

Answer 5

Pain caused by activation of the immune system by tissue injury or infection which reduces physical contact and movement to promote repair

Question 6

Define nociceptive pain

Answer 6

Represents normal response to injury of tissues by noxious stimuli

Question 7

What are nociceptors?

Answer 7

Specific primary sensory (first-order) neurones innervating peripheral tissues, normally activated by intense noxious stimuli (e.g. mechanical, thermal or chemical)

Question 8

What is the spin-reticular tract?

Answer 8

Ascending pathway of the spinal cord involved in autonomic responses to pain, arousal, emotional responses, fear of pain

Question 9

What are second-order neurones?

Answer 9

Carry signals from the spinal cord to the thalamus

Question 10

What are C-fibres?

Answer 10

Nociceptors that are unmyelinated, collectively respond to all noxious stimuli (polymodal); mediate ‘second’ or slow pain

Question 11

What are first-order neurones?

Answer 11

Carry signals from the periphery to the spinal cord

Question 12

What causes referred pain?

Answer 12

Convergence of nociceptive visceral and skin afferents upon the same spinothalamic level, leading to pain in an area of the skin which is distant from the internal organ where the pain originates

Question 13

Define modulation with relevance to pain

Answer 13

Modification/hindering of pain transmission in the nervous system e.g. by inhibitory neurotransmitters like endogenous opioids

Question 14

What are third-order neurones?

Answer 14

Carry signals from the thalamus to the primary sensory cortex

Question 15

What are Aδ-fibres?

Answer 15

Mechanical/thermal nociceptors that are thinly myelinated, respond to noxious/mechanical and thermal stimuli; mediate ‘first’, or fast, pain

Question 16

What is the spinothalamic tract?

Answer 16

Ascending pathway of the spinal cord involved in pain perception (location, intensity)

Question 17

Define transmission with relevance to pain

Answer 17

Propagation of pain signal as nerve impulses through the nervous system

Question 18

Define perception with relevance to pain

Answer 18

Conscious experience of pain, causes physiological and behavioural responses