The Ear Histology doesn’t get better than this!

Anatomy of the Ear

Middle Ear

The Inner Ear Osseous Labyrinth

Bony Labyrinth Membranous Labyrinth The Inner Ear

Membranous in Osseous Labyrinth

Receptor Organs (red) in the Membranous Labyrinth

General Structure of a Receptor Organ

“Hairs” of a Hair Cell

A Macula

~ 10 microns ~ 1 centimeter

Crista Ampulla Cupula

Bone 2Osseous labyrinth 3Membranous labyrinth The cochlear duct is a long coiled tube in a long coiled hole in the bone. The organ of Corti is a long coiled ribbon Uncoiled

Membranous Labyrinth in Osseous Labyrinth

The Cochlea is coiled

The organ of Corti

The Organ of Corti is a Ribbon

Base | | Tip High Pitch Low Pitch High pitch is detected at the base of the cochlea because the basilar membrane is narrower there. Each sound frequency is detected at a specific position along the cochlea at which it resonates. Basilar membrane

Pathway of Sound through the Ear

Movement of Fluid in the Cochlea

Movements of the basilar membrane from sound

Base | | Tip High Pitch Low Pitch Basilar membrane

Swings with Different Lengths of Rope Will Vibrate At Different Frequencies…

The Organ of Corti

Two ways to make a swing go higher Pushing Pumping

The Extraordinary Outer Hair Cell

Ears make sound called otoacoustic emissions

Mechanical Receptors of the Hair Cell

Pathologies of Ears 1. Deafness 2. Vertigo 3. Tinnitus