Mechanoreception No.1 Flashcards Preview

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Flashcards in Mechanoreception No.1 Deck (43)
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what is 2 point discrimination tests

experiment ot see resolution touch diff parts of body
how close two blunts point can be to distinguish two points


what are the 2 point discrimination thresholds fro tip tongue and lips

low 2 point threshold
tip tongue 1mm
centre lip

high innervation density
small receptive field


what are the 2 point discrimination thresholds for fingertips

low 2 point thresholds
able to discriminate small objects


what are the PDLM's

periodontal ligament mechanorceep
imp sensory
exteroceptive role (tp tooth)
proprioceptive role (chewing not aware of forces)


what are the nerve endings of PDLM

ruffini nerve endings


what are the affreents for PDLM's

A beta axons
approx 300 per tooth


what are the cell bodies in PDLM's

V ganglion
mesencephalic nucleus - proprioception


what studies PDLM in animals

cat canine prep
localise indie receps
single fibre recordings


what studies PDLM in humans

recordings from IAN
discrete forces applied to teeth


what are PDLM properties

no branched axons between adjacent teeth PDLs easy to localise
innervation density higher at apex


what is the adequate stimulus for PDLM

tension in PDL due to pressure applied to tooth
tooth moves around in fulcrum


what does the amount of PDLM activity dept on

direction of applied force
magnitude force
adaptation props
threshold of receps
position of receps in PDL


why are there differences in PDLM's

linked to position relative to fulcrum

smaller stimulus nearer the fulcrum