Mechanoreception No.1 Flashcards
what is mechanorception
detection of mechanical stimuli
with mechanoreceptors
what is adequate stimulus
pressure
vibration
tension
what is touch
sensory experience when mechanoreceptors are excited
involves CNS
what is exteroceptive
give information about things coming into contact with the body
what is proprioception
awareness of position
what is exteroceptors
muscosala nd skin receps
- mehanoreceps
- nociceptors
- thermoreceps
- chemoreceps
PDL Mechanoreceps
what are proprioceptors
PDL mechanoreceps muscle spindles joint recess golgi tendon organs inner ear
what do the mechanorecps of mucosa do
food texture- swallow food suitable
imp for mastication
what is function of PDL ligament mechanoreceps
forces of teeth
what are the mechanoreps in muscle
muscle spindles - monitor muscle length
what are mechanoreceps in joint recess useful for
joint position and movement
what sit he effect of stimulation of mechanorecps
sensation of touch
reflexes - jaw jerk, salivary reflexes
interact other sensory modalities - rubbing
what is the theory of vibraject
vibrating to activate the mechanorecps with vibration at same place of place activating nociceptors therefore trying to gate close and inhibit 3pain path
types of mechanoreceptorrs
physioloial classification
- aaptative properties -receptive field size
anatomical classification
what is rapidly adopting
AP force fires and then stops and adapts to force and maybe fires again when force goes off respond to changing states
what si slow adapting
apply same force and some receptors fire ad detect AP’s thro whole duration doesn’t adapt or very slow adapts
what are the four types of mechanoreceps
RA I
RA II
SA I
SA II
what is a receptive field
the area where a stimulus will affect the receptor covered by one receptor
what are the properties of RA I
small receptive field and rapid adaptation
what are the properties of RA II
large receptive field and rapid adaptation
what are the properties of SA I
small receptive field and slow adaptation
what are the properties of SA II
large receptive field and slow adaptation
what are some mechanoreceptors
meissners corpuscle
pacianian corpuscle
merkel cells
Ruffini ending
what are some RA I receptors
preset in
- oral mucosa
- vermillion border
- mucosa of lip
- hard palate
what are some RA II receptors
pacinian corpuscles
depp in mucosa
rare in oral mucosa
what are some SA I receptors
present in
- tongue
- lips
- cheeks
what ar some SA II Receptors
ruffini endings
PDL
what is transduction
mechanical to electrical energy
causes deep to AP
what is a parent axon
type nerve carry info
A- beta large myelinated fibres- fast
what are touch thresholds
lips and oral mucosa - 10 mg
teeth 0.01N
sense of being touched
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