Test 3: 37 pain Flashcards
nociception
the sensory nervous system’s response to a harmful or potentially
harmful stimuli
pain vs nociception
Nociception– the sensory nervous system’s response to a harmful or potentially harmful stimuli
Pain – nociception + perception (needs consciousness)
acute pain
last less than 3 – 6 months, and/or is directly related to tissue damage. Short duration and gradually resolves as injured tissues heal.
chronic pain
extends beyond the expected period of healing (long duration), is not related to resolving injury, has no useful purpose, and is refractory to treatment.
abnormally increase in sensitivity to pain (“what hurts, now hurts a lot more”)
Hyperalgesia
triggering of a pain response from a stimuli that do not normally provoke pain (“what should not hurt, now hurts”)
allodynia
tranduction of pain
change of noxious stimuli into electrical impulse
transmission of pain
- Propagation of impulse through the nervous system
- A-delta fibers – myelinated, fast speed, sharp pain
- C fibers – unmyelinated, slow speed, longer-lasting, dull, diffuse pain
what kind of pain fibers for dull, diffuse pain
C fibers: unmyelinated, slow speed, longer-lasting, dull, diffuse pain
what find of pain fibers for sharp pain
A-delta fibers: myelinated, fast speeds, sharp pain
how does modulation of pain work
in spinal cord- will change the pain tranmission
activate descending analgesic systems: opioids, serotonin, NE
perception of pain is by
Integration of thalamocortical, reticular, and limbic function to produce final conscious subjective and emotional experience
3 neuron pain pathway simply is
First Order
* Originates in the periphery and projects to the spinal cord- primary afferent fiber
Second order
* Ascends to the spinal cord
Third order
* Projects into the cerebral cortex and other supraspinal structures
how do TRP work
Transient receptor potential (TRP) vanilloid / capsaicin (TRPV1)
- TRP are activated and allow calcium influx into the 1st order neuron, activating an action potential
- Acute pain – receptor turns off as soon as the stimulus is gone
- Chronic pain – receptors don’t turn off, and activating substances persist : Substance P, Calcitonin gene-related peptide, Potassium ions and Inflammatory mediators
lamina V contain — neurons that are able to respond to both — and —
wide dynamic range
noxious and non noxious stilumi
can be involed in wind up pain and the development of chronic pain
what does plasticity in the dorsal horn mean
can modify the pain stimuli depending on the type and strength of signal input
gate control theory
“Trick the nervous system to block painful stimuli transmission by sending non- painful stimuli”
when you hurt an area, you rub it, that rubbing will decrease painful signal
antinociceptive system of the brain tries to decrease pain by —
releasing
* Endorphins (endorphin, enkephalin, and dynorphin)
* Serotonin
* norepinephrine
inhibits transmission in spinal cord pain pathway at the dorsal horn
how does limbic system effect pain
limbic system will assign an negative emotional value to a painful experience
- pain hurts, avoid it
why is acute pain important
occurs when there is tissue damage and resolves when healed
- Serves to alter animal behavior in order to avoid or minimize damage
- Protective mechanism
two types of acute pain
nociceptive pain: radicular, somatic, visceral
inflammatory pain
what types of nociceptive acute pain
Caused by the detection of (potential) harmful stimuli around the body by
nociceptors
- Radicular pain – from nerve root irritation
- Somatic pain – from tissues such as muscle, bone, or skin
- Visceral pain – from internal (hollow) organs
Pain originated from an insult to the integrity of tissues at the cellular level
inflammatory pain
type of acute pain caused by release of inflammatory mediators and recruitment of inflammatory cells
neuroplasticity
- Continuous process of short-, medium, and long-term remodeling of the neurosynaptic organization of the spinal
cord and brain - Ability to adapt to change
- Can be positive or negative changes for the wellbeing
what is central sensitization
wind up
in responce to chronic pain, body will lower the threshold needed to cause pain
↑ activation of NMDA (glutamate) channels= ↑ excitability
Recruitment of silent nociceptors → hyperreactivity of 2nd order neurons in the spinal cord → recruitment of WDR neurons to function as pain transmitters (very difficult to turn off once activated)
results in hyperalgesia and allodynia
central sensitization will cause the recruitment of —
silent nociceptors
central sensitization results in — and —
Hyperalgesia – abnormally increase in sensitivity to pain (“what hurts, now hurts a lot more”)
Allodynia – triggering of a pain response from a stimuli that do not normally provoke pain (“what should not hurt, now hurts”)
what are some simple pain scores
visual analogic scale (VAS): line with dash at pain scale
numeric rate: 1 out of 10
simple categorical scores: 1-3 mild, 4-6 moderate
mulidimensional pain scores include
physiologic and behavior signs
