Auditory and vestibular system Flashcards
What are the two divisions of CN VIII?
Cochlear = sound Vestibular = head positions and movement.
Auditory & vestibular receptors are both innervated by _____.
CN VIII
The _______ is the outer most layer of the cochlea, vestibule and Semicircular canals.
Bony labyrinth
What lines the inside of the bony Labyrinth?
The membranous labyrinth = tube suspended in bony labyrinth.
- creates duct in each semicircular canal
- creates cochlear duct in cochlea
- 2 enlargements in the vestibule (Utricle & Saccule)
The _____ is the enlargement of the vestibule that is attached to the semicircular ducts.
Utricle
The _______ is the enlargement of the vestibule that is connected to the cochlear duct and utricle.
Saccule
Perilymph is found in the ______ and is similar to ______ in composition.
Bony labyrinth
CSF
Endolymph is found in the________ and is similar to ______ in composition.
Fills membranous Labyrinth
Similar to intracellular fluid
What produces endolymph?
Specialized cells of the Cochlea
*Resorbed in Endolymphatic sac
Meneires disease cause and symptoms?
- Obstruction of flow of endolymph in membranous labyrinth.
- transient attacks of vertigo, nausea, hearing loss and tinnitus.
______ are Auditory and vestibular receptor cells.
hair cells
_________ hair cells lack Kinocilium.
Cochlear
Hair cells have microvilli known as ________ arranged in graduated rows with ______ towards one side.
- Stereo cilia
- Tallest
Where does the Kinoculium reside?
near the tallest stereo cilia
- in the semicircular ducts, utricle & saccule *Not cochlear
How is receptor potential transduced?
gelatinous material at tips of kinocilium and stereo cilia. movement of G material causes deflection of stereo cilia.
Deflection toward the tallest stereo cilia causes what?
Depolarization of hair cell
Deflection away from tallest stereo cilia causes what?
Hyper polarization of hair cell
Deflection in perpendicular plane causes what?
Nothing!
________ moves perilymph.
Stapes
_______ & ______ convey airborne sound to fluid-filled inner ear.
Outer & middle ear
Tympanic membrane is _____ the size of the stapes footplate. What does this mean?
15x
= stapes vibrations have more force/unit area.
_______ pulls stapes away from oval window of the Cochlea, stiffening the Ossicular chain. What does this do?
Stapedius muscle (Innervated by VII) = Blocks sounds of own voice (Spasm can cause clicking sound in ear when speaking.)
_______ pulls the malleus in toward the middle ear, stiffening the ossicular chain. What does this do?
Tensor Tympani muscle (innervated by V)
= Blocks chewing sound; can anticipate loud sounds and cans spasm, causing tinnitus at low frequency.
What are the 3 structures of the Cochlea?
Scala Vestibuli (Sup.) Scala media (Med) Scala tympani (Inf)
________ is a perilymphatic space, continuous with vestibule.
Scala Vestibuli
(structure of cochlea)______ contains endolymph.
Scala media