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111 Cards in this Set
- Front
- Back
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Acoustics is:
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The study of physical or psychological sound.
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What is Sound?
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*The disturbance of molecules (particles) within and propogated through an elastic medium (solid, liquid, gas)
*There are 3 components needed in order for sound to be produced -Vibration (smallest component of sound) -Mass with a capability to vibrate -Force (source, force and air) |
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Medium of Air
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particles are very tiny, and if we could see them, they'd bounce back and forth <-->
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Brownian Motion
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*Rapid and random movements of molecules in the air due to heat
*Since there is always heat (or friction) in a gas medium, there is always Brownian Motion. Heat is not hot or cold, it's friction. *More heat results in more rapid movements, while less heat results in slower movements. Increase heat, increase molecular motion. *It's exclusive to gas* |
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Anotia
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Without a pinna. No hearing loss, but trouble w sound direction.
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Microtia
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Small under-formed pinna. no hearing loss.
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Atrisia
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No ear canal, or without a developed ear canal. Does result in hearing loss.
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Stenosis
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abnormal narrowing of the ear. does not result in hearing loss.
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External otitis
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inflammation of the ear in the EAM (external auditory meatus). Swimmers ear. Term used to be just inflamation due to bacteria in the ear, now it's a catch-all term. EAM is dark, warm and moist. Otalgia (pain in ear that doesn't cause hearing loss)
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Otomycosis
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Fungal infection. Usually yellow or white in color. Otalgia (pain in ear that doesn't cause hearing loss)
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Furunculosis
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Hair follicle becomes inflamed in the outer part of the ear. (hint: fur=hair) Otalgia (pain in ear that doesn't cause hearing loss)
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Necrotizing Otitis
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Death of ear tissue. Can be life threatening. Otalgia (pain in ear that doesn't cause hearing loss)
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Tympanic Sclerosis
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Scar tissue on tympanic membrane.
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Cauliflower Ear
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Wrestlers ear, looks gross. Otalgia (pain in ear that doesn't cause hearing loss)
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Eustacian Tube Dysfunction
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Pressure, air, stuffiness, no drainage. Eustachian tube equalizes pressure, is drainage, aerates ear. This dysfunction is a precurser to other similar dysfunctions. Occurs naturally in kids bc of short, level Eustachian tubes. Tonsilitis or adenoiditis can cause this too.
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Otitis Media
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Generic term for inflammed middle ear. 85% of kids experience. if you have one, your 66% likely to get another. kids with Downs syndrome or cleft are more likely to get this.
*stuff shed begins to build up in the middle ear. can't drain (only holds 2 cc) Cause: either bacterial or fungal |
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Serous OM
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1st stage of OM. Sterile. Mucus has no where to drain, No symptoms. Hear like your under water. Often it's not discovered in infants until a well child visit.
Cause: either bacterial or fungal |
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Acute OM
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Sudden onset of pain. Sudden agent gets into middle ear. Kid cries, fever, treatment is antibacterial or antibiotic. or watchful waiting.
Cause: either bacterial or fungal |
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Chronic OM
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Swelling doesnt go away. Infection does, but fluid is always there. Doesn't come out on own. Need surgical intervention. Can cause hearing loss.
Cause: either bacterial or fungal |
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Myringotomy
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Surgical intervention-perforates the TM and get pressure equalization tubes. They are artificial Eustachian tubes.
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Adhesive OM
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Mucus so viscus it sticks to everything. Result of chronic OM. Very sticky, can cause hearing loss bc TM does not vibrate.
Cause: either bacterial or fungal |
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Barotrauma
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When ear fills w/ blood caused by a very drastic change in pressure (like sky diving). Taste blood in throat. Feels good to relieve pressure. No need for hospital unless blood comes out of ear & pain.
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Complications-Mastoiditis
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Mastoiditis prior to antibiotic-infection in mastoid portion of skull bone. Harder to treat.
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Complications-Cholesteatoma
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Growth in middle ear only detect when errodes and comes out of ear. Surgery is the only option.
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Complications-Otosclorosis
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"ear hardening" happens at ossicular chain. Stapes becomes fixated. Not lever action in one or both ears.
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See Diagrams
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TM, Pinna, ossicular chain.
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Inner Ear
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Portion of the ear that converts mechanichal energy into electrochemical energy.
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Occlusion effect
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Perception of increased loudness of a bone-conducted tone when the outer ear is occluded
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Sensorineural Hearing Loss
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Loss of hearing bc of damage to the inner ear or auditory nerve
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Def. of anatomy and physiology
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A-the way an organism is made
P-the way an organism functions |
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Middle ear
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Air filled, holds three smallest bones of the body in ear.
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Cochlea
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Portion of the inner ear responsible for hearing function
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Bone Conduction
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Transmission of sound to inner ear by vibrations in the skull
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Attenuation
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reduction in energy
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Auditory Nerve
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VIII cranial nerve connects inner ear with brain
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Conductive Hearing Loss
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Loss of sound sensitivity bc of damage to the outer or middle ear (conduction=through air)
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Sound Waves
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The sucessive back and forth movement of molecules. Many types. Need source and force. Compress and refract.
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Transverse Wave
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molecular motion perpendicular to direction of wave. pebble in water.
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Longitudinal Wave
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molecular motion moves in same direction of wave. Speaking.
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Sine Wave
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Graphic rep. of sound wave in purist form. Once oscillation comprised of 1 compression, 1 rarefaction.
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Properties of Vibratory Movement
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*Displacement-any point along sine wave not at rest
*Amplitude-Maximum displacement (loudness) *Frequency-how many times obj vibrates. 1 sine wave is 1 CPS (cycle per second) or Hz *Period and frequency inversly proportional. P=1/f *Phase-distance between two waves |
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Energy: Kinetic & Potential
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Think in terms of force.
Kinetic-when you impart force on object. away Potential-when pendulum moves back toward source |
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Free Vibration / Friction
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mass vibrates until all energy dissipates. friction determines how fast energy dissapates. Depends on medium. air vibrates more than steel.
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Damping
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Cessation of energy of vibrating body. Critical damping is when oscillation stops before it completes one full cycle. Auditory system is critically damped.
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Forced Vibration
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outside force cause the "free vibration" system to continue.
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Resonance / Resonant Frequency
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-the ability of a mass to vibrate at a particular frequency with minimal force. Resonant F: when mass vibrates with least amount of external force.
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Frequency Affected By:
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Length-add, lower freq. shorten, higher freq.
Mass-more=lower freq. Stiffness=guitar. stiffer/tigher=higher. |
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Wavelength & Velocity
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w-charact. of sound related to freq. lower freq have much longer wavelengths. w=v/f
v-how fast wave moves though the medium. 1130 ft/sec in air. |
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When a soundwave encounters an object:
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Transmission-wave encounters object and loses no energy
Diffraction-sound bends, changes frequencies. pos and neg. Reflection-sound bounced back. can create another wave. Absorption-damping or soften a sound. Interference |
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Interference
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constructive=good (sound waves join to increase amplitude)
destructive-bad (phase out and destroy portions of the sound-can cancel pure tone) |
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Complex Tones
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periodic (music) is not complex. aperiodic (crash) is. Contain different frequencies. Aperiodic do not have fundamental frequencies.
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Harmonics and Overtones
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Whole # multiples of the fundamental frequency in periodic tones. only difference between the two is the way they are numbered. 1st harmonic =100 Hz 1st overtone is 200 Hz.
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Spectrum
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fundamental freq. determines harmonic structure. the harmonics won't have equal amplitudes in various instuments. it's how they get their timbre.
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Development of the Middle Ear
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Middle ear and eustachian tube form a pouch beyond EAM.
Space is filled with mesenchyme (embryo filler/connective tissue) until ossicles develop Total ossification complete 24 wk |
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Anatomy of Middle Ear
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Oval shaped, filled with air, volume 2cc, bound by 6 walls (cube), 3 bones, 2 muscles, 2 nerves, 5 ligaments and Eustachian tube
*cavity is known as tympanic cavity and has "attic" (above ossicles)-can't see w/o catscan -and lower tympanic cavity lined with cilia and mucus. |
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6 walls of middle ear
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Inferior, Superior, Lateral, Medial, Anterior, Posterior
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Floor of Middle Ear
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just below jugular fossa
bulb of jugular *when hearing is checked you hear the jugular pump blood. |
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Ceiling of Middle Ear
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top of the attic is ceiling.
formed by a very thin bone (tegmen tympani) part of the temporal bone. there is a sinus in the bone-atrium, allows air to flow through middle ear to mastoid. |
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Lateral Wall of ME
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formed by tympanic membrane & lined with cilia and mucus
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Medial Wall of ME
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Opposite lateral wall where cochlea is beyond.
The oval window (pressure relief) is the boundary between middle and inner ear. Bulges out to catch waves and stop them in middle ear, but it also helps inner ear. above oval window is facial nerve |
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Anterior Wall of ME
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Made up of a tendon of tensor tympani muscle
Opening of Eustachian tube made up pyramidal eminince (triangular shaped) |
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Posterior Wall of ME
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Opposite Anterior wall, It is a sinus called the aditus.
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Ossicles
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Three bones which bridge the gap between TM and the OW (outer wall)
highly damped-can stop too intense vibrations covered with same mucus that covers middle ear lining Called ossicular chain. |
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Malleus
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largest of three bones
handle is long arm that is deeply embedded in TM & gives concave appearance between head and neck tensor typani muscle is attached can't see above pars tensa handle is called manubrium (arm) |
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Incus
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#2 bone. made up of body, short arm and long arm/crux. You can see behind the TM
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Stapes
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Footplate of stapes is embedded in Oval Window
Space between crura is called obtorator foramen (hole in stirrup) Tendon of stapedius muscle warps around neck of stapes Smallest bone in body |
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2 Nerves of ME
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Chorda Tympani-extension of facial VII
Tympanic Plexus-trigeminal (neither have anything to do with hearing, mostly taste. why ear inf. and taste are affected) |
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2 Muscles of ME
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Tensor Tympani-when tensed the muscle action is to pull malleus medially, tensing TM and damping vibration in ear ossicles. (contracts to dampen noise as we chew)
Stapedius-6mm in length, parallel to facial nerve, when cont. pulls opposite tensor tympani. |
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Muscle Action of ME muscles
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Synergistic-both muscles work together but pull in opposite directions
-Contract causes ossicular chain to stiffen. protects ear from intense sounds. |
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Ligaments
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Superior Malleal ligament
Anterior malleal ligament Lateral malleal ligament Posterior incudal ligament Annular ligament (holds footplate of stapes) *three on malleus, one on incus, ossicular chain in air, so ligaments provide support. |
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Eustachian tube
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Est. communication between middle ear and nasopharynx
35 mm long lined with mucus and cilia upper portion is bone near ME cavity (it's always open) Lower 2/3 cartilaginous (usually collapsed-we can stimulate to open to regulate pressure) |
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Function of Eustachian Tube
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Ventilate ME cavity
Equalize pressure from behind the TM to atmostphere Permits fluid drainage Opening and closing of cartilaginous portion controlled by muscle-tensor palatini |
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Child vs Adult Eustachian Tube
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Until a kid is 6-7 the ET is small and horizontal (no good drain). As kid grows it gets longer and angled.
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Middle Ear Physiology
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It's filled w air and vibrations cause ossicular chain to vibrate. there is a loss of energy as sound changes from air to fluid. middle ear helps to preserve sound wave as it travels to cochlea. called impedence matcher.
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Impedance Matching in ME
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a wave of one property (density and elasticity) won't easily pass to another medium w different properties. middle ear has impediance matching.
Does this how? TM is 17X larger than oval window. Area decreases, pressure increases, lever action of ossicular chain, curved membrane buckling (center TM doesn't move as much) causes increase force in OW |
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No Impedance Matching?
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1/10 of 1% of a sound wave would make it to the cochlea. 99% would be reflected at TM.
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Psycoacoustics - Range of human hearing
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Range of frequencies we hear? 20 Hz -20,000 Hz (hz=1cycle per sec) 1-19 hz called infrasonic. below ability to detect. above 20K is ultrasonic. above ability to detect.
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Human Audibility Curve
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Remember lab. logrhythmic. db vs frequency. low and high sounds need more intensity. Speech sounds 4K most sensitive.
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Duration (psycoacoustics)
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perception of sound begins 10-300 ms. called temporal integration. Easier to pay attention to sounds that have a longer duration.
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Intensity (psycoacoustics)
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When intensity is soft we have to really pay attention. When intensity great it causes pain.
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Threshold
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the lowest and highest percieved sounds.
Clinical threshold-hear 66% 2/3 trials Absolute threshold-50% 1/2 easy to guess. |
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What else effects perception of sound?
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Besides pitch, loudness, frequency, duration
*Localization, Differential sensitivity, pathway (air vs bone), transducer (ear buds) head shadow effect. |
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What is the subjective measure of frequency, intensity?
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Pitch, Loudness (Phon) subjective.
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Role of the Outer Ear
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Conduct sound through the ear canal to the eardrum
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Role of the Middle Ear
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Helps change mediums (air to fluid) so energy is not lost as much.
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Inner Ear
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Fluid filled cochlea converts hydromechanical energy to neural impulses.
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Central Auditory Nervous System
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Auditory nerve, brainstem, brain
Sound transmitted via impulses and analyzed in the brain. 4th part of the ear beyond inner ear. |
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Pathways of Sound
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Air Conduction-outer ear and middle ear, inner ear, much louder
Bone Conduction-inner ear to auditory nerve |
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Types of Hearing Loss
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Conductive-pathological condition on outer or middle ear, sound is attenuated (reduced) because a barrier which results in a loss of hearing
Sensorinerual-path condition affecting the inner ear and sometimes central auditory pathway Mixed-both inner and outer ear Non organic-hearing loss without data to support. faking. |
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Hearing Tests (simple)
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Schwabach-patient to tester
Rinne-air and bone cond Bing-occlude ear during bone cond Weber-measures lateralization, one ear over another. (use tuning fork to scan, not diagnose) |
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Dyne
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Measure of force. Just Barely Audible (JBA) is .0002 d/cm squared.
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Sound Ratios
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2:1 means the sound is 2 times louder than Just Barely Audible. Hearing is log rhythmic
conversation is 2,500:1 (.5 Pa) traffic is 10,000:1 (2Pa) Dynes and Pa are same. Pa is new. 10^0=1, 10^1=10. ratio it is 10 times greater. (goes, 100,1000) |
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Sound Intensity
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We talk about sound in terms of pressure, not power. Pressure is power squared. To determine ratio mult log of ratio by 10
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Inverse Square Law and Intensity
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As distance from source increases, sound energy decreases (sound power is spread out)
intensity of sound decreases proportionatly to the square of the distance from sound source. called inverse square law. =farther you are away from sound the sound is lessened. |
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Results of Inverse Square Law
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intensity is proportional to pressure squared:
10 X log (x/reference)^2 or 20 X log x/reference=dB(SPL) 20 X log 2Pa/.0002Pa) 20 X log (10,000) 20 X 4=80 dB(SPL) |
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Decibel
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Involves a ratio, utilizes a logarithm, is non-linear, reference # specified, relative measure.
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How did Audiology Come About?
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WWII many veterans had hearing problems. Made "aural rehabilitation" program to adjust to civilian life, and program became very successful. Otology is ear doc.
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Audiology Name
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distinct from medicine. Raymond Carhart SLP father of audiology
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What is an Audiologist?
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By virtue of degree licence and training, they are qualified to provide comprehensice services to identify, assess, diagnose, and treat persons with aud imparement and prevent other imparements.
They are autonomous. don't need referral. Similar to SLP certification/licensure. |
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Who has hearing loss?
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50 mil=tinnitus
30 mil=noise 26 mil=hard of hearing 10 mil=permanant noise loss 2 mil=deaf 6/1000 children born with it. 15% kids fail hearing test 90% kids ear inf. by age 6 |
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Audiology Specialties
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Medical, Education, Pediatric, Rehab, Industreal
*school, hospital, private pract. |
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Auditory Mechanism and CNS
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Comprised of nerve VIII and path it takes to primary aud cortex and 2ndary aud cortex in temporal lobe.
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Location of Auditory Canal in Skull
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Near mastoid and styloid process, they are part of bony ear canal. Temporal bone has 3 different densities
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Temporal Bone
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Mastoid is softest part (many air pockets)
Squamus second hardest, then petrous portion (squamous and petrous are similar in density) |
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When do ears develop in fetus?
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from 4-32 weeks. 4-6 weeks of gestation auditory placodes develop. (embryo=ectoderm, mesoderm, endoderm/outer, middle, inner) the otocyst has auditory placodes, which turn into the EAM. 8-28 weeks.
TM develops 35 weeks |
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Why fetal dev. important?
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Because ears develop same time as other organs such as kidneys. If there is a problem, look to syndromes.
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Why is the Auricle/Pinna Shaped the Way it is?
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It directs sounds best into the ear canal. helps localize sound, delivers high frequency.
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Tympanic Membrane
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Divided into pars tensa 90%, pars flaccida 10%. groove at end of ear canal called amulet holds TM
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Fungal Ear Infections:
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White or yellow hue
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Bacterial Ear Infection
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Red or Black hue
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TM perforation
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may result in hearing loss, but will heal and scab over. may have scar tissue. depends on quadrant located.
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