hearing and equilibrium Flashcards
what is the function of the ears?
hearing and equilibrium
what are the mechanoreceptors and where are they located?
they are the hair cells and are located in fluid-filled membranous/ labyrinth
what is the fluid in the membranous?
endolymph- surrounds hair cell
perilymph- circulates around labyrinth
what does the outer ear consist of?
auricle
auditory canal
tympanic membrane
what does the middle ear consist of?
tympanic cavity
auditory ossicles- malleus, incus, stepes
pharyntympanic or auditory tube
what is the auditory tube?
it connects the middle ear to the nasopharynx
What does the inner ear consist of?
fluid-filled bony labyrinth lined in the membrane - membranous labyrinth
cochlea, vestibule, semicircular canals
what is sound?
air pressure waves
wavelength (distance between waves) pitch of sound
amplitude(height) is the loudness
what is frequency?
measured in hz = waves/msec
increased frequency= higher pitch
hertz
what is amplitude?
wave height measured in decibals dB
increased amplitude=louder
what are the mechanoreceptors?
located in spiral organs (organ of corti) of cochlea
receptors called hair cells
what happens when stereocilia on cells bend?
mechanically gated ion channels open and an action potencial occurs
explain how the ion channels open for an action potencial to occur?
bending of the stereocillia causes mechanically gated k channels to open, k concentration is high in endolymph so k flows in and depolarization occurs
what are the steps in hearing?
- sound waves cause tympanic m to vibrate
- ossciles amplify vibrations
- stapes pushes against oval window creating waves in perilymph
- pressure waves in tympanic duct moves bassilar m.
- cilia of hair cells in cochlear duct bend as they touch tectorial membrane causing depolarization
- wave energy dsicepated at round window
what does the flexibility of the basilar membrane varies in length causes what?
causes different hair cells to respond to sounds of different pitch