Anatomy of the Inner Ear and Cochlea Flashcards
inner ear versus the labyrinths
same thing
houses sensory ends organs of auditory and vestibular systems
inner ear
where are the labyrinths located
petrous portion of the temporal bone
anatomy of the inner ear is dominated by large fluid filled spaces which are essential for ________
signal transduction
what 2 primary components can the labyrinths be split into
1) bony labyrinth
2) membranous labyrinth
vestibule
cochlea
semicircular canals
- post., sup., lat. (horizontal)
bony labyrinth
maculae
utricle
saccule
cochlear duct
semicircular ducts
- post.,sup.,lat. (horizontal)
endolymphatic duct/sac
membranous labyrinth
what does bony labyrinth contain
perilymph
what does a membranous labyrinth contain
endolymph
typical extracellular fluid that is high in Na+ and continuous with CSF in subarachnoid space
perilymph
very atypical extracellular fluid that is high in K+ and has varying compositions throughout membranous labyrinth (result of K+ pumps) and communicates w/ venous structures of dura mater
endolymph
______ results from different compositions of perilymph and endolymph
endocochlear potential
endocochlear potential primary consists of ____ ions
K+
endolymphatic potential is approx. what at cochlea and varies through endolymphatic space
+85 mV
endocochlear potential provides the basis for _________ in sensory hair cells
signal transduction
resting membrane potential
-50mV
what are the two forces that endocochlear potential results from
1) active addition of K+ into endolymph
2) passive removal of K+ from hair cells
what is the oval shaped central portion of the bony labyrinth
vestibule
what communicates with cochlea, SCC, and middle ear space
vestibule in bony labyrinth
what receives incoming sound stimulus energy from the ME via the OW and dissipates that energy via RW
vestibule in bony labyrinth
what is the snail-shaped bony canal with a central bony axis called modiolus
cochlea in bony labyrinth
where does the association with the cochlear duct create 3 separate spaces or scale on cross section of the spiral
cochlea in bony labyrinth
what is elliptical in shape in the membranous labyrinth
utricle
what is connected to saccule via utriculosaccular duct and has a sensory epithelium called a macula
utricle in the membranous labyrinth
what has otolithic membranes that overlies macula to facilitate sterociliary deflection
utricle in the membranous labyrinth
what labyrinth is globular in shape and has the macula oriented in vertical plane
saccule in the membranous labyrinth
what is the scala media another name for
cochlear duct
what does the cochlear duct or scale media contain
sensory epithelium of the cochlea
what do semicircular ducts do
communicate with utricle and has dilation at one end called ampulla and contains crista ampullaris with a gel-like cupla over the crista ampullaris
what originates from the utriculosaccular duct
endolymphatic duct/sac
what is the site of endolymph removal to venous drainage
endolymphatic duct/sac
what fluid is found within the membranous labyrinth
endolymph
what tissue is responsible for special composition of endolymph
stria vascularis
where is the stria vascularis tissue located?
lining the lateral wall of the cochlear duct
________ can excess endolymph and be released and it [does/does not] imply that there is a natural “flow” of endolymph through the membranous labyrinth
stria vascularis; does
what are the inner ear structures that house sensory epithelia
organ of corti
(1) saccule
(1) utricle
(1 for each) ampulla
CN VIII (vestibulocochlear nerve) and the CN VII (facial nerve)
the structures that pass through the internal auditory meatus
the organ of Corti
