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• 50: 12.3 Clinical Application Smell and Taste Disorders• 54: Lab 31 Smell and Taste Lab• 55: Hearing Case Study: No More Loud Music
(Read/Highlight/Questions)• 56: External Ear Picture (color-coded---
Functions)• 56: Now Hear This: Don’t Remove Earwax
(Read/Highlight/Questions)• 58: Middle Ear Picture (color-coded---Functions)• 60: All About Ear Infections (ONLY Highlight)• 62: Inner Ear Picture (color-coded---Functions)
Tape in Notebook 5 mins
Sponge: Set up Cornell Notes on pg. 63
Topic:
12.5: Major Parts of the Inner Ear
Essential Questions:
Picture Bubble Map of Inner Ear:• Cochlea• Semicircular canals• Osseous Labyrinth• Membranous Labyrinth• Vestibule• Vestibulocochlear Nerve
2.1 Atoms, Ions, and Molecules
12.5: Major Parts of the Inner Ear
QUIZ: On MONDAYLabeling the parts of the external, middle, and inner ear
Extra Credit:• IB Art Show @ mall• Little Mermaid • Tonight 6pm • Sat 2pm
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Inner Ear
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Inner EarThe Inner Ear is a complex system of labyrinths
• Osseous (bony) labyrinth • rigid outer wall of inner ear• secretes perilymph which
conducts sound vibrations
• Membranous labyrinth• tube within osseous
labyrinth• filled with endolymph which
conducts sounds• Houses receptor cells for
hearing and equilibrium
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Inner EarThree Parts of Labyrinths:
• 1. Cochlea (coke/le/ah) or (Kok/le/ah)
• functions in hearing
• 2. Semicircular canals• provides a sense of
equilibrium
• 3. Vestibule• functions in
equilibrium AND hearing
cochlea
Semicircular canals
vestibule
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The Vestibulocochlear Nerve:Aka acoustic or auditory nerve
• Has two branches:
1. vestibular branch: senses changes in the position of the head to maintain equilibrium
2. cochlear branch: send signals to brain where sound can be interpreted
Cochlea
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ScalaVestibuli
ScalaTympani
Cochlear Duct
Vestibular Membrane
Basilar Membrane
Organ of Corti
• Leave a little room for info about cochlea
Pg. 62
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CochleaCochlea• Functions in hearing• Shaped like a snail• Coiled around a bony core (modiolus)
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CochleaScala vestibuli
• upper compartment of cochlea• leads from oval window to apex of spiral• conducts sound vibrations to the scala media (cochlear duct)• contains perilymph
Oval window
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CochleaScala tympani
• lower compartment• extends from apex of the cochlea to round window• allows the vibrations to escape into the air of the tympanic cavity• contains perilymph
Round window
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CochleaVestibular membrane
• separates cochlear duct from scala vestibuli
• Separates endo/perilymph• Diffusion barrier- allows
nutrients to travel from perilymph to endolymph
Cochlear duct aka scala media• lies between the scala vestibuli
and scala tympani• Filled with endolymph• Houses the organ of Corti
Basilar membrane• separates cochlear duct from
scala tympani• Floor of cochlear duct• Separates the endo/perilymph
Scala Vestibuli
Scala Tympani
endolymph
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Organ of Corti***Organ of Corti***:•Hair cells: hearing receptor cells located here •on upper surface of basilar membrane•Different frequencies of vibration move different parts of basilar membrane•Sound frequencies cause hairs of receptor cells to bend•Simulates the vestibulocochlear nerve which will send the signals to the brain for interpretation
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Tympanic Membrane Cochlea Incus Tympanic Cavity AuricleStapes Round Window Malleus Auditory Tube
Semicircular Canals Vestibulocochlear Nerve External Acoustic Meatus
Label this diagram of the Ear*Quiz on Mon.
Pg. 62
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Tympanic Membrane Cochlea Incus Tympanic Cavity AuricleStapes Round Window Malleus Auditory Tube
Semicircular Canals Vestibulocochlear Nerve External Acoustic Meatus
Label this diagram of the Ear*Quiz on Mon.
Pg. 62
Auricle
Incus
malleus
Tympanic membrane
stapes
Semicircular canals
cochlea
Vestibulocochlear nerve
Round window
Tympanic cavityAuditory tube
External acoustic meatus
Sponge: Set up Cornell Notes on pg. 65
Topic:
12.5: How Sound Travels Through the Inner Ear
Essential Questions:• NONE.
2.1 Atoms, Ions, and Molecules
12.5: How Sound Travels Through the Inner Ear
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Ear Labeling Quiz Time 15pts
13. 14. 15.
1. The stapes vibrations enter the perilymph at the oval window 2. Travel along the scala vestibuli3. Enter the endolymph of the cochlear duct4. Move the basilar membrane
a. Causing the hair cells in the Organ of Corti to bendb. Send signals along the vestibulocochlear nerve to the brain
5. Vibrations enter the perilymph of the scala tympani6. Forces are dissipated into the air in the tympanic cavity
DON’TWRITE
1. Sound waves vibrate the tympanic membrane2. The tympanic membrane vibrates the auditory ossicles3. The vibrations enter the perilymph (fluid in the scala vestibule and scala tympani) at the oval window 4. Travel along the scala vestibule (top compartment of cochlea)5. Enter the endolymph (fluid in the cochlear duct) of the cochlear duct6. These vibrations move the basilar membrane
a. Frequencies cause organ of corti to bend against the tectorial membrane
b. Vesicles in hair cells release neurotransmittersc. Neurotransmitters stimulates the ends of nearby sensory nerve fibersd. Impulse travels along the cochlear branch of the vestibulocochlear
nervee. To the medulla oblongataf. Through the midbrain g. To the thalamush. Into auditory cortices of the temporal lobes of the cerebrum
(BRAIN) where they are interpreted7. Vibrations enter the perilymph of the scala tympani8. Forces are dissipated into the air in the tympanic cavity by movement of the round window
Inner Ear Animation Video
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Cochlear Implant
• Implant placed under skin above the ear
• Leads to electrodes placed near auditory nerve in the cochlea
• Wear a head set that has a microphone to pick up incoming sounds
• Sends electrical signals to cochlea
• Auditory nerve is stimulated
8 mo. Old Deaf Baby with Cochlear Implants 49s
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http://www.youtube.com/watch?v=HTzTt1VnHRM
Clinical Application 12.4:Getting a Cochlear Implant