1. Special Senses: The Ear

2. Functions of the Ear
Hearing
Equilibrium (Balance)

3. External Ear Anatomy Involved in hearing only Pinna – traps sound
Ear canal
Lined with skin
Ceruminous glands
Tympanic Membrane

4. Middle Ear Anatomy Tympanic cavity Eustachian tube Ossicles
Malleus (hammer)
Incus (anvil)
Stapes (stirrup)

5. Inner Ear Anatomy Organs for hearing and balance Filled with perilymph
Cochlea
Vestibule
Semicircular canals

6. Inside the Cochlea Oval window Organ of Corti Round window Endolymph
Hair cells
Membranes
Cochlear nerve
Round window

7. Hearing Pinna collects sound
Sound waves vibrate tympanic membrane (eardrum)
Eardrum movement is transferred to ossicles
Ossicles vibrate oval window of cochlea

8. Hearing Stapes vibrates the oval window.
Movement of oval window moves fluid in cochlea.
Fluid movement vibrates membranes in Organ of Corti
Membrane movement bends hairs
Bent hairs cause action potential

9. Hearing Action potential travel through auditory nerve to brain!
You hear something!

10. Hearing

11. Hearing

12. Hearing Damage
Tinnitus
Deafness

13. Cochlear Implants

14. Balance In the vestibule: Senses head movement Endolymph Hair cells
Otoliths
Senses head movement

15. Balance and Motion In semicircular canals: Senses acceleration
Endolymph
Hair cells
Cupula
Senses acceleration