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 results from the presence of enhanced pain from heat AND mechanical injury.
This type 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 is 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 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 is with substance P can be affected by spinals and epidurals, too.
T/F?
True!
(Slide 21)
What are the 5 excitatory Neuromodulators in the CNS?
- Glutamate
- Calcitonin
- Neuropeptide Y
- Aspartate
- Substance P
(slide 28)
What are the 5 inhibitory Neuromodulators in the CNS?
- GABA
- Glycine
- Enkephalins
- Norepinephrine
- Dopamine
(slide 28)
What specific inhibitory Neuromodulator in the CNS is most specific to Midazolam?
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)
(direct projections 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 Modulations of the nociception?
(the regions involved in nociceptive perception.
in the CNS)
- Forebrain S I & S II (somatosensory)
- Anterior cingulate cortex (ACC)
- Insular cortex (IC)
- Prefrontal cortex
- Thalamus
- Cerebellum
“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)
The Supra-spinal modulator: Forebrain S I & S II (somatosensory) receives input from where?
And is responsible for the perception of what?
Input from the Thalamus
For the location and intensity of pain
- 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 modulation 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)
How does the Originate Periaqueductal gray (PAG) of the supra-spinal modulation Descending Inhibitory Tract, inhibit activity of nocireceptors?
- Through 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 supra-spinal modulation Descending Inhibitory Tract, inhibit activity of nocireceptors?
- 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
Motivational- effective
(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
somatic and autonomic reflexes
Endocrine responses (make sure endocrine and stress response system is adequate when we are experiencing pain)
Emotional changes
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?
-The experience of pain with a series of complex neurophysiologic processes
Slide 4
Medications target pain by actions of ?
Transduction, transmission, interpretation and modulation in PNS and CNS
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 ________.
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)