Quiz #1: Pain (6) Flashcards
What is nociception?
physiological process involved in the transduction of a noxious stimulus (one strong enough to signify tissue damage) and the conduction of impulses from the periphery to the cortex
What is pain?
Unpleasant sensory/emotional experience associated with actual/potential tissue damage
Pain vs nociception?
Nociception = neural process of encoding harmful stimuli
Pain = the subjective experience of that encoding (perception
What are nociceptors?
sensory receptors involved in pain
subset of peripheral sensory organs that respond to noxious stimuli
What are the categories of pain?
- physiological pain
- clinical (inflammatory) pain
- persistent (neuropathic) pain
What is the four parts of the nociceptor process?
- transduction
- conduction
- spinal processing
- perception
What is clinical (inflammatory) pain?
not as easily localized as physiological pain
awareness of injured area (healing and protected from reinjury)
guarding behaviors
Why is physiological pain?
sharp + easily localized
site of injury is known
“Fast pain” / “slow pain”
What is persistent (neuropathic) pain?
maladaptive (not providing adequate or appropriate adjustment to the environment or situation)
leads to behaviors that diminish quality of life
difficult to localize
What are the two types of physiological pain?
- fast pain - sharp/well-localized
- slow pain - aching or throbbing/poorly localized
How are nociceptors activated?
transduction of tissue damage into an action potential
peripheral nociceptive nerve terminal
Ca2+ channels
What is the main difference between the two types of physiological pain?
carried by different nerve fibers
fast pain - Aδ fibers (myelinated)
slow pain - C fibers (unmyelinated)
What are the types of Ca2+ channels involved in the transduction of noxious stimuli?
- Vanilloid receptor (VR1) - transduction of noxious heat
(aka capsaicin receptors or transient receptor potential vanilloid TRPV1) - Purinergic receptor (P2X2) - senses a localized increase in ATP (Bc cell contains a lot of ATP, if dies, releases it, ATP binds to purinergic receptors, produces glutamate)
What are Na+ channels in nociceptor activation?
Acid sensing ion channel (ASIC)
sensitive to the increase in H+ (aka decrease in pH)
What does the influx of calcium do the the cell?
depolarize it
release NT: glutamate
go to Aδ fibers or C fibers to show there is injury
TRUE OR FALSE
Regardless of how or which calcium channels are activated, glutamate will always be released.
TRUE
What does the influx of Na+ ions do to the cell?
depolarize it
release NT: glutamate
go to Aδ fibers or C fibers to show there is injury
What is bradykinin?
activates signaling pathways inside the cell
activates 2:
- PKC (protein kinase C)
- PKA (protein kinase A)
What do PKA and PKC do?
increase intracellular Ca2+
–> will lead to eventual released of calcium ions
What does changes/mechanical deformation of the plasma membrane do?
mechanical receptors
any time there is change in plasma membrane, will cause the release of glutamate as well
What are nociceptors found in teeth?
- Aδ fibers (thermoreceptors/mechanoreceptors)
- C fibers (polumodal chemoreceptors like H+/ATP/Bradykinin/others)
Why does the tooth hurt with heat/cold?
Activated TRPV1 –> release calcium ions –> release of glutamate –> PAIN
What is the hydrodynamic mechanism?
Thought of why mechanical changes causes pain in the tooth
odontoblasts sit in fluid-filled tubules
if those fluids move inside those tubules, odontoblasts respond, then PAIN
mechanoreceptors (changes in cell membrane due to movement of fluid)
What happens at the spinal cord?
NT is glutamate
signal from Aδ fibers/C fibers: synapse at projection neuron
release glutamate
glutamate activates AMPA receptors