Week 3B - vestibular pt 1 - thurs Jan 23 Flashcards
the GTO location is the ___
tendon
GTOS detect ____ and are innervated by ___
their 2 functions are
active tension
Ib afferents
protective mechnism
modulate force
Go draw a muscle spindle
describe hte mechanism/pathway that the spindle activates the motor neuron (Eg reflex)
the mechanism that activates the MN directly is the monosynaptic reflex
when the spundle spindle lengthens and is stretched Ia (primaries) (which are sentistive to stretch) activate teh MN and create the reflex
why might it be beneficial for a sensory receptor liek a msucle spindle to have a special motor system to accomplish a refelx?
the msucle spindle is controlle dby the gamma system - this prevents the spindle from unlaoding during voluntary contractions and allows it to remain sensitve to stretch
he stretch reflex is called the monosynaptic reflex because
the Ia afferent synapses onto the Ia interneuron prior to
synapsing onto the alpha motor neuron (True/False).
A) True B) False
False - monosyanptic is one synaose directly on MN
are tehre receptors in the cartiliginous surfaces?
NO and not in sy=
are teh receptors in synovial membranes/
no
Join receptors respond to ___ of join movement and joint ____
limits of joint movement (extremes) and joint pressure (like swelling)
joint receptors code____ meaning they respond to both __ and ___
ambigously for joint movements - respond to both flexion and extension
IN terms of reflex activity joint receptors cause what effect on alpha MN and what does this suggest?
joint receptors cause a weak and infrequent effect on alpha MN
knee ligaments need to be rly stretched heavily to detect any EMG/AP activity - suffest protecive role for muscle regflexes
what are teh 2 general types of sensory receptors (vestibular end organs) and tehir subcategories
Semicircular canals
- horizontal, ant, post.
Otolith organs
- saccule
- Utricle
what do sesnosry recpetos care abotu int erms of the vesitbular system?
hwo the head is moving thru space
what are the vesitbualr mechanoreceptors and what do they do?
The hair cells ,kinocillium and stereocillium transform Mechanical energy in to neural energy
the hair cells (mechanoreceptors) in the vestibular system transform ___ energy into ___
mechanical into neural
what is the apex of the hair cell called/
kinocillium
what is the stair liek structure of hari cells called?
sterocilium
what happens when the sterocilia are pushed TOWARDS kinocilium
the hair cell depolarizes and increases teh firing rate
what happens when sterocilia are pushed AWAY from kinocilium?
hair cell hyperpolarizes and decreases the firing rate
what happens ar rest to hair cells?
vestibular affernts inn hari cells continue to fire at a baseline firing rate due to leaky ion channels
what type of motion semicircular canals detect?
angular acceleration
wher is the endolymph foiund int he SSC?
int he canal
wher are teh hair cells found in the SSC?
Cupula - hosue hari cells in the crista
what happens to semicircular canal
a) at rest
b) accelerating
c) decelartion
d) at a constant velcotuy>
at rest - backgorund firing rates
accelerating - depolrization and incrased firing rate
deccelrating = hyperpolarization + decreased firing rates
constant velocity - returns to normal lakiness and baseline firing rates
the _____ nerrve affernts are impacted in teh semicricualr canal during angular accelrations
8th
shaking head no occurs in the ____ canal
horizontal
nodding ehad yess occurs in the ____ cana;
anterior
putting ur head to ur shoudler (side to side) occurs in the ____ canal
psoterior
what leads to sensation of head rotaion?
the balance betwene elft and right excitation an dinhibition in semicircular canals
True or flase head rotation causes the same endolymph fluid movement on both sides of teh head
false - causes opposite
True or false - in both the right and left SSC dthe sterocilia are push towards the kiniocilum causing excitation/ incr firing rates/depolariation
FALSE - if stereociliar push toward kinocilium on right teh left will push them away causing inhibition
oppostie on each side of head
what is one of the main differnces between teh SSC and the otolith organs
Semicirc have endolymph = fluid and otolith has gel like substance (otolithic membrane)
what do otolith organs detec?
linear acceleration + acceleration from gravity
otoliths are smal ____ crystal embeded in ___
small calium carbonate crystals emebdded in gel like (gelatinous) material
the utricle detects _____
and saccule detect ____
these are both typs of ??
utricle detects horizontal linear accerelation
saccule detect vertical linear accelration
both types of otolith rpgans
for the otolith hair cells have ___ whcih __
cilia which rpojfect up into overlaying mebranf (otolithic mebrane) where small crystals are embedded
what happens when head tilts or accelrates to teh otolith organs?
rgavity causes otoliths to sldie pulling sterocilia and casuing hair cell to depolarize
what causes sitmualtion of otolith organs?
gravity or linear shear - linear accelration sesnitive
