Term
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Definition
A: Helix
B Triangular fossa
C: Antihelix
D: Crura of antihelix
E: Crura of helix
F: Concha
G: Tragus
H: Antitragus
I: Opening of external acoustic meatus
J: Lobule |
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Term
| What are the main functions of the pinna? |
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Definition
| The externalisation and localisation of sound. |
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Term
| What are the main functions of the ear canal? |
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Definition
1) Protects sensitive machinery
2) Walls secrete waxy cerumen which captures foreign bodies
3) It has some amplifying effect on sound frequency in the speech range. |
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Term
| What is an infection of the middle ear behind the tympanic membrane called? |
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Definition
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Term
| What makes children especially susceptible to otitis media with effusion? |
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Definition
| The straightness of their eustachian tube. |
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Term
| What is the function of the eustachian tube? |
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Definition
| It is connected to the nasopharynx; swallowing allows the innner and outer ear pressure to equilibrate. |
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Term
| What are the 3 bones of the inner ear? |
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Definition
1) Malleus
2) Incus
3) Stapes |
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Term
| What is the main role of the middle ear? |
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Definition
| To aid the passage of soundwaves into the fluid of the inner ear. |
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Term
| How is the air-fluid mismatch overcome in the middle ear? |
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Definition
| The stapes is smaller than the tympanic membrane (=increased pressure) and the ossicles act as levers together. |
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Term
| What is the role of the stapedius muscle? |
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Definition
| It stiffens the ossicular system. |
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Term
| Where does the tensor tympani attach? |
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Definition
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Term
| What does a Rinne test examine? |
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Definition
| Whether the patient has a conductive hearing loss. |
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Term
| What is a -ve Rinne test? |
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Definition
| Bone conducted sound is heard louder or longer than air conduction. |
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Term
| What membrane seperates scala vestibuli from scala media? |
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Definition
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Term
| What membrane seperates scala tympani from scala media? |
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Definition
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Term
| Where would you find perilymph? |
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Definition
| Scalae vestibuli and tympani. |
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Term
| Where would you find endolymph? |
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Definition
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Term
| What is the composition of endolymph? |
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Definition
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Term
| What is the composition of perilymph? |
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Definition
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Term
| Where do low frequencies most displace the basilar membrane? |
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Definition
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Term
| Where do high frequencies most displace the basilar membrane? |
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Definition
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Term
| What does a bend towards the tallest stereocilium cause? |
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Definition
| An incresased flow of K+ ions leading to depolarisation. |
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Term
| What does a bend towards the shortest stereocilium cause? |
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Definition
| A reduced flow of K+ ions leading to hyperpolarisation. |
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Term
| What is the role of prestin? |
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Definition
| Depolarisation of the outer hair cells causes prestin to be activated and to cause the hair cells to contract. Conversely, hyperpolarisation causes the cells to elongate. |
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Term
| What is the importance of outer hair cells? |
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Definition
| They accentuate the movements of the basilar membrane. |
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