Pain Flashcards
Two subtypes of Aδ fibers
Two subtypes of Aδ fibers
Type I Aδ- respond to dangerously intense mechanical and chemical stimuli, but have relatively high heat thresholds
Type II Aδ- more sensitive to noxious heat than mechanical and chemical stimuli
T/F the TRP channels are always selective
FALSE
Not Always Selective
T/F smelling mint can be painful
TRUE
Szalassi
TRPV1:
TRPA1:
1 and V3 by___
Szalassi
TRPV1: capsacin
TRPA1: cinnamon, horseradish, garlic
1 and V3 by menthol (mint)
which fibers tell if there is a threat
C fibers
i think
• Two different kinds of nociceptor fibers
• Aδ fibers and C fibers
*first pain fibers
sharp, Aδ fibers
which is faster Aδ fibers or C fibers
Aδ fibers are slightly faster I think
anterolateral system can be divided into
(i think): first pain and second pain
pain matrix
Pain is complex
Not singled layered
Our perception of pain is complex
Example: knowing something is going to hurt before it starts vs unexpected pain
Emotions, learning/memory, cognition, motor response… all of that has be integrated into our experience of pain
Honestly, there is a whole lot more to it
All of the brain structures involved in pain are collectively referred to as the pain matrix
• Once in the dorsal horn: the nociceptive axons synapse on second order neurons in laminae _____
• Once in the dorsal horn: the nociceptive axons synapse on second order neurons in laminae I, II, and V
• Once in the dorsal horn, C fibers (slow) synapse in second order neurons in laminae ____ and Aδ (faster) fibers synapse in ____
• Once in the dorsal horn, C fibers synapse in second order neurons in laminae I and II and Aδ fibers synapse in I and V
marginal zone
layer I of the laminae
Non-painful somatosensory stimuli synpase in second order neurons in laminae_____
Non-painful somatosensory stimuli synpase in second order neurons in laminae III, IV, and V
What is pain***
an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of tissue damage
T/F Nociceptors only discharge once the stimulus reaches a certain threshold
TRUE
• Nociceptors only discharge once the stimulus reaches a certain threshold
TRP receptors
allow cation flux into a nerve ending that leads to depolarization
-the channels in free nerve endings
second pain fibers **
• C fibers for delayed, diffuse, and longer-lasting pain
First vs second pain *
- First pain: sensory-discriminative
- Second pain: affective-motivational
- The sensory-discriminative dimension, often referred to simply as ‘intensity’ or given the label ‘sensory’, includes the spatial, and temporal characteristics and quality of pain.
- The pain experience includes motivational and affective aspects/components, such as negative emotions and arousal.
type of info for first vs second pain*
- First pain: Information about location, quality, intensity of the pain
- second pain: Fear and anxiety, the unpleasant feeling, and autonomic relationships happen through this pathway
first pain pathway
–> VPL of thalamus –> primary and secondary somatosensory cortices
Anterolateral System Vs Dorsal column-medial lemniscus
Dorsal column-medial lemniscus: no axons cross the midline until after they synapse in the medulla
Axons of the second-order neurons in the brainstem nuclei cross midline
Body somatosenosry system
Anterolateral: axons cross the midline when they are leaving the spinal cord
Axons of the second-order neurons in the spinal cord cross midline
For pain
second pain pathway - first targets
Reticular formation, Periaqueductal gray, Superior Colliculus: Parabrachial nucleus (in the pons), Medial thalamic nuclei
what are the types of pain info?
- mechanical: strong pressure
- thermal: extreme temperature
- chemical: histamines (itch) and other chemicals
- polymodal
how do opioids work
• Opioid receptors on terminals of primary afferent Bind to presynaptic terminal to inhibit glutamate/Substance P release
neurotransmitter for primary afferents (for pain)
• All primary afferents use glutamate as transmitter
second order projection neurons in _____ of the laminae cross the midline and then ascend towards the brainstem and thalamus
Axons from the second order projection neurons in I and V CROSS THE MIDLINE and then ascend towards the brainstem and thalamus