Term
| Where evolutionary vertebrae middle ear ossicles originated from? |
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Definition
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Term
| Where vertebrae middle ear ossicles originated from during embriogenesis? |
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Definition
| Mesoderm cells and neural crest |
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Term
| When did tympanic ear appeared? |
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Definition
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Term
| Which frequencies can early mammals hear? Early reptiles? |
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Definition
| Mammals - high, reptiles - low |
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Term
| What are the main components of cochlea? |
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Definition
scala vestibuli
scala media
basilar membrane
scala tympani |
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Term
| What is the function of outer hair cells and how is this accomplished? |
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Definition
| Outer hair cells allow for cochlear amplification. Prestin, a motor protein, causes the hair cells to change length according to membrane potential. Depolarization causes prestin to contract pulling the tectorial membrane closer to the basilar membrane, which increases the bending of the basilar membrane and increasing the response of the inner hair cells. |
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Term
| What is the function of inner hair cells? |
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Definition
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Term
| What happens, when tilting towards kinozilium (big)? |
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Definition
| Depolarization, on the other direction - hyperpolarization |
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Term
| What is the difference between perilimph in scala media and scala tympany/vestibuli? |
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Definition
| There is a lot of K in media |
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Term
| Molecular mechanism of hearing |
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Definition
| Open of mechanosensitive channels -> influx of K+ -> influx of Ca -> depolarization -> repolarization by K+ outflux, as well as Ca |
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Term
| Are all channels closed in rest state? |
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Definition
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Term
| Is any threshold in channel activation? |
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Definition
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Term
| Depending on length and number of cilia, hair cells are tuned to different...? |
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Definition
| mechanical resonance frequencies |
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Term
| Depending on number and distribution of voltage sensitive Ca++-channels and Ca++-controlled K+-channels they show a specific ...? |
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Definition
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Term
| Where is hair cells, turned to higher resonance frequencies, are situated? |
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Definition
| At the end of basiliar membrane |
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Term
| Where frequency is mapped? |
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Definition
| frequency is mapped at the receptor surface |
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Term
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Definition
| Inner hair cells fire at specific frquencies depending on their location along the basilar membrane. Consequently, auditory afferent fibers fire at characteristic frequencies that vary with the location of their innervation of the basilar membrane. |
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Term
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Definition
| Phase locking refers to the consistent relationship between action potential firing in an auditory nerve fiber and the phase of the sound wave. |
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Term
| Describe phase locking at low frequencies. |
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Definition
| Firing occurs precisely aligned with each sound wave. |
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Term
| Describe phase locking at intermediate frequencies. |
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Definition
| Sound waves occur at an interval shorter than the absolute refractory period and volley coding becomes prominent. |
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