Sponge: Set up Cornell Notes on pg. 59

Topic:

12.5: Middle Ear

Essential Questions:

1. Color code notes and Picture Bubble Map Figure 12.9

• Tympanic cavity• Malleus• Incus• Stapes• Auditory Tube• Oval window

2.1 Atoms, Ions, and Molecules

12.5: Middle Ear

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Our Amazing Hearing (4m32s)

2

3

Middle Ear

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• Tympanic cavity air-filled space in temporal bone

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Middle EarAuditory ossicles

• 3 small bones that vibrate in response to ear drum

• Transmit vibrations between the tympanic membrane and the inner ear

1. Tympanic membrane vibrates the malleus2. Malleus (hammer) vibrates the incus3. Incus (anvil) vibrates the stapes4. Stapes (stirrup) vibrates against the oval window 5. oval window moves fluids in

inner ear which stimulate the hearing receptors

Malleus

IncusStapes

How the Ear Works (3m25s)

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http://www.youtube.com/watch?v=qgdqp-oPb1Q

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Middle EarTympanic reflex

• Elicited in about 1/10 of a second following a loud external sound

• 2 small skeletal muscles contract, reducing the effectiveness in transmitting vibrations to the inner ear

• Reduces pressure from loud sounds that might otherwise damage the hearing receptors

• BUT, it cannot protect hearing receptors from loud sounds which occur rapidly

• Ex: explosion, gun shot

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Auditory Tube

Auditory Tube aka Eustachian Tube

•connects middle ear to throat•Allows air to pass between the tympanic cavity and the outside of the body by way of the throat and mouth• helps maintain equal pressure on both sides of tympanic membrane

• Necessary for normal hearing

• usually closed by valve-like flaps in throat

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Auditory Tube•Noticeable during rapid change in altitude

• Ex: High to low altitude• Air pressure on outside of tympanic membrane increases• Tympanic membrane is pushed inward, impairing hearing • Air will force its way up into the middle ear• This equalizes the pressure on both sides of the tympanic

membrane, moving it back into its rightful position• Causes a “popping” sound

• Swallowing, yawning, or chewing aid in the opening of the valves and can hasten equalization of air pressure

• Create Picture Bubble Map

• Color code to match notes

Pg. 58

Sponge: Set up Cornell Notes on pg. 61

Topic:

12.5: Middle Ear Infections

Essential Questions:

1. What is the major cause of middle ear infections?

2. What are some complications of ear infections?

2.1 Atoms, Ions, and Molecules

12.5: Middle Ear Infections

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13

Otitis Media “Ear Infection”Otitis Media aka “Middle ear infection”•Fluid builds up in middle ear

• Breeding ground for bacteria, which causes infection

•How? The mucous membranes that line the auditory tubes connect with the linings of the middle ear which creates a conduit for bacteria infecting the throat or nasal passages

• Greater in young children• Usually treated with antibiotics

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Otitis Media

Symptoms Causes Consequences Treatment

Pg. 61

Pictures

Pictures

Pictures

Pictures

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Ear Infection Symptoms• The main warning sign of infection is sharp ear pain. • You may be especially uncomfortable lying down, so you might

have a hard time sleeping. Other problems to look for:

• Trouble hearing• Fever• Fluid oozing from ears• Dizziness• Stuffy nose

Symptoms

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Fluid in the Ear• If the Eustachian (auditory) tube gets blocked, fluid builds up inside middle ear.• This makes the perfect breeding ground for bacteria and viruses, which can cause

infections. • Your doctor will look inside your ear with an otoscope, which can blow a puff of

air to make his eardrum vibrate. If the eardrum doesn’t vibrate as much as it should, chances are there’s fluid inside.

Causes

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1. Bursting an Eardrum• If too much fluid or pressure builds up inside your middle ear, the eardrum can

actually burst (shown here). • If that happens, you may see yellow, brown, or white fluid draining from the

ear.• Although this sounds scary, the eardrum usually heals itself in a couple of

weeks.• Unless it happens a lot, your hearing should be fine. The good news is that the

pain may suddenly disappear because the hole lets the pressure go

Possible Consequences

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2. Hearing Loss• If ear infections keep coming back, they can scar his eardrums and lead to hearing

loss, speech problems, or even meningitis. • If a person suffers from infections often, they might want to have their hearing

tested just in case.

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Treatment Options1. Antibiotics• using antibiotics both topical and oral

can provide you relief from earache by fighting the infection, as they stop swelling and itching of the ear.

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Treatment Options2. Myringotomy- An incision is made in the tympanic membrane• Tympanostomy tubes aka “ear tubes”

are Inserted into affected ears during surgery• Form a small tunnel so ears can

drain• Tubes usually fall out on their

own• Hopefully the child has outgrown

the susceptibility to ear infections

*This is only used in cases of chronic ear infections

Tympanostomy Tubes 1m 34s

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http://www.youtube.com/watch?v=iFLRR1j9Ps4

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Tonsils Can Be the Cause• Sometimes a child’s tonsils get so swollen that they put pressure on the

Eustachian tubes connecting her middle ear to her throat -- which then causes infections.

• If that keeps happening, the tonsils may have to be taken out

Use the video and the “All About Ear Infections” reading to add to your Otitis Media Tree-Map

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•DON’T forget to add pictures!• I want a FULL Tree-Map

Otitis Media Video4m30s

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http://www.youtube.com/watch?v=UBobShigoFk