Physiology of pain

Question 1

What is the definition of pain?

Answer 1

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

Question 2

What are the 4 processes in the physiology of pain?

Answer 2

Transduction
Transmission
Modulation
Perception

Question 3

What is transduction?

Answer 3

Translation of noxious stimulus into electrical activity at the peripheral nocicpeto

Question 4

What is transmission?

Answer 4

Propagation of pain signal as nerve impulses through the nervous system

Question 5

What is modulation?

Answer 5

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

Question 6

What is perception?

Answer 6

Conscious experience of pain. Causes physiological and behavioural responses

Question 7

What is a nociceptor?

Answer 7

Specific primary sensory afferent neurones normally activated by intense noxious stimuli (e.g. mechanical, thermal or chemical)
First order neurones that relay info to second order neurones in CNS via chemical synaptic transmission

Question 8

What neurotransmittors are involved in the nociceptive pathway?

Answer 8

Glutumate and pepties (substance P and neurokinin A)

Question 9

Where is the cell body in the nociceptive pathway found?

Answer 9

Dorsal root ganglion

Question 10

Where will you find second order neurones?

Answer 10

In the anterolateral system

They terminate in the thalamus

Question 11

What is the spinothalamic tract?

Answer 11

Involved in pain perception (location, intensity)

Question 12

What is the spinoreticular tract?

Answer 12

Involved in autonomic responses to pain, arousal, emotional respones and fear of pain

Question 13

Where will the pain impulse go after the thalamus?

Answer 13

Sensory information is relayed (3rd order) to the primary sensory cortex

Question 14

What kind of stimulus can activate a noiceptive receptor?

Answer 14

Mechanical
Thermal
Chemical

Question 15

What are the different types of nocicpetors?

Answer 15

A-delta

C-fibres

Question 16

What is an A-delta fibre?

Answer 16

Mechanical/ thermal nociceptors that are thinly myelinated.
Respond to noxious mechanical and thermal stimulus
Mediate first/ fast pain

Question 17

What is a C-fibre?

Answer 17

Nociceptors that are unmyelinated
Collectively respond to all noxious stimulus
Polymodal
Mediate second/ slow pain

Question 18

What type of pain with A-delta fibres produce?

Answer 18

Lancinating
Stabbing
Prickling

Question 19

What type of pain will C-fibres produce?

Answer 19

Burning
Throbbing
Cramping
Aching

Question 20

How can pain be classified?

Answer 20

Mechanisms (nociceptive, inflammatory, pathological)
Time course (acute, chronic, breakthrough)
Severity (mild, moderate, severe)
Source of origin (somatic or visceral)

Question 21

What is nocicpetive pain?

Answer 21

Normal response to injury by noxious stimulus
Only provoked by an intense stimulus
Adaptive pain

Question 22

What is inflammaory pain?

Answer 22

Activation of the immune system by tissue injury or infection
Variety of mediators released at the site of inflammation by leucocytes, vascular endothelium and tissue resident mast cells
Adaptive - promotrs repiar until healing occurs

Question 23

What is hyperalgesia?

Answer 23

Heightened pain sensitivity to noxious stimuli

Question 24

What is allodynia?

Answer 24

Pain sensitvity to innocuous stimulus

Question 25

What causes neuropathic pain?

Answer 25

Damage to neural tissue

Question 26

What are examples of neuropathic pain?

Answer 26

``` Compression neuropathies Peripheral neuropathies Central pain Postherpetic neuralgia Trigeminal neuralgia Phantom limb ```

Question 27

What type of pain will neuropathic pain cause?

Answer 27

Burning Shooting Numbness Pins and needles

Question 28

What is dysfunctional pain?

Answer 28

No identifiable damage or inflammation

Question 29

What are some examples of dysfunctional pain?

Answer 29

``` Fibromyalgia Irritable bowel syndrome Tension headache Temprormandibular joint disease Interstitial cysititis ```

Question 30

What type of drugs can be used to treat dysfunctional pain?

Answer 30

Antidepressants | Anti-epileptics

Question 31

What are the 2 different types of pathological pain?

Answer 31

Neuropathic | Dysfunctional

Question 32

What is referred pain?

Answer 32

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

Question 33

Why does referred pain occur?

Answer 33

Convergene of nociceptive visceral and skin afferents upon the same spinothalamic neurones at the same spinal level

Question 34

Where can cardiac pain refer to?

Answer 34

Left arm and jaw

Question 35

Where can gall bladder and liver pain refer to?

Answer 35

Right shoulder

Question 36

Where can stomach/ pancreatic pain refer to?

Answer 36

Epigastric area

Question 37

Where can appendix pain refer to?

Answer 37

Umbilical area