week 3-2 Flashcards
what are the sensory receptors in the inner ear
- Semicircular canals
- Otoliths
what are hair cells
transform mechanical energy into neural activity
which one is the kinocilium
tallest strand on the hair cell
which one is the sterocilla
all of the smaller ones
what happen when the sterocilla are pushed toward the kinocilium
the hair cell depolarizes
what happens when kioncillium are pushed into the sterocilla
hyper polarizes
what do hair cells respond to
acceleration or gravity that is in line with the hair cell
parts of the semi cirular canal
canal and cupula
canal
filled with fluid (endolymoh)
cupula
houses hair cells in the Crista
what does the semi circular canal detect
angular acceleration
what does acceleration lead to
increased firing rate
what deceleration leads to
hyperpolarization
(decreased firing) in the 8th nerve afferents
what happens to firing rate during a constant velocity
the hair cells return to normal leakiness, and the 8th
nerve afferents return to baseline firing rates
at rest
- no angular acceleration
- no relative motion between canal and endolymph
- capula not detected
- no perceived angular movement
acceleration
-angular clockwise acceleration
-inertia cause endolymph to lag behind
- cupula deflected right
-perceived clockwise movement
constant angular motion
-endolymph moving at the same speed as the canal
-no relative motion
-cupla not deflected
- no angular motion
deceleration or stopping of motion
-canal stopped
-endolymph movement keeps it moving clockwise
-cupula deflected left perceived
-perceived counterclockwise movement
horizontal canal
rotation around the transerves plan
ex yaw NO
posterior canal
rotation around the x axis
ex roll shoulder to shoulder
anterior canal
pitch YES
around the y axis
semi circular canal balance
Balance between left and right excitation and
inhibition that leads to sensation of head
rotation
Head rotation causes opposite
endolymph fluid movement
This causes stereocilia to be pushed
towards kinocilium in the left semicircular
canal = excitation
what is the cupula surrounded by
endolymph fluid
Otolith organs
Otoliths or otoconia - small calcium carbonate
crystals embedded into gelatinous material
where are the small crystal embedded
in this membrane
Shearing of the membrane causes the cilia to move
when the head tilts or accelerates what deos gravity do
the otoliths to slide,
pulling the stereocilia and causing the hair cell to depolarize
gravity in the otolith organs
or linear shear
due to movement causes
stimulation
What are the otoliths sensitive to
linear acceleration
when we have a motion that is not in line with the sterocilla (perpendicular)
we don,t get any response (no change in any firing rate)
what does the firing rate return too
base line firing rate
balance on both sides of head
head rotation causes opposite endolymph fluid movement
what moves the hair cells
otolithic membrane (gel like substance)
utricle ___ linear acceleration
horizontal
saccule ___ linear acceleration
vertical
why does alcohol make you spin
alcohol blood thinner and decreases bone density
alcohol with the endolymph
the density between endolymph and cupula becomes imbalanced
less density on cupula, hair cells move artificially
BPPV typically occurs in older adults
typically occurs in older adults
cause:
idiopathic (hit to the head)
pathophysiology
otolith dislodged into semi circular canal especially when lying down
