Ear Flashcards
(20 cards)
Main areas of the ear
Outer ear
Middle ear
Inner ear
Central auditory nervous system
Structures of outer ear
Auricle (pinna)
Collects sound
Helps in sound localization
Auditory canal
Tube inside cranium
Directs sound to eardrum
Tympanic membrane
“Eardrum”
Boundary between outer and middle ear
Vibrates in response to sound waves
Ossicular chain
3 smallest bones in body, carries vibrations from eardrum for cochlea
1 malleus
Hammer
2 incus
Anvil
3 strapes
Stirrup
Semicircular canals
Three semicircular canals make up vestibular system
Not part of hearing
Controls balance
Shared fluid with cochlea
Inner ear- Cochlea
Snail shaped organ with a series of fluid-filled tunnels
Converts mechanical energy into electrical energy
Cochlear hair cells- hair cells inside cochlea
Bend as fluid vibrates
Bending hair cells send electrical impulse to auditory nerve
Eustachian tube
Not part of hearing process
Equalizes air pressure
Normally closed except during yawning or swallowing
Eustachian tube Connects middle ear to
Back of throat
Step 1 of hearing
Sound enters the ear and strikes the eardrum causing it to vibrate
Step 2
The vibration is passed to the three middle ear bones (hammer, anvil, stirrup)
Step 3
Vibrations create waves in the fluid in the cochlea of the inner ear. Hair cells are bent sending an impulse to the auditory nerve
Step 4
The auditory nerve sends information to the brain
Conductive deafness
Failure of the eardrum to vibrate in response to sound waves
* Failure of the three tiny bones inside the middle ear to pass along
sound waves to the inner ear
Nerve (sensorineural) deafness
Caused by disease, trauma or some other disruptive event targeting the cochlear nerve
* 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.
