Chapter 14- Pain and Temperature Flashcards
1
Q
What is pain?
A
Dysfunctions of general or specific senses that cannot be defined, identified or measured by an observer
2
Q
What kind of phenomenon is pain?
A
Unpleasant but a protective phenomenon
3
Q
Pain: Complex?
A
Interactions between physical, cognitive , emotional etc
4
Q
How did McCaffrey define pain?
A
“Whatever the experiencing person says it is, existing whenever they say it does”.
5
Q
What can pain and variations in temperature signal?
A
Disease
6
Q
What is a common manifestation of temperature dysfunction?
A
Fever
7
Q
What is often the first symptom of infectious or inflammatory conditions?
A
Temperature changes
8
Q
What are the 3 Theories of Pain?
A
- Specificity theory
- Gate Control theory
- Neuromatrix theory
9
Q
What is the specificity theory?
A
Injury activates specific pain receptors in the brain. Intensity of pain is directly related to associated tissue injury.
-Pricking one’s finger = minimal pain
-Cutting hand with a knife = more pain
10
Q
What is the problem with the specificity theory?
A
Does not account for persistent, emotional pain
11
Q
What is the Gate control Theory?
A
Combines and builds upon theories to explain multidimensional aspects of pain.
Pain transmission is altered by a balance of signals sent to spinal cord where cells work as a “gate”
Spinal gate controls pain transmission to higher centres in CNS
12
Q
What is the Neuromatrix theory?
A
Brain produces patterns of nerve impulses draw from various inputs (genetic, psychological, cognitive). However pain can be felt without them, like phantom limb. Therefore stimuli may trigger the patterns but do not produce them.
13
Q
What are the 3 portions of the nervous system responsible for (in relation to pain)?
A
Pain perception, sensation and response
14
Q
What are the 3 portions of the nervous system involved in perceiving pain?
A
- Afferent pathway
- Interpretive centres CNS
- Efferent pathways
15
Q
What is Nociception?
A
processing of harmful (noxious) stimuli through nervous system
16
Q
What are Nociceptors?
A
Pain receptors
17
Q
What kind of nerve endings do Nociceptors have?
A
Free nerve endings in afferent PNS
18
Q
What are the 2 types of nociceptors?
A
A delta fibers
C fibers
19
Q
What are A delta fibres?
A
Large, myelinated that access large tracts in spinal cord
20
Q
What are C fibers?
A
Smaller, unmyelinated that access smaller tracts in spinal cord
21
Q
What pain is perceived by A delta fibres?
A
Fast sharp pain
22
Q
What pain is perceived by C fibres?
A
Dull, throbbing pain
23
Q
What kind of pain is perceived first? And what pain follows it?
A
Fast sharp pain is perceived first, followed by dull, throbbing pain
24
Q
What is a transducer?
A
Device that converts variations into an electrical signal
25
What is Transduction?
Activation of nociceptors
26
What is Transmission?
Conduction to dorsal horn and up in spinal cord
27
What are the 3 systems of pain perception?
1. Sensory-discriminative system
2. Motivational-affective system
3. Cognitive-evaluative system
28
What is the sensory-discriminative system?
Identifies presence, location and intensity (somatosensory cortex)
29
What is the Motivational-affective system?
Determines avoidance and emotional responses (reticular formation, limbic system)
30
What is the Cognitive-evaluative system?
Learned pain experience (can therefore modulate perception of pain)
31
What is pain perception?
Conscious awareness of pain
-Reticular and limbic system
32
What is Pain threshold?
Lowest intensity of pain that a person can recognise
33
What is Pain tolerance?
Highest intensity of pain a person can endure.
-Varies among people and in same person over time
34
How does pain tolerance decrease?
Decreases with repeated exposure
35
What is perceptual dominance?
Intense pain at one location may increase threshold (lower pain perception) in another location
36
What is pain modulation?
Different mechanisms act to increase or decrease pain transmission through nervous system
37
What peripheral triggering mechanism initiates excitatory neurotransmitters?
Tissue injury
Chronic inflammation
38
What are examples excitatory neurotransmitters?
Substance P
Glutamate
Histamine
Prostaglandins
39
What do excitatory neurotransmitters do to nociceptors?
Reduce nociceptors activation threshold, increasing the nociceptors' responsiveness
40
What are examples of inhibitory neurotransmitters?
Opioids
GABA
Cannabinoids
Serotonin
Norepinephrine
41
What do inhibitory neurotransmitters do to pain?
Inhibit/reduce transmission of pain signal
42
What are endorphins?
Combination of "endogenous" and "morphine"
-Opiod neuropeptides
43
What is transmitted from the brain to inhibit pain signal?
Descending inhibitory impulse
44
What kind of receptors are Opiate receptors?
G protein coupled receptors
45
What do morphine-like neuropeptides bind with throughout the body?
Opiod receptors
46
What happens when opioid receptors bind with morphine-like neuropeptides?
Pain impulses in periphery, spinal cord and brain are inhibited
47
What are morphine-like neuropeptides responsible for?
Well-being
48
What does cannabis produce?
Resin containing cannabinoids
49
Cannabinoids are ________ in humans
Analgesic (relieve pain)
50
What are the drawbacks of cannabinoids?
Psychoactive
Addictive
51
When were cannabinoids legalised in Canada?
2020
52
What are Endocannabinoids?
Synthesised in body from phospholipids that modulate pain
53
How does alcohol reduce pain?
Alcohol depresses CNS, slowing down the brain and NS which delivers some pain relief
54
What was the method of pain relief in 1200-1500 England?
-Potion called "Dwale" for anesthetic
Ingredients; Alcohol-based, bile, opium, lettuce, hemlock (toxic plant) and vinegar
55
What was created in 1840 for pain relief?
Ether
56
What happened in 1846 in amphitheatre of Massachusetts General Hospital?
First pain-free surgery was preformed
57
What kind of pain is Acute pain?
Nociceptive
58
What is acute pain?
Protective mechanism that alerts to harmful condition and mobilises person to relieve it.
59
How long does acute last?
Minutes to weeks
60
What 3 areas does acute pain arise from?
1. Somatic
2. Visceral
3. Reffered
61
What parts of body is somatic acute pain?
Skin
Joints
Muscles
62
Is somatic acute pain localised?
Very localised
63
What fibres are involved in somatic acute pain?
A delta = Sharp, well localised
C fibers = Dull throbbing
64
What parts of body is visceral acute pain?
Internal organs
Lining of body cavities
65
Is visceral acute pain localised?
No. It's poorly localised
66
What fibres are involved in visceral acute pain?
C fibers: Aching, throbbing pain
67
What is referred acute pain?
Pain is felt distant from point of origin
68
What receptors are involved in referred acute pain?
Cutaneous
Visceral
69
Where do referred acute pain receptors converge and what is the result of this?
On same ascending neuron
-Brain can't distinguish between the two receptors
70
Where is pain often referred to ?(referred acute pain)
Skin area
71
Why is pain often referred to the skin?
Because skin has more receptors
72
What kind of pain is persistent pain?
Intractable pain
73
What is persistent pain?
Pain that lasts more than 3-6 months (beyond expected healing time)
74
What is the purpose of persistent pain?
Serves NO purpose
-Poorly understood too
75
What are the kinds of persistent pain?
Ongoing e.g back pain
Intermittent e.g migraines
76
How does a change in the brain affect persistent pain?
Change in brain = reduced ability to cope with pain
77
What causes neuropathic pain?
Dysfunction of nervous system caused by long term changes in pain pathway and abnormal processing
78
What kind of pain is neuropathic pain?
Chronic/ amplification of pain
79
How is neuropathic pain described?
As burning, shooting, shock-like or tingling
80
What is neuropathic pain characterised by?
Increased sensitivity to painful and NON-painful stimuli with hyperalgesia
81
What is hyperalgesia?
Increased capacity to feel pain
82
What is analgesia?
Absence of pain
83
What is a fever?
Temporary resetting of hypothalamic thermostat to a higher level in response to exogenous or endogenous pyrogens
84
Pyrogens
Substance hat produces fever when released into blood
85
What are exogenous pyrogens?
Pathogens
86
What do exogenous pyrogens cause the release of?
Endogenous pyrogens
87
What are endogenous pyrogens?
TNF-a
IL-1
IL-6
88
How do pyrogens raise the thermal set point?
By inducing hypothalamus synthesis of prostaglandin E2 (PGE2)
89
What does Pyro mean?
Related to fire
90
What is Prostaglandins effect on temperature/fever?
Increase temperature through increased heat production and conservation
91
When prostaglandins are in effect during a fever, how does the individual feel?
Feels colder, curls up to decrease body surface area, goes to bed to get warm
92
How is heat conserved during a fever to make the individual feel cold?
Cutaneous vasoconstriction
93
The increased body temperature is maintained until the fever ______?
Breaks and original set point is reinstated
94
When the original set point is reinstated during a fever, how does the individual feel?
Feels warm, throws off covers and stretches out
95
How does the ANS react to production of PGE2 raising the thermostatic set point?
Heat conservation or heat generation aka fever
96
What does the ANS do to conserve heat?
Cutaneous vasoconstriction
Decreased sweating
97
What does the ANS do to generate heat?
Increased muscle contraction
Shivering reflex
Increased metabolism
98
What does the raised temperature produced by a fever do to microorganisms?
Kills many of them and adversely affects their growth and replication
99
What does the raised temperature produced by a fever do to bacterial replication?
Decreases serum levels of minerals e.g Iron needed for bacterial replication
100
What does the raised temperature produced by a fever do to viral replication in infected cells?
Prevents viral replication by causing lysosomal breakdown
101
What does the raised temperature produced by a fever do to immune response?
It facilitates immune response
102
What does the raised temperature produced by a fever do to phagocytosis and interferon?
Phagocytosis is enhanced and antiviral interferon is augmented
103
Can suppression of fever be effective?
Yes, but should be used with caution
104
What are some disorders of temperature regulation?
1. Hyperthermia
2. Heat cramps
3. Heat exhaustion
4. Heat stroke
5. Hypothermia
6. Tissue hypothermia
7.Therapeutic hypothermia
105
What is hyperthermia?
Elevation of body temp without an increase in hypothalamic set point
106
What can hyperthermia produce?
Nerve damage
Coagulation of cell proteins
Death
107
What are heat cramps?
Severe spasmodic cramps in the abdomen and extremities
108
What do heat cramps follow?
Prolonged sweating and associated sodium loss (40-60mmol of sodium/litre of sweat)
109
Heat cramps are common in which individuals?
Individuals not accustomed to heat or performing strenuous work in warm climates
110
Signs/symptoms of heat cramps?
Increased core temp
Rapid pulse
Increased blood pressure
111
What is heat exhaustion?
The result of prolonged high core or environmental temperatures
112
What does heat exhaustion lead to?
Profound vasodilation and profuse sweating which causes dehydration, hypotension and tachycardia
113
How does heat exhaustion manifest?
Dizziness
Weakness
Nausea
Confusion
114
Heat stroke is potentially ______?
Lethal
115
What occurs if someone with heat stroke reaches 41°C?
Nerve damage and convulsions
116
What occurs if someone with heat stroke reaches 43°C
Death
117
What is the normal core body temperature?
37°C
118
What is the core body temperature of someone who is hypothermic?
Less than 35°C
119
What happens to the cells of someone with Hypothermia?
Ice crystals are produced inside cells causing cellular rupture
120
What is tissue hypothermia?
Slows cellular metabolism rate
Increases blood viscosity
Facilitates blood coagulation and vasoconstriction
121
What is therapeutic hypothermia?
Used to slow metabolism to preserve ischemic tissue during surgery
122
What is the risk associated with therapeutic hypothermia?
May lead to ventricular fibrillation and cardiac arrest
123
What are the pain facilitators?
Glutamate
Substance P
Histamine
Prostaglandin
Bradykinin
124
What are the pain inhibitors?
Opioids
GABA
Cannabinoids
Serotonin
Norepinephrine
