Physiology of Pain 05/10/18

Question 1

Why is pain difficult to assess?

Answer 1

It is very subjective

Question 2

What is the time period for pain to be termed chronic?

Answer 2

Over 3 months

Question 3

What age group is chronic pain highest in?

Answer 3

Over 65s

Question 4

What is pain?

Answer 4

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

Question 5

What are the 4 processes in the physiology of pain?

Answer 5

Transduction
Transmission
Modulation
Perception

Question 6

What is transduction?

Answer 6

Translation of noxious stimulus into electrical activity at the peripheral nociceptor

Question 7

What is transmission?

Answer 7

Propagation of pain signal as nerve impulses through the nervous system

Question 8

What is modulation?

Answer 8

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

Question 9

What is perception?

Answer 9

Conscious experience of pain

Causes physiological and behavioural responses

Question 10

What are Nociceptors?

Answer 10

Type of free nerve ending

Outgoing sensory neurones

Question 11

How are nociceptors activated?

Answer 11

Intense noxious stimuli

Question 12

What order of neurone is a nociceptor and what does it relay information to?

Answer 12

First order neurones

relays to second order neurones in the CNS

Question 13

How do 1st order neurones transfer information to 2nd order neurones?

Answer 13

Chemical synaptic transmission

Question 14

What is the nociceptive pathway?

Answer 14

Noxious stimuli acts on the free nerve ending
Creating an action potential along the 1st order neurone
Synapses with the second order neurone in the dorsal horn of the spinal cord
Axon is projected out

Question 15

What are the neurotransmitters in the N pathway?

Answer 15

Glutamate and peptides
Substance P
Neurokinin A

Question 16

Whwere do 2nd order neurones ascend?

Answer 16

In the anterolateral systen and terminate in the thalamus

Question 17

What are the 2 main components of the anterolateral system?

Answer 17

Spinothalmic tract

Spinoreticular tract

Question 18

What is the spinothalmic tract involved in?

Answer 18

Perception of pain

Question 19

What is the spinoreticular tract involved in?

Answer 19

Autonomic responses to pain, arousal, emotional responnses and fear of pain

Question 20

What are the two types of nociceptor?

Answer 20

A delta fibres

C fibres

Question 21

What do A-delta fibres respond to?

Answer 21

noxious mechanical and thermal stimuli

Mediate fast pain

Question 22

What do the C fibres respond to?

Answer 22

Poly modal
All noxious stimuli
Mediate slow pain

Question 23

What are four ways of classifying pain and some examples?

Answer 23

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

Question 24

What does nociceptive pain represent?

Answer 24

Normal response to injury of tissues by noxious (damaging) stimuli

Question 25

What provokes nociceptive pain?

Answer 25

Intense stimulation by noxious stimuli

Question 26

Is nociceptive pain adaptive?

Answer 26

Yes

Question 27

What is the function of nociceptive pain?

Answer 27

Early warning physiological protective system to detect and avoid noxious stimuli

Question 28

What causes inflammatory pain?

Answer 28

Activation of the immune system by tissue injury or infection

Question 29

What is inflammatory pain activated by?

Answer 29

Variety of mediators released at the sit of inflammation by leucocytes, vascular endothelium and tissue resident mast cells

Question 30

What does inflammatory pain cause?

Answer 30

Heightened pain sensitivity to noxious stimuli (hyperalgesisa) and pain sensitivity ti innocuous stimuli (allodynia)

Question 31

What does inflammatory pain discourage?

Answer 31

Physical contact Discourages movement of inflammed part

Question 32

Is inflammatory pain adaptive?

Answer 32

Yes

Question 33

What are two types of pathological pain?

Answer 33

Neuropathic or Dysfunction

Question 34

What is neuropathic pain caused by?

Answer 34

Damage to neural tissue

Question 35

What are examples of neuropathic pain?

Answer 35

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

Question 36

What can neuropathic pain be percieved as?

Answer 36

Burning shooting Numbness Pins and needles

Question 37

What is dysfunctional pain?

Answer 37

No identifyable damage or inflammation

Question 38

What are examples of dysfunctional pain?

Answer 38

``` Fibromyalgia IBS Tension headache Temporomadibular joint disease Interstitial cystitis ```

Question 39

Are simple analgesics effective in pathological pain?

Answer 39

No

Question 40

What can sometimes treat pathological pain?

Answer 40

Anti-depressants Anti-epileptics Opioids

Question 41

Is pathological pain protective?

Answer 41

No | It is maladaptive

Question 42

What is referred pain?

Answer 42

Pain developed in one part of the body is felt by another

Question 43

What types of pain can be felt as referred pain?

Answer 43

Deep | Visceral

Question 44

What is referred pain caused by?

Answer 44

Convergence of nociceptive visceral and skin afferents upon the same spinothalmic neurons at the same spinal level

Question 45

What are some examples of referred pain?

Answer 45

Liver pain felt in shoulder Heart pain felt in arm and jaw Appendix pain felt in central stomach/umbilical region