travers 4 peripheral pain Flashcards
acute pain
short term, identifiable source (hot stove)
chronic pain
long term, frequently non-identified source
normal pain
A delta and C fibers
pathological pain
hyperalgesia, peripheral and central sensitization
A delta represents what % o f cutaneous nociceptors? size and myelination? velocity? neuropeptides? Na channels? TRP expression? 1st or second pain etc?
13%, small and lightly militated, fast 12-36 m/s, yes to NP’s, mainly TTX-sensitive Na channels, TRPV2 more likely, mainly noxious mechanical stimuli (some heat), 1st pain, sharp, fast, well localized.
C fibers represents what % o f cutaneous nociceptors? size and myelination? velocity? neuropeptides? Na channels? TRP expression? 1st or second pain etc?
87%, very tiny and no myleination, slow .5-1.2 m/s, both TTX-sensitive and TTX-r Na channels, TRPV1, 2nd pain, slow, dull or burning, poorly localized. POLYMODAL response (pinch and thermal or chemical)
TRP receptors
large family of receptors transducing chemical and thermal nociception
TRP receptors found on trigeminal sensory fibers respond to chemicals to mediate _______
chemesthesis
epithelial sodium channels may play role in what
mechanical nociception
chemesthesis, fibers? and what sensation is experienced
common chemical sense, C fibers mainly, some A have it. burning or tingling sensation, salt water on open wound, chili peppers in food (capsacicin)
TRPV1 is called what
Vanilloid Receptor
TRPV1 responds to what and what does stimulation result in
responds to 1. capsaicin 2. heat 3. protons (from inflamed tissue= acidic, H’s) POLYMODAL
branches of trigeminal nerve with prominent chemesthesis
in the nasal, ehmoid from V1, in the oral cavity, posterior palatine and nasopalatine nerve from V2 and lingual nerve from V3
which is faster in trigeminal sensitivity, chemical or mechanical stimuli?
mechanical .5 sec. (intense touch) chemical liked capsaicin is 1 sec
true/false, when a neuron responds to a stimulus it always reaches conscious perception
false, it doesn’t always
chemesthesis have high or low chemosensitivity?
high
what sensations does chemesthesis activate?
mostly burning and tingling
what are “removal” reflexes?
salivation, coughing, tearing, sneezing.
dentin tubules have what kind of fibers?
A delta fibers-
- fibers extend part way into tubules,
- mechanical, thermal, and chemosensitivity,
- sharp pain,
- contain calcitonin gene related peptide (CGRP)
pulp chamber has what kind of fibers?
C fibers
- contain substance P
- thermal sensitivity
- chemosensitivity to inflammatory mediators
- dull throbbing pain.
which mechanical force do A delta fibers respond to most
Air blast > dental bur > scrapping > osmotic stimulus
C fibers in tooth pulp respond to mainly what and produce what kind of pain
respond to inflammatory mediators: produce dull/ throbbing pain.
what theory is the transduction of sharp pain?
hydrodynamic theory.
how does the smear layer relate to pain transduction?
high pressure applied to dentinal tubules does not cause pain UNLESS EDTA dissolves smear layer.
