3- LA in dent Flashcards
unpleasant sensation usually initiated by a noxious stimulus and over specialized neural network to the CNS
pain
biochemical mediators of pain
acetylcholine prostaglandin histamine serotonin kallikrinogen plasma factor glass factor
concentration gradient of resting state
-70 to 90mV
return to resting potential takes about ___
3 to 4 msec
period of time after an action potential has been fired during which another action potential cannot be fired no matter how strong the stimulus
absolute refractory period
when the ionic imba;ance begins to return to the polarized state
relative refractory period
period of time when a nerve can be stimulated to fire an action potential again but with a larger than threshould stimulus
relative refractory period
explain saltatory conduction
stimulation takes place only at the nodes of ranvier in myelinated fibers therefore it is a faster transmission of impulse because it will not travel the whole length of the fiber
all or none law of nerve conduction
whole nerve fiver is stimulated or not at all
dual nature of pain
pain perception -physio-anatomical process
pain reaction -psychophyshiologic process (manifestation of the pain)
theories on pain
- specificity theory
- pattern theory/summation theory
- gate control theory
person: specificity theory
descartes
explain specificity theory
specific nerve fibers for specific nerve sensations
free nerve endings for pain sensation
pacinian corpuscle for pressure
karuse and bulb for temp
person: pattern theory
Goldscheider
explain pattern theory
a combination of different sensations or intensity of different sensation can confuse the CNS and will interpret this as pain only
