Sound and Hearing Flashcards
(20 cards)
what is sound?
- sound is produced when matter is acted upon
- vibration that propagates as an acoustic wave
- made up of amplitude (loudness) and frequency (pitch)
what is amplitude?
- sound pressure level
- magnitude of sound (loudness)
- measured in decibels
what is frequency?
- measured in hertz
- pitch is the frequency of waves in a given amount of time
- high pitch = high frequency
what is the process of hearing (outer ear)?
AIR -> To Pinna -> to external auditory canal to Tympanic membrane (causing it vibrate)
what is the process of hearing (middle ear)?
Ossicles (small bones) vibrate and their vibration acts to amplify the sound waves these are passed through stapes to oval window of cochlear
what is the process of hearing (inner ear)?
Stapes footplate rocks in and out of cochlear and generates waves in the perilymph of the scala vestibuli. These travel up the cochlear duct. The waves cause waves in the scala media which has the organ of corti on it and hair cells in it – this is how these are stimulated
what structures are located in the outer ear?
- pinna
- external auditory meatus
- tympatic membrane
what structures are located in the middle ear?
- ossicles
- ligaments and muscles
what structures are located in the inner ear?
- cochla
- auditory nerve
what is the function of the external auditory meatus?
- resonator that amplifies certain pitches or frequencies of sound before they reach the TM
- its a small opening surrounded by cartilage
what is the function of the tympatic membrane?
- sound energy hits the TM and causes it to vibrate
- cone of light thats a boundary between outer and middle ear
what is the function of the ossicles?
- to amplify the sound energy applied to TM to the fluid in the cochlea
- inclued the malleus, incus and stapes (MIS)
what is the auditory tube?
- 3.8cm tube runs from middle ear to nasopharynx
- opens occasionally to equalize the pressure in the middle ear
what is the function of the bony labrynth?
- oval window (footbed of the stapes that moves fluid called perilymph)
- round window (perilymph exerts force on the round window causing it to bulge slightly
what is the cochlea?
- filled with perilymph
- movement of perilymph leads to movement of basilar membrane
- movement of basilar membrane means hair cells bend which cause the action potential to be sent along the cochlea nerve
what is auditory perception?
- ability to receive, identify and attach meaning to sounds
what is conduction deafness?
- hampers sound conduction to the fluids of the inner ear
- e.g impacted earwax
what is sensorineural deafness?
- damage to the neural structures at any point from the cochlear hair cells to auditory cortical cells
what is tinnitus?
- Ringing or clicking sound in the ears in the absence of auditory
stimuli – is disorder of the cochlear
what is menieres syndrome?
- Entire labyrinth disorder (affects the cochlea and the semicircular
canals) causing vertigo, nausea, and vomiting
