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93 Cards in this Set
- Front
- Back
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What are the three chambers of the cochlea?
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Scala tympani
Scala media Scala vestibuli |
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Hollow core
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Modiolus
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The crainial nerve that sits in the modiolus is the...
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cochlear division of the VIIIth cranial nerve
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lLedge of bone that spirals around the modiolus and is atatched like a spiral ramp.
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osseous spiral lamina
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The scala vestibuli is continuous with the...
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vestibule
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The kind of fluid in the scala vestibuli and the scala tympani is called...
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perilymph
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The kind of fluid in scala media is called...
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endolymph
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At the apex of the cochlea is an opening called the... where the scala vestibuli and the scala tympani are continuous.
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helicotrema
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Which scala terminates at the round window?
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scala tympani. the round window membrane keeps the perilymph in.
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Name the two membranes that keep the scala media seperated from the other two...
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Reissner's membrane, or vestibular, separatesfrom the scala vestibuli and has flat cells.
The basilar membrane separates from the scala tympani and is a layer of radially oriented connective tissues. |
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The organ of Corti lies on which membrane?
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basilar membrane
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The cochler duct is another name for...
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scala media
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A ridge of fibrous connective tissue lying on the scala vestibuli surface of th osseous spiral lamina.
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spiral limbus
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Where does the basilar membrane extend to?
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It extends from the free edge of the osseous spiral lamina to the part of the spiral ligament on the tympani side.
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An area of fibrous connective tissue against the outer bony wall of the cochlear turns.
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Spiral Ligament
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The cell type in Reissner's membrane
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squamous cells.
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Three layers thick and containing numerous blood capillaries. Lies against the spiral ligament and borders the endolymph.
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stria vascularis
*fun fact- most metabolically active part of the cochlea. |
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Outpocketing of cells between the stria vascularis and the basilar membraine
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spiral prominence
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Single layer of low cuboidal cells that extend from the spiral prominence to the organ of Corti.
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outer spiral sulcus cells
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The epithelium continues along the edge of the spiral limbus as single layer of cuboidal cells called...
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inner spiral sulcus cells
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Cells on the upper endolymphatic surface of the spiral limbus.
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Interdentate cells
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A single row of these cells lie on the osseous spiral lamina and support each inner hair cell.
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inner supporting cells
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Stereocilia have roots in the ...and extend to the...
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cuticular plate
subtectorial space (endolymph beneath the tectorial membrane) |
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What lies between the inner and outer pillar cells?
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tunnel of Corti
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These cells have a cup shaped depression that supports the base of a hair cell.
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Deiters' cells
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The inner supportigng cells. pillar cells and Deiters' cells form an impenetrable surface called the...
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recticular lamina
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What are the three types of border cells in the organ of Corti?
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Hensen's Cells- next to Deiters' Lateral OHC and medial to Claudius. Tall support.
Claudius' Cells- between Hensen's and outer spiral sulcus cells/spiral ligament. Columnar in several rows Boettchers' Cells are only on spiral turns. |
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Where does the tectorial membrane attach?
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The interdentate cells on the spiral limbus and over the organ of Corti
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Which hair cells does the tectorial membrane make contact with?
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Outer hair cells- the longest stereocilia to its under surface
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What are the parts of the vestibular system?
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semicircular canals (cristae ampularis)
vestibule (otolith organs) |
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What is the fuction of the vestibular system of the inner ear?
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picks up, analyzes and transmits position of body in space- angle, direction, velocity
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What is the fuction of the auditory system in the inner ear?
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spectral analysis of sounds for f, I and temporal
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Bony case that holds sensory organs
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Osseous labyrinth
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Membrane holds fluid in which rest the sensory end organs
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Membranous labyrinth
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Osseous Labyrinth is a system of canals and spaces in the...
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petrous portion of Temporal Bone
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What are the three divisions of the Osseous Labyrinth?
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Vestibule
Semicircular canals Cochlea 2 and ¾ turns |
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What does the Vestibule hold? What is it medial to?
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otolith organs (utricle and saccule)
oval window |
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What is the diameter of the Vestibule?
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4 mm diameter
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What are the names of the three Semicircular canals? Diameter?
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superior, posterior, lateral
3 mm by 1 mm in diameter |
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Joins cochlea and saccule connecting vestibular and auditory systems
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Ductus Reuniens (duct of Hensen)
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Endolymphatic duct (utriculosaccularis)
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duct where utricle and saccule join
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The Endolymphatic duct passes through this to join the endolymphatic sac
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vestibular aqueduct
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A pouch sitting in dura matter
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endolymphatic sac
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modiolar side, thickened periosteum, rests on osseous spiral lamina
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Limbus
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Top of limbus to outer canal wall
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Reissner’s Membrane
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Attaches lip of limbus to form internal spiral sulcus
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Tectorial Membrane
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Spiral lamina to spiral ligament thin on modiolar side
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Basilar Membrane
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band of connective tissue on outer wall
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Spiral Ligament
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inside spiral ligament-nutrition
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Stria Vascularis
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Where does the Spiral Lamina terminate?
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hamulus (hook) making
helicotrema (opening scala vestibuli to tympani) |
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Opening for NVIII fibers exit
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habenula perforata
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Sensory end organ for hearing
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Organ of Corti
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Form a tunnel joined at top – Arch of Corti
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Pillars (rods) of Corti
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Separate IHC from OHC
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Pillars (rods) of Corti
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The fibers from what nerve traverse tunnel of Corti to contact OHC?
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XIII
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What are the attachments of the Tectorial Membrane?
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Lip of limbus-strong attachment
Fragile attachment to Hensen’s cells |
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What the deminsions of the basilar membrane?
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Narrow at basal end (.04 - .16 mm) to wide (.5 mm) at apex
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Where is the basilar membrane the stiffest?
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Stiffer near oval window
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How many rows of inner hair cells are there?
How many outer hair cells rows? |
1
3 |
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What shape are inner hair cells?
What shape are outer hair cells? |
U
W |
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How are the shapes of inner hair cells different from outer hair cells?
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Inner hair cells are rounded based and out hair cells are test tube shaped.
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How many inner hair cells and outer hair cells are there?
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inner- approximately 3500
outer- approximately 12 to 20,000 |
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How many stereocilia are in the inner hair cells and the outer hair cells?
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inner- 50 stereocilia
outer- 40-150 |
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How many neurons are innervated to one IHC?
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Twenty
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What % of afferent fibers are connect to IHC? Efferent fibers?
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95%
5% |
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How many neurons are connected to the OHC.
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One neuron connected to many OHCs
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Thickened periosteum that rests on the osseous spiral lamina
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limbus
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Attaches to the lip of the limbus to form the internal spiral sulcus
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tectorial membrane
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The spiral lamina ends at the ---- forming the helicotrema.
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hamulus
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Cells that run from the spiral ligament to the Hensen cells. Columnarin several rows
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Cladius
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AKA outer pharengeal cells
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Dieter's cells
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Tall cells lateral to the OHC
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Hensen
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Support for IHC allong with Inner phalangeal cells.
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Border Cells of Held
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Fills Tunnel of Corti
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cortilymph
NA+ |
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Cell bodies in the spiral ganglia in the modiolus
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NVIII
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78mm^3
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perilymph
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2.5mm^3
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endolymph
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Where does the perilymph terminate?
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cochlear aqueduct to subarachnoid space
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The vestibular aqueduct leads to....
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endolymphatic duct and sac in dura matter
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If there was no charge bc the endolypmh and perilymph mixed woult that be bad?
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yes
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The tectorial membraneis more stiff near the...
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base. frequency coding!
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Describe the traveling wave theory
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Motion is complex and the shape of the envelope simplifies. sharper at high frequencies.
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At low intensities, Outer hair cells move
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electromotility
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Cochlear amplification from outer hair cells are for dB up to
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40-60dB
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Clinical test based on outer hair cell motility
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otoacoustic omissions
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What are the 4 Electrical Potentials of the Inner Ear
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Cochlear Microphonic, Summating Potential, Resting Potential, Action Potential
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Thus, the summating potential is a _______ ____________ response which follows the _______ pattern of the acoustic wave rather than the wave form pattern.
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DC electrical, envelope
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The Summating Potential is possibly due to longitudinal bending or shearing of primarily __________ __________ cells in the direction of the ________ of the cochlear partition, as opposed to radial bending or shearing forces.
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inner hair, length
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inner hair, length
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Resting Potential
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It is thought that the _____ ____________ is responsible for the positive resting potential of endolymph since this positive potential is non-existent in the endolymph of the ________ _____________.
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It is thought that the _____ ____________ is responsible for the positive resting potential of endolymph since this positive potential is non-existent in the endolymph of the ________ _____________.
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The action potential (AP) in a nerve, including the cochlear branch of the VIII nerve, is a short sudden change in _______ which moves at a constant _____ along the length of the _______ at great speed.
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charge, amplitude, nerve
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Electrocochleography
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Measure sound out of round window- know membranes are in tact.
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Auditory evoked potentials
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5-6 msec to brain stem
15-50 msec MLR (auditory cortex) 300 msec to cortical respose |
