Term
| What is the vestibular system comprised of? |
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Definition
| The vestibule and semicircular canals. |
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Term
| Which nerve are the vestibular and auditory nerves part of? |
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Definition
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Term
| What are the otolith organs and which part of the system are they part of? |
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Definition
| Utricle and saccule. The vestibule. |
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Term
| What are the roles of the utricle and saccule? |
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Definition
1) Detect changes in head angle
2) Detect changes in linear acceleration. |
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Term
| How are the maculae positioned in the saccule and utricle? |
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Definition
Sacule: vertical
Utricle: horizontal |
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Term
| Where do the kinocilia point in the maculae? |
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Definition
Sacule: away from the reversal line
Utricle: towards the reversal line |
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Term
| What is the role of the semicircular canals? |
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Definition
| They detect rotaional acceleration. |
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Term
| How many semicircular canals are there? |
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Definition
| 3. A superior, posterior and lateral. |
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Term
| Where are the hair cells in the semicircular canals? |
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Definition
| Embedded in the gelatinoous cupola in the ampulla. |
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Term
| What is special about the vestibular axons to the semicircular canals? |
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Definition
| They are spontaeneously active and can signal both excitation and inhibition. |
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Term
| Describe the nerve pathway from the otolith organs. |
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Definition
| Otolith organs- Lateral vestibular nucleus (via CN VIII)- Projections via vestibulospinal tract to control legs and maintain posture and to the cerebellum. |
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Term
| Describe the nerve pathway from the semicircular canals. |
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Definition
| Semicircular canals- Medial vestibular nucleus- Motor neurons of head and neck & extraocular motor neurons (CNs III, IV and VI) & via thalamus to cortex. |
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Term
| What causes motion sickness? |
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Definition
| Vestibular system and vision give conflicting signals. |
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Term
| What does the vestibulo-ocular reflex do? |
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Definition
| Stabilises eyes to keep them pointing in the same direction despite head movements (doesn't require vision). |
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Term
| What is the function of the endolymphatic duct and what can its blackage cause? |
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Definition
| It connects the membraneous labyrinth with the endolymphatic space and allows endolymph to be absorbed into the CSF to regulate pressure. Meniere's disease. |
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Term
| What are some of the symptoms of Meniere's disease? |
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Definition
1) Intermittent rotatory vertigo (sensation of spinning)
2) Nausea, sweating or vomiting. |
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