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Tape in Notebook
5 mins
• 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) 1
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
12.5: Major Parts of the Inner Ear
2.1 Atoms, Ions,
and Molecules
QUIZ: On MONDAY
Labeling the parts of
the external, middle,
and inner ear
Extra Credit:
• IB Art Show @ mall
• Little Mermaid
• Tonight 6pm
• Sat 2pm
Inner Ear
3
Inner Ear
4
Inner Ear
The 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
5
Inner Ear
Three Parts of Labyrinths:
Semicircular
canals
•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
vestibule
6
cochlea
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
7
Cochlea
Pg. 62
• Leave a little room for info about cochlea
Organ
Scala
Scala Cochlear Vestibular Basilar
Vestibuli Tympani Duct Membrane Membrane of Corti
8
Cochlea
Cochlea
• Functions in hearing
• Shaped like a snail
• Coiled around a bony core (modiolus)
9
Cochlea
Scala 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
10
Cochlea
Scala 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
11
Cochlea
Vestibular 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
endolymph
Scala
Vestibuli
Scala
Tympani
12
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
13
Pg. 62
Label this diagram
of the Ear
*Quiz on Mon.
Tympanic Membrane
Cochlea
Incus Tympanic Cavity
Auricle
Stapes Round Window
Malleus
Auditory Tube
Semicircular Canals
Vestibulocochlear Nerve
External Acoustic Meatus14
Pg. 62
Incus
stapes
malleus
Auricle
Tympanic
membrane
Label this diagram
of the Ear
*Quiz on Mon.
Semicircular
canals
cochlea
Vestibulocochlear
nerve
Round window
External acoustic
meatus
Auditory tube
Tympanic cavity
Tympanic Membrane
Cochlea
Incus Tympanic Cavity
Auricle
Stapes Round Window
Malleus
Auditory Tube
Semicircular Canals
Vestibulocochlear Nerve
External Acoustic Meatus15
Sponge: Set up Cornell
Notes on pg. 65
Topic:
12.5: How Sound Travels
Through the Inner Ear
Essential Questions:
• NONE.
12.5: How Sound Travels Through
the Inner Ear
2.1 Atoms, Ions,
and Molecules
Ear Labeling Quiz Time
13.
14.
15pts
15.
17
1.
2.
3.
4.
5.
6.
The stapes vibrations enter the perilymph at the oval window
Travel along the scala vestibuli
Enter the endolymph of the cochlear duct
Move the basilar membrane
a. Causing the hair cells in the Organ of Corti to bend
b. Send signals along the vestibulocochlear nerve to the brain
Vibrations enter the perilymph of the scala tympani
Forces are dissipated into the air in the tympanic cavity
DON’T
WRITE
1. Sound waves vibrate the tympanic membrane
2. The tympanic membrane vibrates the auditory ossicles
3. 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 duct
6. These vibrations move the basilar membrane
a. Frequencies cause organ of corti to bend against the tectorial
membrane
b. Vesicles in hair cells release neurotransmitters
c. Neurotransmitters stimulates the ends of nearby sensory nerve fibers
d. Impulse travels along the cochlear branch of the vestibulocochlear
nerve
e. To the medulla oblongata
f. Through the midbrain
g. To the thalamus
h. Into auditory cortices of the temporal lobes of the cerebrum
(BRAIN) where they are interpreted
7. Vibrations enter the perilymph of the scala tympani
8. Forces are dissipated into the air in the tympanic cavity by movement of the
round window
Inner Ear Animation Video
29
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
30
Cochlear Implants 3m7s
31
8 mo. Old Deaf Baby with
Cochlear Implants 49s
http://www.youtube.com/watch?v=HTzTt1VnHRM
32
Bionic Ears
Start at (4m42s)
4m10s
33
Clinical Application 12.4:
Getting a Cochlear Implant