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16 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What do the maculae detect? what do they not detect?
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linear acceleratin not lineary velocity
(static position of head related to gravity and to linear acceleration) |
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How are the hair cells laterally polarized?
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- kinocilium displaced to one side
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How are the hair cells vertically polarized?
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- the basal end is like any neuron
- apical end is mechanical transduction |
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What do the semicircular canals detect?
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angular acceleration
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When the head is turned towards the left what happens to the paired set of canals?
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The left canal depolarizes
The right canal hyperpolarizes via interneural connections |
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What does it mean that hair cells have resting depolarization?
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- the tip links of the stereocilia are not completely closed even at rest so that some ions are able to flow in and cause a low firing of the nerves at all time unless hyperpolarized
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Why does the cupula not respond to gravity?
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- specific gravity is 0 (no otoliths)
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How is the semicircular canals rapidly adapting?
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- rotate at first the endolymph is stationary but if continued eventually begins to flow as well so no longer detect movement b/c cupula is not displaced
- if suddenly stop moving the endolymph continues at first, cupula moves in the opposite direction so sense spinning opposite way |
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What is the purpose of the push pull method seen in the semicircular canal pairs?
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- fine tune to become more accurate
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What are two ways to decide where the damage is when a patient has vertigo?
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1. stumble to ipslateral side
2. fast phase of nystagmus to contralateral side |
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What are the 2 main mechanisms that stabilize the eyes?
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1. vestibular input
2. visual input |
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what are the main differences between visual and vestibular input?
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- visual has long latency, will not adapt (so always detect movement), sensitive to even low velocity, receive immediate feedback
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What are the 3 minor mechanisms that enable stabilization?
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1. neck proprioception
2. neck reflexes 3. sensory |
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What is ototoxicity?
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- drugs, CO2, heavy metal
- permanent deafness due to sensory neural loss (hair cells die) |
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What is endolymphatic hydrops?
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- abnormal endolymph
- endolymph is supposed to have high K and without the cells ar less susceptible to mechanical movement - afffects hearing, head rotation, adn balance - problem may be in the stria vascularis |
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What is Benign paroxysmal positional vertigo
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- otolith displaced from macula
- falls into semicircular canals which has hair cells that detect - patient feels dizzy |
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