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Anatomy and Physiology of the Ear. 3 Parts of the Ear Outer, Middle, and Inner Ear. Part 1 OUTER EAR- Pinna to Tympanic Membrane The “pre amp” –makes sound waves stronger. Does Ear Wax Have a Purpose?. 2 important functions 1.Keeps skin in ear canal soft 2. Keeps bugs out
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3 Parts of the EarOuter, Middle, and Inner Ear • Part 1 OUTER EAR-Pinna to Tympanic Membrane The “pre amp” –makes sound waves stronger
Does Ear Wax Have a Purpose? 2 important functions 1.Keeps skin in ear canal soft 2. Keeps bugs out (they don’t like the taste)
What Causes Outer Ear Hearing Loss ? • Wax pushed up against eardrum (tympanic membrane) from q-tip use • Sharp objects that puncture tympanic membrane • Born with damaged ear canal or without pinna • Swimmer’s Ear - what is that?
Swimmer’s Ear • Water + • Germs or bacteria + • Wax in the auditory canal = mold • Complications • How to treat it????
Healthy TM is translucent is silvery in color Red or pink or bulging shows an infection. Tympanic Membrane
Part 2 - Middle Ear • Sound waves change to mechanical energy in the middle ear • ½” chamber
What are the parts of the Middle Ear? • Back of tympanic membrane • 3 small bones • Eustachian tube
Eustachian Tube • What is the purpose? • Drain cells/tissue • Equalize air pressure
What Causes Hearing Loss in the Middle Ear ? • Calcium deposits on bones Solution ? • Loud sudden noises- firecracker, gunshot Solution? • Trauma to the head- fall, car accident • Otitis media- what is that???
Otitis Media • Most common ailment for children- Why??? • Germs travel up eustachian tube-lodge in middle ear
Why are Parents concerned? • Ossicles do not vibrate correctly = 25dB hearing loss • Critical time for learning langauge • Treatments??
Antibiotics • Children over medicated? • Will condition improve by itself? • Are new strains of bacteria developing? • Risks for developing speech?
Ear Tubes- Chronic Otitis MediaSmall slit made in TM and tube put in for drainage from Middle Ear- most tubes fall out after a few months
The voice YOU hear? Sorry- you’re the only one who hears it Why? The voice on a tape? This is your voice to the world Which is your “real voice”?
CONDUCTIVE HEARING LOSS • Any hearing loss occurring in the OUTER or MIDDLE EAR • Examples ????? • Malformed pinna, too much wax, swimmers ear (or water stuck in ear), torn tympamic membrane,Otitis media, calcium deposits on ossicles, torn muscles that control the ossicles Conductive Hearing Loss can be repaired
The Inner Ear • Cochlea • semi- circular canals • auditory nerve (8th cranial nerve) • Note the changes of energy as the sound waves come through each part of the ear
The 3 bones vibrate causing a disturbance at the “Oval Window”
Parts of the Inner Ear • Cochlea • Semi-circularCanals • Auditory (8th cranial) nerve
Why do you get dizzy? • Liquid in Semi –Circular canals • Information from cilia sent to brain • Must match info sent from eyes • Dizzy = brain doesn’t know what to follow
The COCHLEA • Size of a pea • Fluid –filled • Contains up to 20,000 cilia or hair-like nerve endings
Movement of the fluid stimulates the cilia • Creates Electrical impulses
Auditory nerve- carries electrical impulses from cilia (in cochlea and semicircular canals) to the brain for interpretation
Sensorineural Hearing Loss(Hearing loss in the Inner Ear) Known etiologies- • Multiple Sclerosis • Leukemia • Sickle cell • syphilis • Bacterial infection( meningitis) • Mumps • ototoxic drugs (aspirin) • tumor (from cell phones?) • noise explosion • menieres disease • genetic connexin 26 • toys- noise levels • membrane rupture • airbag (ruptures tympanic membrane, tinnitus hearing loss) • Premature birth • unknown
Review--Pathway of Sound • Sound waves enter pinna travel through auditory canal • Sound waves strike tympanic membrane causing vibrations (mechanical energy) • Vibrating TM causes ossicles to vibrate • Vibrating stapes bone at oval window generates movement of cochlear fluid (Hydralics) • Fluid movement stimulates cilia- lined cochlea • Cilia sends electrical impulses along auditory nerve to brain for interpretation