Special Senses: The Ear
Functions of the Ear Hearing Equilibrium (Balance)
External Ear Anatomy Involved in hearing only Pinna – traps sound Ear canal Lined with skin Ceruminous glands Tympanic Membrane
Middle Ear Anatomy Tympanic cavity Eustachian tube Ossicles Malleus (hammer) Incus (anvil) Stapes (stirrup)
Inner Ear Anatomy Organs for hearing and balance Filled with perilymph Cochlea Vestibule Semicircular canals
Inside the Cochlea Oval window Organ of Corti Round window Endolymph Hair cells Membranes Cochlear nerve Round window
Hearing Pinna collects sound Sound waves vibrate tympanic membrane (eardrum) Eardrum movement is transferred to ossicles Ossicles vibrate oval window of cochlea
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
Hearing Action potential travel through auditory nerve to brain! You hear something!
Hearing
Hearing
Hearing Damage Tinnitus Deafness
Cochlear Implants
Balance In the vestibule: Senses head movement Endolymph Hair cells Otoliths Senses head movement
Balance and Motion In semicircular canals: Senses acceleration Endolymph Hair cells Cupula Senses acceleration