Term
How many labyrythns are there in the Otic Capsule and name them |
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Definition
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Term
Describe the Bony Labyrinth |
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Definition
It is a a series of cavities within the petrous portion of the temporal bone |
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Term
Describe the Membranour Labyrinth |
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Definition
It is a series of soft tissue canals, sacs, and ducts within the bony labyrinth; follows the bony labyrinth in shape, but is smaller |
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Term
Name three components of the Bony Labyryth |
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Definition
Auditory System - Cochlea, Vestibular System - 3 Semicircular Canals, Vestibule |
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Term
What is the space between the osseous and membranous labyrinths called? What is it filled with? |
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Definition
Perlymphatic Space/ A fluid called Perilymph |
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Term
Describe perilymph and what is it similar to? |
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Definition
High in sodium (Na+) and low in potassium (K+); a chemical composition similar to that found in cerebral spinal fluid, but its source is not completely known |
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Term
What is the membrabous labyrinth filled with? |
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Definition
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Term
Describe endomymph. Where is it produced? |
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Definition
high in potassium (K+), and low in sodium (Na+). This fluid is produced by the stria vascularis, a structure found inside the cochlea. |
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Term
Is there any communication between the membranous labyrinth and the bony one? |
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Definition
No (think of inner tube inside tire |
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Term
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Definition
The auditory portion of the inner ear is called the COCHLEA. It is cone shaped and measures 5mm from its base to apex and 9mm across its breadth of the base. It is a coiled structure with 23/4 turns or coils that coil around a bony central canal called the MODIOLUS |
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Term
Describe the bony cochlea |
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Definition
The bony canal is about 35mm in length and narrows from base to apex. There are two major openings in the bony canal: the oval window and the round window |
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Term
Name the three scalae of the cochlea? |
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Definition
Scala Vestibuli, Scala Media, Scala Tympani |
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Term
Describe how the membranous labyrinth changes from base to apex as it follow the osseous labyrinth? |
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Definition
Instead of narrowing at the apex, it widens. It is also stiffer at the base, and flaccid at the but instead of narrowing at the apex, it widens. It is also stiffer at the base, and flaccid at the apex. |
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Term
What's another name for the scala vestibuli? |
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Definition
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Term
What is the bony scala filled with? Scala media? |
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Definition
The bony scalae are filled with perilymph and the scala media is filled with endolymph. |
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Term
About how many IHC are there? What shape are they? |
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Definition
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Term
About how many OHC are there? What shape are they? |
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Definition
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Term
Do OHC/IHC run longitudinally? Where do they run along? |
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Definition
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Term
Stereocilia are not of graduated height. T or F |
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Definition
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Term
Stereocilia contain which chemical? Why? |
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Definition
Actin for contracting and becoming stiff |
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Term
IHC have about how many stereocilia? What shape are they? |
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Definition
60 IHC shallow cresent-shaped |
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Term
OHC have how many stereocilia? What shape are they? |
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Definition
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Term
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Definition
Within the reticular lamina |
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Term
What is the tectorial membrane? What is it composed of? Where dows it project from? |
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Definition
A gelatinous mass overlying the OHC that is essentially transparent (90%) water. Projects from the spirous limbus. |
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Term
In the Tunnel of Corti, what cells surround it? Where do they sit? What are the OHC/IHC bathed in? How about the stereocilia? |
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Definition
Tunnel of Corti is surrounded by pillar cells which sit on the Basilar Membrane. OHCs and IHCs bathed in perilymph Stereocilia bath in endolymph |
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Term
What three elements is the Vestibular System composed of? |
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Definition
SEMICIRCULAR CANALS, the space between the canals and the cochlea known as the VESTIBULE, and the organs within it, the UTRICLE and the SACCULE. |
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Term
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Definition
5mm front to back and 3mm side to side. The osseous portion has numerous landmarks including recesses for various structures, and holes for nerve fibers to pass to the retrocochlear structures. |
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Term
What do the IHC/ OHC sit on? |
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Definition
Sensory Epithilium called the Crista |
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Term
Where are the stereo cilia embedded? |
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Definition
A gelatinous mass called the Cupula |
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Term
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Definition
A soft tissue structure housed in the vestibule |
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Term
Where do the semi-circular canals open? Where is this located? What liquid surrounds it and what's inside? |
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Definition
They open into the Utricle, which is located in the posterior-superior aspect of the vestibule. It's is surrounded by perilymph and is filled with endolymph |
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Term
What is the Macula? What covers it? |
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Definition
This is a flat plate where the sensory cells of the utricle sit. The cells are covered with a gelatinous substance containing calcium carbonate crystals or Otoliths. There are some supporting cells as well. |
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Term
Describe the Saccule in relation to the Utricle. Where does it lie? |
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Definition
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Term
What is the Ductis Reuniens? What does it do? |
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Definition
A short tube that is part of the membranous labyrinth and connects the vestibular organs to the cochlea |
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Term
Where does the Endolymphatic Duct lead in the brain? |
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Definition
It is extension of the membranous labyrinth into the dural area of the brain which leads to the endolymphatic sac |
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Term
Where does the perilymph of the bony labyrinth lead? Through what structure> |
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Definition
Connects to the cerebral spinal fluid through a narrow canal called the cochlear aqueduct |
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