Hearing Smell Taste Lecture- Hearing Flashcards
Soundwaves
Amplitude
- measured as sound pressure
- =loudness
- Height of a wave as measured from the peak to the trough
Sound waves
Frequency
- measured in Hertz (Hz)
- frequency = pitch
- most peoplel detect 20-20,000 Hz
- increases amount of waves per unit time
How does the brain interpret sound?
Mechanical energy of sound waves transducted into neuronal electrical activity
What is sensory transduction?
the conversion of energy from a stimulus into a change in membrane potential
Outer ear
What is the pinna’s function?
The pinna funnels sound waves into the ear canal
How does sound travel from air to ear?
- once the pinna funnels sound waves into the ear canal, sound waves progagate down the canal to the tympanic membrane (aka ear drum)
the tympanic membrane separates the outer ear from the middle ear
middle ear
What happens after sound waves reach the tympanic membrane?
- vibrations in the tympanic membrane cause 3 ossicles (malleus, incus and stapes) to move
middle ear
What are ossicles?
- tiny bones in the middle ear that serve to transmit sounds from air to cochlea
- absence would constitute a moderate to severe hearing loss
middle ear
What do the Tympani and Stapedius muscle do?
- control contact between ossicles to protect from loud sounds
- also mute self-made sounds (ex. swallow)
middle ear
Where is the stapedius muscle located?
- Stapedius muscle is caudal/inferior to the stapes bone
inner ear
What does the stapes contact? What is the function of this?
- stapes contacts the oval window
- the oval window transfers vibrations to 3 fluid filled canals in cochlea
inner ear
What does the cochlea look like?
small and coiled
inner ear
What separates the cochlea’s canals?
the basilar membrane
inner ear
Basilar membrane function
- Vibrates- Different areas are sensitive to specific frequencies
- high freq at narrow stiff base (when cochlea unrolled)
- low freq at wide, floppy apex (when cochlea unrolled)
What is a tonotopic map?
an ordered map of frequencies created by the responding of neurons within structures in the auditory system