Nonvisual Senses- Hearing
Terms
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- diffrences in hearing between the sexes
- women have better hearing sensitivity and experiance greater deterioration from high noise exposure. Men are better at sound localization and detecting specific sounds
- how is sound produced?
- sound requires a medium to travel through such as water and air. Sound vibrations create constant sucessive bunching and spreading of molecules.
- the outer ear
- the pinna
- tympanic membrane
- sound waves pass through the canal to this area better known as the ear drum. Sound waves make the drum vibrate
- Middle ear
- the vibrations of the eardrum are convayed to the bones (ossicles) of the middle ear
- Ossicles
- three tiny bones called the malleus(hammer), the incus (anvil), and the (stapes) stirrup
- eustachain tubes
- connect ear to throut which permits ear to equalize air pressure
- Cochlea
- the oval window in the inner ear. Vibrations in the window send waves through a fluid filled membrane
- basilar membrane
- found in the cochlea the movement of hair cells known as cillia triggers inpulses that travel along the auditory nerve
- pitch
- the frequency of a sound
- absolute pitch
- identify and produce tones of a specific pitch
- hearing range
- 20-20000 Hz
- place theory
- assumes that particular points on the basilar membrane vibrate maximally in response to sound waves of particularly frequencies
- Bekesy
- won the nobel prize for his reaserch on the place theory
- frequency theory
- assumes that the basilar membrane vibrates as a whole in direct proportion to the frequency of the sound waves striking the ear drum (only holds true for sounds over 1000 Hz)
- volley theory
- weaver, between 1000 and 5000, sound waves in this range induce certain groups of auditory neurons to fire in volleys
- loudness perception
- depends on both the number and the firing thresholds of hair cells on the basilar membrane that are stimulated
- unit of intensity
- decible named for Alexander Gram Bell
- conduction deafness
- a mechanical problem in teh outer or middle ear, can be simply wax, if more serious sugury can help
- nerve deafness
- a problem with the inner ear, the auditory nerve, or the auditory cotex. typically results in loss of frequency
- cochlear implants
- rlectronic stimulation of the neurons
- timbre
- the quality of a sound
- sound localization
- involves discerning where sounds are coming from, important for servival