The Ear Flashcards
(17 cards)
Functions of the ear
1
Hearing
-detection of vibrations , there frequency and amplitude
Functions of the ear
2
Balance
-detection of direction of motion, acceleration and head position related to gravity
Structure of the ear
Outer ear
Filled with air
Structure of the ear Outer
Middle ear
Filled with air
Structure of the ear
Inner ear
Filled with lymph
Pinna ( outer ear )
Function - collects sound waves and passes them into the auditory canal
Auditory canal
Function - carried the sound waves to the eardrum
-wax is secreted outside the eardrum to trap dust particles and protect the ear
Eardrum
-small tightly stretched membrane
-seperates the outer ear from the middle ear
-vibrates due to the air vibrations that reach it
Ossicles (bones)
Function - transmit vibrations from the outer to the inner ear +amplify the vibrations
Bones- hammer ,anvil and stirrup
Eustachian tube
Function- equalises pressure on both sides of the eardrum
-connects the middle ear to the pharynx
Cochlea (spiral tube)
-function - hearing
-contains sound receptors that convert sound waves into nerve impulses
Auditory nerve/cochlear nerve
-function - carries impulses from the cochlea to the cerebellum of the brain
Semi - circular canals
-function- controls balance
-there are three to control balance in three dimensions
Vestibular nerve
Function- carried impulses from the balance structures to the cerebellum of the brain
How do we hear
-sound is caused by vibrations in the air
-vibrations collected by outer ear, pass thru the middle ear where the vibrations are changed to electrical impulses and sent to the brain , which interprets them as sound
-cochlea contains receptors
Hearing disorder
Glue ear
Cause- infection or blocked Eustachian tube
Symptoms- reduced hearing
Treatment - grommets
Grommets
Tiny ventilation tubes inserted into the ear, they allow air in which builds up and forces the fluid down the Eustachian tube
The tube fall out naturally
