Wk 4 Pain Pathophysiology Flashcards
Acute pain is protective
teaches avoidance
3 parts of nervous system involved in pain
Afferent pathways, interpretive centers, efferent pathways
Pathway that starts in the peripheral system that sends signal to spine then to brain
Afferent pathways
Interpretive centers
cortical and subcortical areas of the brain (brainstem, midbrain, and cerebral cortex)
Take message from interpretive system back down and to peripheral system and elicit a response to the pain
Efferent pathways
Process of feeling pain, or any sensation
nociception
Free nerve endings in afferent peripheral nervous system
nociceptors
Nociceptor pain is pain that is close to
causing an injury
With low intensity
nociceptors may not be activated
Nociceptors
Skin, dental, periosteum, meninges, some internal organs
There are no nociceptors in the
brain, alveoli, deep tissues
Neurotransmitters regulate control related to the __ of pain impulse
transmission
Natural neurotransmitters that aid in inhibiting pain
Endorphins
Where painful stimuli is converted to an action potential
Transduction
Transduction occurs along
A-dela and C fibers
Prostaglandins when activated __ pain threshold
lower
A-delta are small diameter
myelinated, rapid acting
A-delta pain is
localized and sharp/stinging
C fibers are small diameter
unmylinated, slow pain
C fibers are
dull, burning, aching, poorly localized
A-alpha and A-beta fibers are
large and do not transmit pain
Action potentials move from periphery to spinal cord and brain
Transmission
What fibers are responsible for transmission?
A-delta and C fibers
Brain receives signal and interprets them as painful
perception
Perception is influenced by
attention, distraction, anxiety, fear, fatigue, previous experiences and expectations
Conscious perception of pain occurs primarily in
limbic and reticular systems of the brain
Greatest intensity of pain that a person can handle, varies over time
Pain tolerance
Lowest amount of pain that a person can recognize, perceptional dominance occurs
Pain threshold
Someone who hasn’t slept, isn’t feeling, good, their pain tolerance will be
lower
Intense pain in one location may increase the threshold in another location
perceptional dominance, ex: pain at one sit masks pain at another site
Opioid tolerance
reduced drug effect after repeated exposure
Endorphins modulate
presynaptic transmission
We can change how the brain modulates pain
synaptic transmission of impulses is altered
Morphine mimics the
endogenous effect of endorphins
If we block the pain before if gets to the pain we can lower pain perception
Gate control therapy
Distraction is gate control theory
Your brain will only process A-aphla and A-beta instead of A-delta and C fibers
Nociceptors when activated stimulate
chemical mediators that are part of the inflammatory response
These chemical mediators are called
Histamine, prostaglandins, leukotrienes.
Archiadonic acid metabolite cause the
inflammatory mediators
Prostaglandins promotes
inflammation, pain, fever
Prostaglandins also,..
protect lining of stomach from acid, promote blood clotting and dilate blood vessels to kidneys
Acute pain or nociceptor pain lasts
seconds to 3 months
chronic pain leads to changes in the
CNS and PNS, dysregualtion of nocicreceptors
Often no __ response in chronic pain
ANS
Chronic pain has more
emotional involvement
Stimulus outside, peripheral pain
nociceptive pain
Pain within the CNS, lesion or injury to nerve themselves
neuropathic pain
Neuropathic pain doesn’t respond to
usual pain medications
cutaneous nociceptive pain
skin, muscular, sharp pain that’s localized
visceral nociceptive pain
organ pain, cramping, diaphoresis, not localized, radiates
Examples of neuropathic pain
diabetic neuropathy, tumor, nerve suppression, phantom limb pain
Pain felt at a distance form the actual site
referred pain, common in visceral pain
Phantom pain is most intense
right after the amputation, but does resolve over time
