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Middle Ear. Acoustic energy. 99.9%. Net loss = 40-55 dB. P 1. P 2. A 1. A 2. Impedance Matching. TM >>> Oval window. Areal Ratio F=P 1 A 1 =P 2 A 2 therefore P 2 /P 1 =A 1 /A 2. P 1. P 2. A 1. A 2. L 1. L 2. Impedance Matching.
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Acoustic energy 99.9% Net loss = 40-55 dB
P1 P2 A1 A2 Impedance Matching TM>>>Ovalwindow • Areal RatioF=P1A1=P2A2 therefore P2/P1=A1/A2
P1 P2 A1 A2 L1 L2 Impedance Matching • Areal RatioF=P1A1=P2A2 therefore P2/P1=A1/A2 Malleus>Incus • Lever RatioL1/F1=F2/L2
P1 P2 A1 A2 L1 L2 Impedance Matching • Areal RatioF=P1A1=P2A2 therefore P2/P1=A1/A2 • BucklingAction • Lever RatioL1/F1=F2/L2
Acoustic Impedance Resonance frequencyaffects intensity during sound transmission
Acoustic Impedance Also criticial in the cochlea STIFFNESS LimitsLow frequency LimitsHigh frequency MASS
Transfer Functions Volume of middle ear space Mass of ossicles