Pain experience Flashcards
where would you find high numbers of nociceptors?
cornea and tooth pulp
where would you find low numbers of nociceptors?
brain, liver lungs
what are free nerve endings in tissues, attached to nerve fibres?
nociceptors
what nerve fibres are nociceptors attached to?
c fibres
ADelta
what type of pain do C fibres result in?
slow, burning pain
what type of pain do Adelta fibres result in?
sharp, pricking pain
what is the resting membrane potential?
-70mV
What must the membrane potential reach to stimulate an action potential (THRESHOLD)?
-50mV
how do inflammed tissues cause a potential change?
they release chemicals and bind to protein channels
what do protein channels change shape in response to?
different temperatures
what protein activates a response at high temperature and spicy foods?
capsaicin
what does capsaicin activate?
TRPV1 receptor in C fibre terminals
what temperature does capsaicin activate at?
43 degrees
what temperature activates TRPV2 receptor?
52 degrees
what are histamine, serotonin, and bradykinin examples of?
algogenic substances
what do algogenic substances do?
activate/ sensitise nociceptive nerve endings
what happens to the AP in antidromic conditions?
it goes back up the nerve branch due to inactivated Na channels at the nerve junction
what causes the release of substance P at nerve endings?
axon reflexes
What presents in fine peripheral fibres and causes vasodilation, increase in vascular permeability and mast cell degranulation?
substance P
what does substance P release that causes more sensitisation?
histamine
what is the exaggerated response to a noxious/ nociceptive stimulus?
hyperalgesia
what is it called having pain from something that would not normally produce pain?
allodynia
what fibres does dental pulp contain?
Adelta
Abeta
C fibres
what are the 4 layers of pulp?
pulp core
cell rich zone
cell free zone
odontoblast layer
