physiology of hearing and balance Flashcards
what does the external ear do?
collect sound waves
what does the middle ear do?
amplify sound waves
what does the inner ear do?
sound transducer and maintains balance
why is eustachian tube important?
ventilates middle ear and maintains equal air pressure across tympanic membrane
where are the ossicles?
middle ear
cochlea is for?
hearing
vestibule is for?
balance
what does the auricle do?
catches sound waves
where does the auricle send the sound waves?
deeper into the ear through the external acoustic meatus
what happens when sound waves reach the end of the external acoustic meatus?
they push the ear drum back and forth and make it vibrate. the vibrations are then passed onto the ossicles
what do the ossicles do?
they amplify the sound to make it stronger as they move into the fluid filled cochlea. they transmit the sound waves from the tympanic membrane to the cochlea
3 chambers in cochlea?
scala vestibuli
scala media
scala tympani
what is the important membrane in the cochlea?
basilar membrane
what happens in the basilar membrane?
the hairs in the membrane detect vibrations and transduce these into nerve impulses which pass to organ of corti.
what sounds are heard in the short stiff hairs at start of membarne?
high frequency sounds
what sounds are heard in the long wiggly hairs at start of membarne?
low frequency sounds
what happens in the organ of corti?
action potentials eventually sent through cochlear nerve, auditory pathwya to cerebral cortex
what is frequency?
number of waves that pass a certain point in a given time frame
what makes a high pitched noise?
faster numerous waves
what makes a low pitched noise?
slower and less waves
what does loudness depend on ?
amplitude
what is amplitude?
difference between the high and low pressure created in the air by that sound wave
what does the vestibular apparatus control?
balance
fluid in the vestibular apparatus is controlled by what?
head movement
how is balance controlled?
when your head moves in a certain way, the fluid in the semicircular canals will move in a certain way and stimulate hair cells which send action potential to the brain
