The physics of the ear

The physics of the ear

• Comps II Presentation

• Jed Whittaker

• December 5, 2006

I. Ear anatomy

• I. Ear anatomy

• II. Outer ear resonator

• III. Middle ear impedance matching

• IV. Inner ear

• a. Anatomy

• b. Theories of cochlear function

• c. Traveling wave theory

• VII. Current work

• a. Physical model

• b. Mathematical model

I. Ear anatomy

• I. Ear anatomy

• II. Outer ear resonator

• III. Middle ear impedance matching

• IV. Inner ear

• a. Anatomy

• b. Theories of cochlear function

• c. Traveling wave theory

• VII. Current work

• a. Physical model

• b. Mathematical model

Ear anatomy

Ear anatomy

Ear anatomy

Ear anatomy substructures

I. Ear anatomy

• I. Ear anatomy

• II. Outer ear resonator

• III. Middle ear impedance matching

• IV. Inner ear

• a. Anatomy

• b. Theories of cochlear function

• c. Traveling wave theory

• VII. Current work

• a. Physical model

• b. Mathematical model

The outer ear

Partially closed pipe resonator model

Outer ear resonator

I. Ear anatomy

• I. Ear anatomy

• II. Outer ear resonator

• III. Middle ear impedance matching

• IV. Inner ear

• a. Anatomy

• b. Theories of cochlear function

• c. Traveling wave theory

• VII. Current work

• a. Physical model

• b. Mathematical model

The middle ear

Transmission and reflection

Power transmission

Ossicles as levers

Stapes footprint

Impedance match

I. Ear anatomy

• I. Ear anatomy

• II. Outer ear resonator

• III. Middle ear impedance matching

• IV. Inner ear

• a. Anatomy

• b. Theories of cochlear function

• c. Traveling wave theory

• VII. Current work

• a. Physical model

• b. Mathematical model

The inner ear

Cochlear schematic

Cochlear cross-section

Hair cell shearing

I. Ear anatomy

• I. Ear anatomy

• II. Outer ear resonator

• III. Middle ear impedance matching

• IV. Inner ear

• a. Anatomy

• b. Theories of cochlear function

• c. Traveling wave theory

• VII. Current work

• a. Physical model

• b. Mathematical model

Helmholtz’s resonance theory (1857)

Problems with resonance theory

Competing theories

• Telephone theory required each hair cell to reproduce all frequencies

• Standing wave theory had hair cells detecting patterns on the basilar membrane

• Traveling wave theory described hair cells as detecting the amplitude of a wave traveling along the basilar membrane

I. Ear anatomy

• I. Ear anatomy

• II. Outer ear resonator

• III. Middle ear impedance matching

• IV. Inner ear

• a. Anatomy

• b. Theories of cochlear function

• c. Traveling wave theory

• VII. Current work

• a. Physical model

• b. Mathematical model

I. Ear anatomy

• I. Ear anatomy

• II. Outer ear resonator

• III. Middle ear impedance matching

• IV. Inner ear

• a. Anatomy

• b. Theories of cochlear function

• c. Traveling wave theory

• VII. Current work

• a. Physical model

• b. Mathematical model

I. Ear anatomy

• I. Ear anatomy

• II. Outer ear resonator

• III. Middle ear impedance matching

• IV. Inner ear

• a. Anatomy

• b. Theories of cochlear function

• c. Traveling wave theory

• VII. Current work

• a. Physical model

• b. Mathematical model

Appendix A

• Transmission

Transmission and reflection

Transmission and reflection

Power

Power transmission coefficient

Power transmission

Appendix B

• Spiral cochlea

Appendix C

• Traveling wave derivation