anatomy Flashcards
what do cilia in semicircular canals detect?
skull angular acceleration/deceleration
not constant velocity
Within the ampulla of each semicircular is the tallest cilia called?
Movement toward is +/-?
Movement away s +/-?
kinocilium
toward - excitatory
away - inhibitory
cochlea and vestibular organ make up?
labyrinth
what issues are related to the cochlea?
- Hearing loss
- Tinnitus
- Pressure in the ear
- otalgia – pain
- otorrhea - discharge
membranous semicircular canal size?
0.25mm in diameter, capillary in size, very tiny
describe how R Ant/ L Post semicircular canals are functional pairs?
If rotate head L by 45 deg, R Ant and L Post canals are in sagittal plane.
When head nods- one is excitatory and other is inhibitory
- anterior/posterior canal kinocilium away from utricle
- displacement is excitatory for ant/post canals; inhibitory for the horizontal canal
Utriculofugal cupular displacement
- horizontal canal kinocilium toward utricle
- excitatory for the horizontal canal; inhibitory for the anterior/ posterior canal
Utriculopetal cupular displacement
how does alcohol cause dizziness?
Cupula dome structure containing cilia when healthy has the specific gravity is same as surrounding endolymph;
alcohol is lighter than endolymph and diffuses into cupula; cupula is lighter and make head feel like rotating
what may disturb health of cupula?
trauma, intoxication, BPPV
what vestibular system part detects
- linear acceleration
- gravitational force
- head location in space- Head tilts and Translation of head in space
- part of postural control
Otolith organs (utricle and saccule)
Cilia is on floor of what otolith organ detect horizontal plane, eg. speeding in car
utricle
Cilia is on medial wall of what otolith organ
detect vertical plane, eg. going up elevator
saccule
- calcium carbonate rocks in otolith organs
that can get loose from their membrane - attached to cilia pulled on by gravity
Otoconia
problems with otoconia - feeling? acute disturbance
Pulsion, loss of balance, feel pushed/shoved in one direction
problems with otoconia - feeling? go into semicircular canals
vertigo, BPPV
when does otoconia break away more?
older age, female (especially if osteoporosis/osteopenia)
- located in endolymph of ampulla of semicircular canal and utricle
- help break down loose otoconia
- Responsible for calcium homeostasis and potassium transport
Dark cells
Decreased number of these in Meniere’s disease and labyrinthitis which may account for increased case of BPPV?
dark cells
how many vestibular organs do we have?
10
a. 3 semicircular canals
b. Utricle – horizontal plane
c. Saccule – vertical plane
when sleeping, what canals do otoconia typically travel into?
posterior and horizontal canals are dependent
recurring BPPV may be due to
- Increase loose otoconia
- Decrease in dark cells to help degrade otoconia
