Term
| Where is the vestibular apparatus located? |
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Definition
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Term
| As the cochlear duct, the vestibular labyrinth is filled with _____ |
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Definition
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Term
| 3 things that make up the vestibular labyrinth |
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Definition
1. 3 semicircular ducts
2. saccule (a small expansion)
3. utricle (a small expansion) |
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Term
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Definition
| structures equipped with hair cells that are found in expansions of the ducts & respond to movements of the endolymph |
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Term
| Movements of the endolymph arise when the head rotates, & the hair cells thus signal _____ |
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Definition
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Term
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Definition
| flat surfaces (saccular & utricular) on which the hair cells in the saccule & utricle are found |
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Term
| The stereocilia of the hair cells are embedded in a gelatinous substance containing _____ |
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Definition
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Term
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Definition
| where afferents from the vestibular apparatus end; located in the upper medulla & lower pons |
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Term
| 3 main directions from the vestibular nuclei in which signals flow |
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Definition
1. to the spinal cord
2. to neuronal groups controlling eye movements
3. to the cerebellum |
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Term
| 2 main reflexes controlled by connections from the vestibular nuclei |
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Definition
1. postural reflexes (maintaining the upright position)
2. vestibulo-ocular reflexes (fixation of visual targets) |
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Term
| Signals from _____ receptors contribute to our conscious awareness of the position of the body in space |
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Definition
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Term
| 2 sensations that can be caused by dysfunction of the vestibular apparatus |
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Definition
1. dizziness
2. dis-equilibrium |
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Term
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Definition
| contains vestibular receptors & is embedded in the temporal bone & surrounded by a space containing perilymph; similar to the cochlear duct with the organ of Corti |
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Term
| What fills the membranous labyrinth? |
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Definition
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Term
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Definition
| swelling in the end of the semicircular ducts close to the utriculus |
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Term
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Definition
| a jellylike mass into which the cilia project |
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Term
| What does it mean that a pair of ducts gives "complementary signals" to a given rotation? |
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Definition
| increased signal frequency from the one & reduced from the other |
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Term
| The utricle records especially _____, whereas the saccule probably records mainly _____ of the head |
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Definition
| lateral tilt; flexion-extension |
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Term
| What does it mean that the vestibular apparatus has "static sensitivity"? |
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Definition
| it has the ability to provide information about the position of the head at any one time |
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Term
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Definition
| the utricle & the saccule of the vestibular apparatus; called this because they deal with the property of static sensitivity |
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Term
| When is the dynamic sensitivity of the utricle & the saccule seen? |
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Definition
| during linear acceleration |
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Term
| Does the vestibular system have a high or low degree of multisensory integration? |
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Definition
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Term
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Definition
| the collection of large & small vestibular nuclei |
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Term
| 2 branches of the primary afferent vestibular fibers when entering the brain stem |
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Definition
1. ascending branch
2. descending branch |
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Term
| 2 termination fibers that overlap in the vestibular nuclei but show notable differences in distribution |
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Definition
1. ampullar cristae
2. musculae |
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Term
| 3 parts of the CNS where the vestibular complex receives afferents from |
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Definition
1. spinal cord
2. reticular formation
3. cerebellum |
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Term
| Do the vestibular nuclei receive signals from the cerebral cortex? |
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Definition
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Term
2 parts of the cortex where the corticovestibular fibers arise
(hint: they receive converging information from the labyrinth & proprioceptors) |
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Definition
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Term
| How are the vestibular nuclei influenced from the posterior parietal cortex? |
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Definition
| it is concerned with spatial orientation & goal-directed movements |
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Term
| Are vestibular reflexes (vestibulospinal ones in particular) modulated in conjunction with voluntary movements? |
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Definition
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Term
| 3 main regions where the vestibular nuclei act schematically |
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Definition
1. motoneurons in the spinal cord
2. motoneurons in the nuclei of the extraocular muscles
3. cerebellum |
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Term
| 2 kinds of reflexes that are elicited from the vestibular apparatus |
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Definition
1. vestibulo-ocular reflexes that control eye movements
2. labyrinthine reflexes mediated by the vestibulospinal tracts controlling bodily postures |
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Term
| What is the difference between tonic & phasic reflexes? |
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Definition
tonic: elicited by signals from the utricle & the saccule
phasic: caused by signals from the semicircular ducts when the stimulus is rotation of the head & from the utricle or saccule when the stimulus is linear acceleration |
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Term
| What does the vestibulo-ocular reflex do for the retina? |
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Definition
| keeps the image stationary when the head moves |
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Term
| What is a movement of the head in any direction accompanied by? |
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Definition
| a compensatory movement of the eyes in the opposite direction & with the same velocity of the head movement |
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Term
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Definition
| a fast movement of the eyes that occurs in the same direction as the head movement when the head movement becomes large so that it becomes impossible to keep the image stationary even with maximal excursion of the eyes |
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Term
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Definition
| the alternation between slow & fast/saccadic eye movements |
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Term
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Definition
| when the nystagmus was produced by stimulation of the semicircular ducts |
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Term
| What kind of nystagmus occurs when a train-passenger watches a landscape pass by? |
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Definition
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Term
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Definition
| a change of muscle tension (especially in the extremities supporting upright stance) induced by a change in the position of the head relative to the body |
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Term
| What tracts are involved in the mediation of the labyrinthine reflexes |
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Definition
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Term
| The reflex center of the neck reflexes is located in the _____, & the effects on the motoneurons are most likely mediated by both the reticulospinal & vestibulospinal tracts |
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Definition
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Term
| In infants, have comprehensive, high-level motor programs developed & accordingly, all postural reflexes operate normally? |
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Definition
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Term
| What does the area close to the PVIC in the posterior parietal cortex do? |
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Definition
| integrates vestibular & optokinetic information |
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Term
| Does vestibular activation occur in the premotor cortex? |
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Definition
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Term
| Is the fusiform body area particularly activated by recognition of whole human bodies or body parts? |
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Definition
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Term
| Does the extrastriatal body area in the occipital lobe respond especially to recognition of whole human bodies or body parts? |
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Definition
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Term
| 2 different aspects of internal bodily representation |
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Definition
1. body image
2. body scheme |
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Term
| Is the body scheme (provides a basis for our actions) continuously updated during movements? |
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Definition
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