2-hearing Flashcards
parts of the outer ear
- Pinna—visible part that protrudes from our heads
- Auditory canal
- Tympanic membrane (eardrum)
parts of the middle ear
- ossicles—three tiny bones
- malleus (hammer)
- Incus (anvil)
- Stapes (stirrup)
parts of the inner ear
- Semi-circular canals
- Cochlea
- basilar membrane
Semi-circular canals
—involved in valance and movement (vestibular sense)
cochlea
fluid-filled, snail-shaped structure that contains the sensory receptor cells (hair cells) of auditory system
where are hairs in the ear located?
embedded in basilar membrane—thin strip of tissue within the cochlea
medial geniculate body
back of thalamus, picks up that we’re getting signals from ear, sends it off to the primary auditory cortex
process of hearing! :O
- sound waves travel along auditory canal and strike the tympanic membrane, causing it to vibrate
- Results in movement of there three ossicles
- As the ossicles move, stapes presses into a thin membrane of the cochlea known as the oval window
- Fluid inside the cochlea begins to move, which stimulates hair cells
- Auditory info is sent to inferior follicular—medial geniculate nucleus of the thalamus and then to the auditory cortex
- There is evidence that info about auditory recognition and localization is processed in parallel streams
the temporal theory of hearing
frequency is coded by the activity level of a sensory neuron – Given hair cell would fire action potentials related to the frequency of the sound wave
- physical limitations—a neuron can only fire soooo many times a second
place theory
different portions of the basilar membrane are sensitive to sounds of different frequencies
when are the systems of hearing used?
both systems are used to perceive pitch!!
up to 4000Hz, we use both systems
sounds > 4000Hz, rely on place
Monoaural cue
Helpful in locating above or Below and in front of behind us
- differences in timing and levels
- relies on pinna—interacts with sounds that is coming to our ears
Binaural cues
provide information on the location along a horizontal axis by relying on differences in Patterns of vibration of the eardrum between our two ears
Interaural level differences
- Sound from one side is more intense in one ear than the other
- Attenuation of sound wave as passes through time
Interaural timing differences
Small difference in time at which a given sound wave arrives at each ear
