Cochlear Anatomy & Mechanics Flashcards
What does the inner ear consist of?
- Cochlea
- Semicircular canals
- Initial portion of auditory nerve
What does the inner ear do?
- Translates mechanical vibrations into neural impulses
- Provides initial “decomposition” of sound by frequency
- Balance function
What is the size of the inner ear?
Roughly the size of pea
Where is the inner ear located?
It is contained in the petrous portion of the temporal bone
What does the bony labyrinth form?
The outer shell for the cochlea, three semicircular canals, utricle, and saccule (balance organs).
What is the inside of the cochlea made out of?
Membranous labyrinth
What does the membranous labyrinth aid in?
It keeps in all the fluids needed for proper functioning
Why is the cochlea encased in bone?
- The cochlea is an extremely delicate organ that needs protection from trauma
Temporal bone fractures normally affect?
Hearing and balance
The apex of the cochlea refers to?
The top end of the spiral
The base of the cochlea refers to?
The bottom, beginning of the spiral
The beginning or base of the spiral connects?
The round and oval windows to the middle ear
What is the average cochlea length from base to apex uncoiled?
3cm, just over an inch
What are the bony structures of the inner ear?
- Modiolus
2. Osseus Spiral Lamina
What is the modiolus?
The bony center of the coiled cochlea
What nerve runs through the modiolus?
The cochlear nerve runs through the middle of modiolus.
What is the osseous spiral lamina?
The bony ridge that extends from the modiolus toward the internal structure of the cochlea.
What type of neural projection does the osseous spiral lamina have?
Neural projections from the cochlear nerve to various parts of the cochlea
What are the internal three fluid-filled cavities structure of the inner ear?
- Scala Vestibuli
- Scala Media
- Scala Tympani
How are the cavities of the internal structure of the inner ear separated?
By two membranes:
- Reissner’s & Basilar
What membranes makes up the membranous labyrinth?
- Reissner’s Membrane
2. Basilar Membrane
The Reissner’s Membrane separates
Scala vestibuli from scala media
The Basilar Membrane separates
Scala media from scala tympani
How are the fluids of the cochlea concentrated?
With charged ions