Term
Where is the vestibular system found? |
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Definition
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The vestibular organs (the part of the ear that senses motion) send their signals through the vestibular part of which cranial nerve? |
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Definition
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Term
Which structures work on the right and left side to detect rotations of the head in all 3 directions (ANGULAR ACCELERATIONS)? |
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Definition
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Term
How many semicircular canals are there? |
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Definition
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Term
Which structures sense LINEAR ACCELERATIONS (such ads gravity)? |
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Definition
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Term
What two structures make up the otolith? |
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Definition
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Term
The (otoliths/semicircular canals) can tell you when your body is tilted one direction or another. |
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Term
moving your chin up and down (in a "yes" nodding motion) is called what? |
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Definition
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moving the ear towards the shoulder is called a what? |
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Definition
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Term
the movement of shaking your head (as if saying "no") is called what? |
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Definition
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Term
what is the reflex in which eye velocity compensates for head velocity? (Keeping visual field stable even when you are shaking your head very quickly) |
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Definition
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Term
what is the reflex which allows head position to be maintained despite body movements? |
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Definition
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Term
what is a reflex that involves postural changes in response to a vestibular signal? |
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Definition
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Term
under normal circumstances, hair cells are somewhat (polarized/depolarized) and are firing a resting action potential rate |
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Definition
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Term
Deflection of the stereocilia toward the kinocilium causes _____ channels in the apical portions of the stereocilia and kinocilium to open. |
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Definition
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Term
K+ flows into the stereo/kinocilia from the endolymph, depolarizing the cell membrane. This depolarization in turn causes ________ channels at the base of the hair cells to open, allowing _______ to enter the cell |
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Definition
voltage-gated Calcium channels
Calcium |
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Term
____ influx into the stereo/kinocilia causes synaptic vesicles to release neurotransmitter into synaptic clefts |
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Definition
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Term
which neurotransmitter is most commonly released from hair cell cilia? |
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Definition
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Term
increased release in glutamate causes depolarization of the membrane in the post-synaptic cell, which increases the firing rate of the vestibular (efferent/afferent) fibers |
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Definition
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Term
sterocilia moving towards kinocilia (increases/decreases) the firing rate of the afferent fibers |
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Definition
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Term
stereocilia moving away from the kinocilia causes (increase/reduction) of calcium influx, a net (increase/reduction) in neurotransmitter release, (hypo polarization/hyperpolarization) of the post-synaptic membrane, and (increase/decrease) in the firing rate of vestibular afferent fibers |
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Definition
stereocilia moving away from the kinocilia causes REDUCTION of calcium influx, a net REDUCTION in neurotransmitter release, HYPERPOLARIZATION of the post-synaptic membrane, and a REDUCTION in the firing rate of vestibular afferent fibers |
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Term
the anterior portion of the sacculus has cells that are sensitive to movement in which directions? |
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Definition
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Term
which directions of movement does the utricle sense? |
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Definition
medial and lateral, posterior and anterior |
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Term
which directions of movement does the sacculus sense? |
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Definition
up and down MOSTLY, (also forwards and backwards?) |
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Term
moving your head to the right, the utricle of one ear will move/sense _____ and the utricle of the other ear will move/sense ______ |
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Definition
one will move/sense medial, one will move/sense lateral |
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Term
what are the "little rocks" in the ear that increase the effective force on the stereocilia (they sit in a gelatinous matrix where stereocilia insert) |
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Definition
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Term
the swelling at the base of each semicircular canal is called what? |
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Definition
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Term
the structure in the ampulla that is analogous to a sail that acts to intercept fluid motion is called what? |
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Definition
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Term
what type of acceleration is the cupula sensitive to? |
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Definition
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Term
an angular acceleration causes fluid in the semicircular canals to move in the (same/opposite) direction, which displaces the cupula |
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Definition
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Term
what are the 3 different semicircular canals? |
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Definition
horizontal canal anterior canal posterior canal |
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Term
if you move your head horizontally to the right while the head is tilted down 30 degrees, which canals will increase firing rate and which canals will decrease firing rate? |
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Definition
moving horizontally to the right, the right horizontal canal will increase firing rate, and the left horizontal canal will decrease firing rate |
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Term
the right anterior canal is paired with which canal on the left side? |
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Definition
the left posterior canal (RALP and LARP) - R anterior/L posterior, L anterior/R posterior |
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Term
What head motion excites only the horizontal canals? |
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Definition
tilting the head down 30 degrees and rotating the head |
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Term
Where do the two descending vestibular spinal tracts descend from? |
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Definition
one descends from the LATERAL VESTIBULAR NUCLEUS one descends from the MEDIAL VESTIBULAR NUCLEUS |
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Term
the (lateral vestibular nucleus/medial vestibular nucleus) is more involved in postural musculature |
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Definition
lateral vestibular nucleus |
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Term
which tract (lateral vestibulospinal tract/medial vestibulospinal tract) is more appropriate for innervation of the trunk muscles? |
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Definition
medial vestibulopinal tract |
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Term
which tract is involved in not letting you fall over when you have your eyes closed? |
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Definition
lateral vestibulospinal tract |
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Term
which tract has a huge influence on anti-gravity muscles? |
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Definition
lateral vestibulospinal tract |
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Term
The lateral vestibulospinal tract runs into the (dorsal/ventral/lateral) horn which is appropriate for innervating which muscles? |
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Definition
ventral horn
distal leg muscles |
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Term
In addition to the descending vestibular tracts there are also projections from the vestibular nuclei to the thalamus, from which information is relayed to which two places int the cortex? |
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Definition
parietal and somatosensory areas of the cortex |
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Term
vestibular signals sent to the cortex via the thalamus can allow you to do what? |
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Definition
move around with your eyes closed or in a dark room |
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Term
CN 6 (abducens) innervates which muscle in the vestibulo-ocular reflex? |
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Definition
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Term
About 40% of the cells in the abducens nucleus are internuclear neurons that project to the (ipsilateral/contralateral) oculomotor nucleus |
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Definition
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Term
Turning your head with your finger held in front of you, the finger seems to stay still due to which reflex? |
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Definition
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Term
In the vestibule-ocular reflex, turning your head to the left will cause afferents on the (right/left) to increase firing and turn eyes to the right |
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Definition
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Term
T or F Vestibular responses are good at signaling slow changes |
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Definition
False
Analogy is with slow movement of a glass of water, the water does not move much |
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Term
what movements does the utricle sense? |
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Definition
movements in the the horizontal plane (forwards, backwards, left, right) |
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