Vestibular system Flashcards
the semicircular canals respond to what?
head turning (angular acceleration)
what are the otolith organs?
utricle and saccule
what do the otolith organs respond to?
head position and linear acceleration
names of the 3 semicircular canals?
superior, lateral/horizontal, posterior
what detects movement in the semicircular canals?
ampulla- a swelling at one end of each canal
What is inside the ampulla?
a gelatinous mass called the cupula which sits atop the crista ampullaris
what protrudes from the top of crista ampullaris?
hair cells with kinocilium and sterocilia
what allows our semicircular canals to better calculate angular acceleration?
the difference between depolarization and hyper polarization on the different sides
How does the ampulla signal the vestibular neurons?
we turn our head, which moves the cupula and bends the hair cells which causes a change in membrane potential which then sends a signal to the vestibular neuron.
in the left horizontal semicircular canal, head rotation to the right leads to what type of polarization?
hyperpolarization
in the right horizontal canal, head rotation to the right leads to what type of polarization?
depolarization
what sits on top of the hair cells in the otolith organs? what does it contain?
otolithic membrane- contains crystals of calcium carbonate called otoconia
what do the utricle and saccules use to calculate linear acceleration and head position?
the differences in signal between utricle and saccule on the same side, and their partners on the contralateral side
basically- they are using both sides to understand what is happening
damage to the vestibular system can be caused by (5)?
inner ear infection, toxic reaction antibiotics, traumatic head injury, stroke (vestibular nuclei in brainstem), Meniere’s disease (excess endolymph)
Damage to the vestibular system can lead to (4)
Balance deficits-vertigo spontaneous nystagmus (pathalogical) involuntary rhythmic movements of one or both eyes at rest >> impaired gaze stabilization
