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? |
|
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? |
|
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? |
|
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? |
|
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? |
|
Definition
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Term
|
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? |
|
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
|
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? |
|
Definition
| Sensory Epithilium called the Crista |
|
|
Term
| Where are the stereo cilia embedded? |
|
Definition
| A gelatinous mass called the Cupula |
|
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Term
|
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? |
|
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? |
|
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. |
|
|
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? |
|
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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