Lecture 7 (Exam 2) - Pain Pathways-Brooke's Deck Flashcards
The increased responsiveness of peripheral neurons responsible for pain transmission to heat, cold, mechanical or chemical stimulation is called ____?
Sensitization
(Slide 18, pg. 370 Stoeltings)
The release of _________ mediators and adaptation of signaling pathways in primary sensory neurons induced by noxious stimuli causes sensitization.
This process usually resolves as tissues heal and the peripheral sensitization diminishes. ________ pain occurs when this does NOT happen.
inflammatory; Chronic
(Slide 18, pg 370 Stoeltings)
Increased pain sensations to normally painful stimuli is called ______?
Perception to pain sensations in response to normally non-painful stimuli is called _______?
Hyperalgesia
Allodynia
(Slide 18, pg 370 Stoeltings)
This type of hyperalgesia occurs at the original site of injury from heat and mechanical injury. Creates a decreased pain threshold, increases response to suprathreshold stimuli, spointaneous pain, and expansion of receptive field? ____________
This type of pain is characterized by the uninjured skin surrounding the injury and sensitization of central neuronal circuits? (mechanical only) ____________
Primary hyperalgesia. (Heat & Mechanical)
Secondary hyperalgesia. (only mechanical)
*remember this is describing pain at the PERIPHERAL level
(Slide 19, pg. 371-372)
When pain enters the spinal cord and travels to the brain, it changes from peripheral pain to _______ _____!
Central pain!
(Slide 20)
What is the relay center in the spinal cord for nociceptive & other sensory activity?
The Spinal Dorsal Horn
Slide 20
Pain signals use ________ pathways to reach the brainstem and forebrain (SI and SII).
What does SI and SII stand for and what does this structure do?
Afferent
SI (primary somatosensory)
SII (secondary somatosensory)
Accounts for the perception of pain location and intensity (the discrimination of pain stimuli)
(Slide 20, pg. 372 Stoeltings)
Is the dorsal root ganglia peripheral or central?
Which fibers are myelinated?
Unmyelinated?
DRG = peripheral (the dorsal root is central)
Mylelinated = A beta, A delta
Unmyelinated = C fibers
(Slide 21, pg 373 Stoeltings)
Lamina I (marginal layer) and lamina II (substantia gelatinosa) are innervated by _____ fibers.
C fibers
(slide 21)
What are the laminae and area that become desensitized/affected with spinal/subarachnoid or epidural agents (Ketamine, opioids, or local anesthetics)?
Laminae I, II, III, IV, VII and NKI (Neurokinin-1) receptor
(Slide 21)
Which lamina do opioids work on specifically?
Lamina II (substantia gelatinosa)
*says its on boards
(Slide 21)
The ventral horn and laminae ___, ___, ___ are innervated by _____ fibers that innervate the muscles and viscera, so this means they are also affected from our anesthetic agents.
Both the dorsal and anterior section will be affected.
I, IV, Vll
Myelinated fibers
(Slide 21)
Laminae III and IV, where the NKI (Neurokinin I) is with substance P, can be affected by spinals and epidurals, too.
T/F?
True!
(Slide 21)
What are the 5 excitatory Neuromodulators ( as in neurotransmitter) in in the CNS?
- Glutamate
- Calcitonin
- Neuropeptide Y
- Aspartate
- Substance P
(slide 28)
What are the 5 inhibitory Neuromodulators (Neurotransmitters) in the CNS?
- GABA
- Glycine
- Enkephalins
- Norepinephrine
- Dopamine
(slide 28)
Midazolam is most specific to this inhibitory neuromodulator (receptor and subunit) in the CNS: _____________
GABAa
(slide 28)
In the CNS, what are the 4 Ascending pathways of nociceptive information?
- Spinothalamic
- Spinomedullary
- Spinobulbar
- Spinohypothalamic
(slide 29)
What type of impulses and laminae are associated with the Spinothalamic tract? (STT)
Pain, temperature, and itch
Laminae I, VII, & VIII: All afferent fibers
(Projects directly to the thalamus)
(slide 29)
What type of impulses are associated with the Spinomedullary tract?
(direct projections to homeostatic control regions in the medulla and brainstem)
- pg. 376
What type of impulses and laminae are associated with the Spinobulbar (the hindbrain) tract?
Behavior component toward pain (Laminae I, V, & VII)
(direct projections to homeostatic control regions in the medulla and brainstem)
(slide 29)
What type of impulses and laminae are associated with the Spinohypothalamic tract? (SHT)
Autonomic, neuroendocrine, and emotional aspects of pain (Laminae I, V, VII, & X)
(direct projections to the hypothalamus and ventral forebrain)
(slide 29)
What are the 6 most commonly activated supra-spinal Modulation regions of the nociception?
(regions involved in nociceptive perception.
in the CNS)
FAT ICP
- Forebrain S I & S II (somatosensory)
- Anterior cingulate cortex (ACC)
- Thalamus
- Insular cortex (IC)
- Cerebellum
- Prefrontal cortex
“These brain regions form a cortical and subcortical network, which are critically involved in the formation of emotional aspects of pain and the central modulation of pain perception.” - pg. 377
(slide 30)
Forebrain S I & S II (somatosensory) receives input from where?
And is responsible for the perception of what?
Input from the Thalamus
Identifying location and intensity
- pg. 377
(slide 30)
The Supra-spinal modulator: Insular cortex (IC),
receives input from where?
And is responsible for the perception of what?
Input from the Thalamus
Responsible for emotional and motivational aspects of pain. (goes through the amygdala)
-pg. 377
(slide 30)
The Supra-spinal modulator: Thalamus
receives input from where?
Input from the dorsal horn
- pg. 377
(slide 30)
Once pain had been interpreted, it also must be acted upon. Which tract is responsible for this action?
Descending Inhibitory Tract
(slide 31)
What are the 3 supra-spinal Descending Inhibitory Tracts/pathways that promote and suppress nociceptive transmission through the dorsal horn of the CNS?
- Originate Periaqueductal gray (PAG)
- Neurotransmitters
- Hyperpolarize A-delta and C fibers
(slide 31)
The Originate Periaqueductal gray (PAG) of the supra-spinal modulation Descending Inhibitory Tract, inhibit activity of nocireceptors through these sites:
- The Rostral Ventromedial Medulla (RVM)
- Dorsolateral funiculus
- Synapse in dorsal horn
-pg. 378
(slide 31)
Which 3 Neurotransmitters of the supra-spinal modulation Descending Inhibitory Tract, inhibit activity of nocireceptors?
Endorphins
enkephalins
serotonin
(slide 31)
How does Hyperpolarized A-delta and C fibers of the Descending Inhibitory Tract, inhibit the activity of nocireceptors?
↓________________ ___
Opening ____ channels
Closing ____ channels
- Decrease release of substance P
- Opening of K+ channels/inhibition of Ca++ channels
- pg. 392
(slide 31)
The Descending Pathways of pain modulation in the CNS can either be Inhibitory (DI) or Faciliatory (FD) based on what factors?
- Other somatic stimuli
- Psychological factors (arousal, attention, and expectation)
(slide 32)
The PAG-RVM system contains what 3 opioid receptors and contributes to what 2 physiological pain sensations?
- µ, κ, δ opioid receptors
- hyperalgesia & Allodynia
(slide 32)
Where does the pain impulse originate if it is pertaining to the descending inhibitory tract?
PAG-RVM
(slide 34)
What two components does the pain include?
Sensory -discriminative - Ascending - perception of pain
Motivational- affective - responses to painful stimuli (e.g. attention, arousal, somatic/autonomic reflexes, endocrine or emotional changes)
(pain can be affected by physical, emotional, spiritual, or psychological)
Slide 3
Is sensory-discriminative ascending or descending?
Its ascending pathway
Slide 3
Describe the pathway of sensory-discriminative.
Nerve impulse at the site (Skin, muscles, or organs) –>spinothalamic and trigemino-thalamic tracts –> cerebral cortex(somatosensory cortex) –> perception of pain
Slide 3
What does motivational-affective response to painful stimuli include?
- Attention and
- Arousal
- Emotional
- Somatic and autonomic reflexes
- Endocrine responses (make sure endocrine and stress response system is adequate when we are experiencing pain)
Slide 3
Why is attention and arousal important in the context of pain management?
Lack of sleep makes us more irritable and susceptible to pain.
Slide 3
(Use a holistic approach of pain management like how your patient is sleeping, eating, or exercising. All of this affects the management of pain. )
Slide 3
What is Nociception?
It is part of the nervous system that protects from the response of harmful or potentially harmful stimuli.
Slide 4
What Kind of stimuli do specialized nerve endings like nociceptors detect?
mechanical
Chemical
Thermal
Slide 4
Besides nociception what other factor can influence the pain?
Biological factors
( It amplifies nociception signal to the brain–> nerve fibers are activated repeatedly –> brain decides that the body needs more stress sensors –>body becomes so sensitive to pain that with light touch body feels intense pain)
(slide 4)
Patient who has _____pain are more susceptible to pain related to B____ F_____.
Chronic pain
Biologic factors
(slide 4)
What defines chronic pain?
Pain lasting more than 3 months.
(Chronic pain outlasts the physical pain and is difficult to reverse if this continues to go.)
slide 4
According to the experiment, who experienced more pain? Children who believe that they had no control over pain or children who had some control?
Children who believed that they had no control over pain.
(psychological factor)
Slide 4
What are the location of Nociceptors we talked about in class?
Skin, muscles, joints, viscera, & vasculature.
(Slide 13)
If you get get stabbed🔪 in the leg, what would be the pathway the pain impulse would travel?
Hint: You start off with stimulus
Stimulus -> Nociceptor: Resting Threshold -> Transmission -> Modulation (where you rate your pain) -> Interpretation
(Slide 13)
Transduction - signal starts at nerve endings
Transmission - impulse travels to nerve body connection to DH
Modulation - Altering pain transmition mechanisms at DH
Perception - Thalamus (central relay center) then somatosensory cortex (discrimination of specific stimuli)