Neurophys part 2 Flashcards
Type of stimulus that activates merkel and ruffini
Steady pressure
Type of stimulus that activates meissner and pacinian
vibration, which causes tingling sensation
location of meissner and merkel
epidermis
location of pacinian and ruffini
dermis
Sensitivity of meissner and merkel
sensitive- activate with smaller stimuli
Sensitivity of pacinian and ruffini
lower sensitivity, activate with more stimuli
precision of meissner and merkel
more precise, smaller receptive field
Precision of pacinian and ruffini
less precise, larger receptive field
Which receptors are tonic/phasic
Tonic: merkel and ruffini (continued sensation like pressure/vibration)
Phasic: meissner and pacinian(rapdily adapt- wearing clothes)
How does the brain know the difference between light and hard touch
AP frequency increases with harder and stronger touch
What are mechanical nocioceptors stimulated by
sharp and high pressure
What are chemical nocioceptors stimulated by
H+ ions, bradykinins
What are thermal nocioceptors stimulated by
cold: <20C
hot: >40C
What are fast pain nocioceptors stimulated by and what neurotransmitter is involved
a gamma fibers, glutamate
What are slow pain nocioceptors stimulated by and what neurotransmitter is involved
chronic pain- c fibers
glutamate and substance p
What is hyperalgesia
Increased pain from a normally painful stimuli (I.e. piniching is normally painful, but even more painful abnormally so)
What is allodynia
Pain from a sitmulus that doesnt usually cause pain (i.e. touching skin over broken bone- touching doesn’t usually cause pain, but does)
What cells do injured cells release
Prostaglandins, 5-HT, K, bradykinin, histamine
What is the pain-spasm cycle
first tissue damage leads to pain, pain leads to muscle spasm, spasm causes more pain, more pain causes more spasm