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28 Cards in this Set
- Front
- Back
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List the 2 otolith organs. What is their function?
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1. Utricle
2. Saccule *Detect head tilt and linear acceleration |
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What sort of motion do the semicircular canals detect?
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Angular acceleration
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All chambers of the vestibular labyrinth are filled with what fluid?
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Endolymph
*All chambers are continuous with one another and with the scala media of the cochlear duct |
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Which cells make up the sensory component of the vestibular labyrinth?
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Hair cells
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The cilia of the hair cells contain one long cilium with a bulbous end that is called ________ with multiple _________.
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Kinocilium & steriocilia
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All cilia project into a gelatinous substance called..?
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Otolithic membrane
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What are otoliths, and where are they located?
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Crystals of calcium carbonate
*Embedded in the otolithic membrane |
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If the sterocilia bend towards the kinocilium, are the hair cells depolarized or hyperpolarized?
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Depolarized
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Accelerating in a car and moving up and down in an elevator are detected by which structures?
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Otolith organs
(utricle and saccule) |
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What is the name of the sensory epithelium in the otolith organs?
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Macula
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Describe the orientation of the macula in both otolith organs and how this contributes to their function?
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Utricle --> macula is in the HORIZONTAL plane --> responds to horizontal movements
Saccule--> macula is in VERTICLE plane --> responds to vertical movements |
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What is the name of the line demarcating the polarization of the hair cells in the macula?
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Striola
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Which fluid is found within the semicircular canals?
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Endolymph
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Each of the semicircular canals has a bulge that is called..?
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Ampulla
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What is the name of the sheet of cells in the semicircular canals that contain hair cells
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Crista
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The cilia in the semicircular canals project into a gelatinous mass called ..?
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Cupula
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Do the semicircular canals detect gravity?
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No
*The densities of the endolymph and cupula are the same |
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Describe the direction of the force exerted by endolymph in the semicircular canals during head rotation
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The endolymph exerts a force in the OPPOSITE direction of head rotation
*This is because the endolymph has inertia. When the head rotates one direction, the endolymph lags behind. |
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Describe how the semicircular canals are paired with respect to each side of the body
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Paired canals:
R & L horizontal canals R anterior & L posterior canals L anterior & R posterior canals |
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Where are the cell bodies of the bipolar vestibular afferents located?
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Vestibular (Scarpa's) ganglion
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Pathways from the vestibular nuclei connect to which 3 cranial nerves?
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CN III, IV, VI
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Vestibular pathways descend to spinal motor neurons via which pathways?
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Medial and lateral vestibulospinal and reticulospinal pathways
*Project to the cerebellum |
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Some neurons from the vestibular nuclei ascend to which nuclei before projecting to the parietal (somatosensory) cortex?
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1. Ventral posterior nucleus
2. Posterior nuclear group |
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Which portions of the cortex provide the conscious perception of vestibular stimuli, and are involved in detecting body position relative to the environment?
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1. Somatosensory cortex
2. Portion of the parietal cortex near the insula. |
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What is the vestibuloocular reflex?
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Maintains a visual image on the retina during head turning
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What is the vestibulo-cervical reflex?
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Causes head movements in response to vestibular signals
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If you fall forward, which reflex extends the arms to lessen the impact of the fall?
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Vestibulo-spinal reflex
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Damage to which semicircular canal will cause the eyes to move slowly to the right with fast movements to the left?
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Right semicircular canal damage
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