Hearing
- Amplitudes: determines the loudness, higher amplitude = higher sound wave
- Wavelengths: determines the pitch, wavelengths of higher frequency = higher pitch
- Timbre: the quality of a sound; differentiates varied musical instruments/voices
- Sound localization: the process to determine the location of a sound; difference between sound received by two ears
Pitch perception
- Place theory: different positions on the basilar membrane respond to different frequencies (works well for high-pitched sounds)
- Frequency theory: high/low sound frequencies transform to high/low rate of neural impulses (works well for low-pitched sounds)
- Volley theory: refines the frequency theory; groups of neurons produce a stream of nerve impulses more rapid than the max firing rate of any single one, like volleys of arrows
Hearing loss
- Conduction deafness: loss of hearing that results when the eardrum is punctured or any of the ossicles lose their ability to vibrate. A hearing aid may restore hearing.
- Sensorineural deafness: loss of hearing that results from damage to the cochlea, hair cells, or auditory neurons. Cochlear implants may restore some hearing.
Ear structure (Optional)
- Outer ear: pinna, auditory canal, eardrum
- Middle ear: hammer, anvil, stirrup (three tiny bones)
- Inner ear: cochlea, semicircular canals, vestibular sacs
- Cochlea: snail-shaped fluid-filled tube that transduces (from movement of hair cell on the basilar membrane to impulses in nearby nerves)
- Auditory nerve: axons of neurons in the cochlea carry messages to the auditory cortex of the temporal lobes