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31 Cards in this Set
- Front
- Back
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Ear consists of:
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- External
- Middle - Internal |
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External ear and internal ear is separated by the...
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tympanic membrane
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Tympanic membrane is derived from:
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Ectoderm
Mesoderm Endoderm |
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Middle ear consists of:
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1. Ossicles ‑ malleus, incus, stapes
2. Muscles ‑ tensor tympani (CN V), stapedius (CN VII) 3. Oval window, round window |
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Internal ear is composed of...
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- two labyrinths
1. The bony labyrinth -series of spaces inside the petrous part of the temporal bone. 2. Membranous labyrinth (found within the bony labyrinth) |
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Bony labyrinth is filled with ...
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the perilymph (ExtraCellular Fluid)
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The bony labyrinth is made up of:
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1. Vestibule- Housing saccule and utricle
2. Semicircular canal- Housing semicircular ducts 3. Cochlea- Contains cochlear duct (scala media) |
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and the membranous labyrinth is filled with ...
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endolymph (IntraCellular Fluid)
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The membranous labyrinth is also called...
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= Cochlear duct
= Scala media |
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Cochlea contains...
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- cochlear duct (scala media)
- Makes two and one half turns around a bony core called modiolus |
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The spiral ganglion lies in the ...
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Modiolus
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Extending laterally from the modiolus is a thin bony ridge called the...
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osseus spiral lamina
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The cochlear duct subdivides the perilymph filled cochlea into:
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the superiorly located scala vestibuli
& the inferiorly placed scala tympani |
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What are the two scalae ?
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(tympani & vestibule)
-one long tube They communicate at the apex of the cochlea through an opening called helicotrema |
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the Spiral organ of Corti consists mainly of:
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PHP
- phalangeal cells - Hair cells - pillar cells |
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slide of cochlear duct
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Features of the Cochlear Duct:
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- Presence of stereocilia.
- Tips of these hair cells embedded in tectorial membrane. - Pillar cells occupies region between inner and outer hair cells thus, forming the inner tunnel. - contains spiral ganglion |
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Cochlear duct fx:
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This structure is important in sound transduction.
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Cochlear duct (membranous labyrinth) contains...
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spiral organ of Corti which lies on the basilar membrane
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Histological features of the cochlear duct:
Vestibular membrane separates... |
the scala media from the scala vestibule.
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Stria vascularis is responsible for
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the ionic composition of the endolymph.
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The organ of Corti (receptor for hearing) contains
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neuroepithelial hair cells -rests on the basilar membrane.
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Supporting cells and two types of hair cells can be distinguished as...
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outer and inner hair cells
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Sound comes from...
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- OVAL WINDOW SETS UP SOUND WAVES WITHIN COCHLEA
- SOUND WAVES causes VIBRATION OF THE ORGAN OF CORTI |
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Basillar membrane VS. Tectorial membrane
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BASILLAR MEMBRANE IS MORE ELASTIC THAN THE TECTORIAL MEMBRANE
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Vibration of the basillar membrane causes...
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the hair cells to bend by a shearing force as they push against the tectorial membrane
--> which in turn causes firing of the cochlear nerve |
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Internal ear consists of...
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Saccule and Utricle
Semicircular ducts |
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Saccule / Utricle are responsible for..
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Linear acceleration
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Saccule / Utricle consist of...
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Macula, Neuroepithelial (hair) cells, and Otoliths
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Semicircular ducts are important in...
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Angular acceleration + motion
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Semicircular ducts consist of...
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Cristae ampullares
Neuroepithelial (hair) cells Cupula |
