Trigeminal Proprioception Flashcards
what is proprioception
awareness of position of body parts in relation to each other and surroundings
what is kinaesthesia
movement awareness
what are the receptors involved in proprioception
muscle spindles
golgi tendon organs
joint receptors
- also stretch receptors in skin
what does principal jaw closing muscles have
muscle spindles
do jaw open muscles have muscle spindles
no
what is designed to put force through teeth
jaw closing muscles
PDL mechanoreceptors
what is special about the TMJ
has range of receptors give information how open and how close and speed doing so of the jaw
what do inner ear receptors contribute
perceive head position
what are the two types of muscle fibres
extrafusla and intrafusal
what are extrafusal fibres
bulk of muscle fibres
contractile
generate force and movement
what are intrafusal fibres
muscle spindles
specialised muscle fibres
within a ct capsule
what are the there zones of an intrafusla fibre
2 contractile end portions
non contractile central portion can be stretched
what are the afferents of the intrafusal fibre activated by
stretch
what are the secondary nerve endings in the intrafusal fibre
detects length of fibres slowly adapting
what is the primary annulo-spira nerve endings
detects length of fibres and speed of change of length
what is the efferent in intrafusal fibres
gamma motor neurone
ake contraction
what fibres supply the extrafusal fibres
alpha motor neurones
what is significant about alpha motor neurones
fastest afferents in the body
how can you record muscle spindle activity
oscilloscope
what is seen by a muscle fibre at rest
spindle afferent at rest see AP’s fire at set rate
what happens to muscle fibres firing when stretched
the more stretched the more firing
what are the main roles of muscle spindle fibres
info about muscle length
act to maintain muscle length
what is the thought process behind jerk reflexes
muscle spindle afferents synapse with alpha motorneuorens increase stretch muscle increases firing which causes contraction
feedback loops synchronised muscle stretch
what is an example of muscle spindles in action
bucket fills with water
biceps spindles stretch
increased moo neurone drive to biceps
muscle length maintained
where are masticatory muscle spindles
in cell bodies in trigeiminla mesencehlaic nucleus in CNS don’t synapse here
where do muscle spindle afferents synapse for masticatory muscles
v motor nucleus
and cerebellum and cerebral cortex
what happens when muscle shortens
when shortens signal t alpha send a gamma also cause intrafusal to contract to keep it tense and therefore responsive
what do gamma motor neurones do
contraction of intrafusal fibres
maintain tension in spinde
maintain spindle afferent activity
alpha-gamma co activation
what is another muscle spindle role and what is analogy
load compensation
– carrot analogy
what are golgi tendon organs
series with muscle fibres in tendons
non in mast muscles
tension receptors
role in inhibit reflex
what are the joint receptors
pacinian - ligaments - acceleration
golgi - ligament - position
ruffini - capsule - movement
what is interdental detection
can detect 50 microns between teeth
what are the receptors for interdental detection
PDLM’s
muscle spindles
maybe joint receptors
what si the jaw repining test
ability to reposition jaw
accuracy of order <2mm
what are the receptors for jaw repositioning test
muscle spindles
TMJ
not PDLM’s as no tooth contact
