(1) Ear Design
• Ear is like a well designed funnel.
• Sound waves spiral down into auditory canal.
• Sound Waves smack against ear drum (tympanic membrane).
(2) Vibrations
• Sound Waves Tympanic Membrane– Eardrum literally like the leather on a drum
• T-Membrane Hammer Anvil Stirrup– Hammer, Anvil and Stirrup are very small bones
in inner ear
• Stirrup Oval Window Inner Ear Fluid
(3) Cochlea
• Cochlea = Snail like structure in inner Ear.
• Contains Organ of Corti:– Contains hearing receptors / hair cells– Hair cells stimulated by movement of Inner Ear Fluid
• Basilar Membrane– Type of membrane on specific receptors– Responds to changes in pitch
• Fluid Receptors Cochlear Nerve Brain
(4) Equilibrium & Balance
• Your ears keep track of your body’s position.
• Equilibrium receptors lie within the inner ear of your ears (Vestibular Apparati).
• 2 Types of Equilibrium:– Static– Dynamic
(5) Static Equilibrium
• Head Balance
• Static Receptors = Maculae:– On top of maculae lies the otolithic membrane
(gel-like)– Head Moves Otoliths Moves!– Movement of Otolithic Receptor Impulse to
Vestibular Nerve & Brain
• Tells your brain when your head is not upright.
(6) Dynamic Equilibrium
• Rotation & Angles of Head
• Semicircular Canals of Cochlea:– Contain receptors = Crista Ampullari– Crista Ampullari contain receptor hairs,
endolymph fluid and a capula cap– Body Movement endolymph movement
Push on Capula Cap Receptor Hairs Vestibular Nerve & Brain
(7) Motion Sickness
• Inefficient dynamic equilibrium…– Semicircular Canals either too sensitive or too
slow at sending messages
• Too many visual messages
• Too many inner ear messages
• Visual conflicts with Inner Ear
• Unique to each individual
(9) Conduction Deafness
• Something Blocks Tympanic Membrane
• Sound Waves cannot reach Ear Drum + Inner Ear
• Causes:– Ear Wax– Ruptured Ear Drum– Injured Hammer, Anvil and/or Stirrup
• Usually Temporary, Solved by Surgery
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