Ear Today Gone Tomorrow

Main Components of the Hearing Mechanism Outer Ear Middle Ear Inner Ear Central Auditory Nervous System

Structures of the Outer Ear Auricle (Pinna) Collects sound Helps in sound localization Directs sounds to the eardrum

Tympanic Membrane “eardrum” Forms boundary between outer and middle ear Vibrates in response to sound

The Ossicular Chain A: Malleus (Hammer) B: Incus (Anvil) C: Stapes (Stirrup) Ossicles are smallest bones in the body Vibrates when eardrum vibrates

Eustachian Tube connects middle ear to back of the throat Equalizes air pressure Normally closed except during yawning or swallowing Not a part of the hearing process

Structures of the Inner Ear Cochlea - Snail-shaped organ with a series of fluid-filled tunnels; converts mechanical energy into electrical energy

Vestibular System Consists of three semi-circular canals Shares fluid with the cochlea Controls balance No part in hearing process

Hair Cells Frequency-specific High pitch sounds = base of cochlea Low pitch sounds = apex of cochlea

Sound enters the ear and strikes the eardrum causing it to vibrate The vibration is passed to the three middle ear bones (hammer, anvil, stirrup) Vibrations create waves in the fluid found in the cochlea of the inner ear. Small hairs within the cochlea are bent sending an impulse to the auditory nerve The auditory nerve sends information to the brain

Deafness failure of the three tiny bones to vibrate The two main types of deafness Conductive deafness failure of the three tiny bones to vibrate failure of the eardrum to vibrate Nerve deafness caused by disease, trauma electrical impulses aren't able to reach the brain

Hearing Aids The microphone picks up sounds from the environment and sends them to a processor that amplifies the signal (makes it louder) After the sound is amplified, the receiver directs sound into the ear canal.