Chapter 14 - Pain And Temperature Flashcards
Pain
Dysfunctions of general or specific senses
Pain is unpleasant but
A protective phenomenon
Pain cannot be
Defined, identified or measured by an observer
Pain is complex
Interactions between physical, cognitive, emotional etc
McCaffery defined pain as
Whatever the experiencing person says it is, existing whenever they say it does
Temperature
Like pain, variations in temperature can signal disease
Fever
A common an infestation of dysfunction
-often first symptom of infectious or inflammatory conditions
Specificity theory of pain: what activates specific pain receptors to the brain?
Injury
Specificity theory of pain: intensity is related to
Tissue injury
Specificity theory of pain: pricking finger vs cutting hand with knife
Pricking finger = minimal pain
Cutting hand with knife = more pain
Specificity theory of pain: problem with this theory
It does not account for persistent, emotional pain
gate control theory of pain
Combines and builds upon theories to explain multidimensional aspects of pain
gate control theory of pain: pain transmission
Is altered by a balance of signals sent to spinal cord where cells work as a gate
gate control theory of pain: spinal gate controls
Pain transmission to higher centers in CNS
Neuromatrix theory of pain:
Brain produces patterns of nerve impulses drawn from various inputs
-including: genetic, psychological and cognitive experiences
Neuromatrix theory of pain: phantom limb
Believes that pain can be felt without experiencing them
Neuromatrix theory of pain: does stimuli produce pain?
Stimuli may trigger the patterns but does not produce them
Three portions of nervous system responsible for pain perception, sensation and response
- Afferent pathway
- Interpretive centers (CNS)
- Efferent pathways
Nociception
Processing of harmful (noxious) stimuli through nervous system
Nociceptors are ___ nerve endings found in
-free
-afferent PNS
Two types of nociceptors
A delta, C fibres
A delta fibres
Large and myelinated
-access large tracts in spinal cord
C fibres
Smaller and unmyelinated
-access smaller tracts in spinal cord
Fast sharp pain is what type of fiber
A delta fibres
-usually perceived first
Dull throbbing pain
C fibres
-followed by a dull throbbing pain
Transduction
Activation of nociceptors
Transmission
Conduction to dorsal horn and up spinal cord q
Sensory discriminative system
Identifies presence, location, and intensity
Sensory discriminative system is found
Somatosensory cortex
Motivation affective system
Determines avoidance and emotional responses
Motivation affective system is found
Reticular formation-> limbic system
Cognitive evaluative system
Learned pain experience
Cognitive evaluative system can therefore…
Modulate perception of pain
Transducer
Device that converts variations into electrical signal
Slow pain travels toward
-brain stem reticular formation
-thalamus
-somatosensory cortex
Fast pain travels
-thalamus
-somatosensory cortex
Pain perception
Conscious awareness of pain
Pain perception takes place in
-reticular and limbic system
Pain threshold
Lowest intensities of pain that a person can recognize
Pain tolerance
Highest intensity of pain a person can endure
-varies
-generally decreases with repeated exposure
perceptual dominance
Intense pain at one location may increase threshold in another location
Example: stubbed your toe, then someone punches your face, you will feel your jaw>the toe
Pain modulation
Different mechanisms act to increase or decrease pain transmission through nervous system
Peripheral triggering mechanism can Initiate excitatory neurotransmitters include
Tissue injury and chronic inflammation
Excitatory neurotransmitters
-substance P
-glutamate
-histamine
-prostaglandins
Function of excitatory neurotransmitters
Reduce nociceptors activation threshold = increased responsiveness of nociceptors
Inhibitory neurotransmitters
-opioids
-GABA
-cannabinoids
-serotonin
-norepinephrine
Inhibitory neurotransmitters function
Inhibit/reduce transmission of pain signal
Descending pathway and endorphins response
Transmitted from brain to inhibit pain signal
-combination of endogenous and morphine
Opiate receptors are ___ receptors for endorphins which are …
G proteins coupled receptors for endorphins which are opioid neuropeptides
Morphine like neuropeptides bind with
Opioids receptors throughout body to inhibit pain impulses in peripheral, spinal cord and brain
Morphine like neuropeptides are responsible for
Sensations of wellbeing
Cannabinoids
-cannabis—> resin containing cannabinoids
-analgesic
Drawbacks of cannabinoids
Psychoactive and addictive properties
When was cannabis legalized in Canada
2020
Endocannabinoids
Synthesized in body form phospholipids
-modulates pain
Alcohol pain reduction
-depressing CNS
-slows down brain and ns
-certain amount of pain relief
1200 to 1500 England: Dwale
Alcohol based, bile, opium, lettuce, hemlock (toxic plant) and vinegar
what was used in 1200 to 1500 as anesthetic
Dwale
1840 what was created for pain relief
Ether
1846 pain relief milestone
The first pain free surgery performed in amphitheater of massachusetts GH
Acute pain is otherwise known as
Nociceptors pain
Acute pain
-protective mechanism to alert of harmful condition
-mobilizes person to relieve it
-lasts min/weeks
acute pain arises from three areas
- Somatic
2.visceral - Referred
Acute somatic pain
-skin, joints, muscles, very localized
-sharp (A) and dull (C)
-well localized
Acute visceral pain
Internal organs and lining of body cavities
-poorly localized
-aching throbbing quality to pain
- C fibres
Acute referred pain
Distant from point of origin
-both cutaneous and visceral receptors converge on ascending neuron —> brain cannot distinguish the two
-since skin has more receptors, pain is often referred to a skin area
Persistent pain is also known as
Intractable pain
Persistent pain
More than 3-6 months
-no purpose/misunderstood
Example: ongoing back pain, or intermittent migraines
Studies with persistent pain
Change in brain = reduced ability to cope with pain
Cause of Neuropathic pain
Dysfunction of nervous system = long term changes in pain pathway and abnormal processing
Neuropathic pain
Chronic amplification of pain
-burning, shooting, chock like or tingling
Neuropathic pain is characterized by
Increased sensitivity to painful and non painful stimuli with hyperalgesia (increased)
Algesia
Capacity to feel pain
Analgesia
Absence of pain
Fever definition
Temporary resetting of hypothalamic thermostat to a higher levels in response to exogenous or endogenous pyrogens
Pyrogen
Substance that produces fever when released into blood
Exogenous pyrons
Cause release of endogenous pyrogens
Examples of exogenous pyrogens
TNFa, IL1, IL6
Pyrons raise… by inducing…..
-thermal set point
-hypothalamic synthesis of prostaglandin E
Prostaglandins effect
Increases temperature through increased heat production and conservation
Individual: feels colder, curls up to decrease body surface area, goes to bed to get warm
Cause:
Heat conservation through cutaneous vasoconstriction
Inc body temp is maintained until
Fever breaks and original set point is reinstated
-Indian fgeels warm, throws off covers and stretches out
Heat conservation
-cutaneous vasoconstriction
-decreased sweating
Heat generation
-inc muscle contraction
-shivering reflex
-inc metabolism
Benefits of fever
-kills microorganisms (affects their growth/replication)
-Dec serum levels of minerals
-lysosomal breakdown
-immune response
-enhances phagocytosis and interferon is augmented
Hyperthermia
Elevation of body temperature without an increase in hypothalamic set point
Hyperthermia risks
Can produce nerve damage, coagulation of cell proteins and death
Heat cramps
Severe spasmodic cramps in abdomen and extremities
-follows sweating
-sodium loss (40-60)
Heat cramps are common in individuals who are
Not accustomed to heat or performing strenuous work in warm climates
S/S of heat cramps
Inc core temp, rapid pulse, inc bp
Heat exhaustion
Result of prolonged high core or environmental temperatures
-vasodilation and sweating
risk of heat exhaustion
-dehydration, hypotension, tachycardia
Manifestations of heat exhaustion
Dizziness, weakness, nausea, confusion
Heat stroke
Potentially lethal
Heat stroke: 41
Nerve damage, convulsions
Heat stroke: 43
Death
Normal core body temperature is
37
Hypothermia
Body temp less than 35
Hypothermia produces
Ice crystals inside cells causing cellular rupture
Tissue hypothermia
-slows cellular rate
-inc blood viscosity
-facilitates blood coagulation
-vasoconstriction
Therapeutic hypothermia
Used to slow metabolism and preserve ischemic tissue during surgery
Risk of therapeutic hypothermia
May lead to ventricular fibrillation and cardiac arrest
