The Auditory System: Hearing Flashcards
Give a brief description of sound waves.
Sound waves are vibrations of molecules, which means that they must travel through some physical medium, such as air. Like light waves, sound waves are characterized by their wavelength, their amplitude, and their purity. These physical properties affect mainly the perceived (psychological) qualities of pitch, loudness, and timbre, respectively. However, they interact in complex ways to produce perceptions of these sound qualities.
Each part of the ear conducts sound differently, explain this.
The external ear depends on the vibration of air molecules. The middle ear depends on the vibration of movable bones. And the inner ear depends on waves in a fluid, which are finally converted into a stream of neural signals sent to the brain
Describe sound collection at the external ear.
The external ear consists mainly of the pinna, a sound-collecting cone. When you cup your hand behind your ear to try to hear better, you are augmenting that cone. Sound waves collected by the pinna are funneled along the auditory canal toward the eardrum, a taut membrane that vibrates in response.
How is sound conducted in the middle ear?
In the middle ear, the vibrations of the eardrum are transmitted inward by a mechanical chain made up of the three tiniest bones in your body (the hammer, anvil, and stirrup), known collectively as the ossicles. The ossicles form a three-stage lever system that converts relatively large movements with little force into smaller motions with greater force. The ossicles serve to amplify tiny changes in air pressure.
Describe sound conduction in the inner ear
The inner ear consists largely of the cochlea, a fluid-filled, coiled tunnel that contains the receptors for hearing. The ear’s neural tissue, which is functionally similar to the retina in the eye, lies within the cochlea on the basilar membrane. The basilar membrane, which runs the length of the spiraled cochlea, holds the auditory receptors, called hair cells. Waves in the fluid of the inner ear stimulate the hair cells. Like the rods and cones in the eye, the hair cells convert this physical stimulation into neural impulses that are sent to the brain
Give an overview of how sound conduction.
Converting sound pressure to information processed by the nervous system involves a complex relay of stimuli. Waves of air pressure create vibrations in the eardrum, which in turn cause oscillations in the tiny bones inthe inner ear (the hammer,anvil, and stirrup). As they are relayed from one bone to the next, the oscillations are magnified and then transformed into pressure waves moving through a liquid medium in the cochlea. These waves cause the basilar membrane to oscillate, stimulating the hair cells that are the actual auditory receptors
What is place theory?
Place theory holds that perception of pitch
corresponds to the vibration of different portions, or places, along the basilar membrane.
What is frequency theory?
Frequency theory holds that perception of pitch corresponds to the rate, or frequency, at which the entire basilar membrane vibrates.
What is audiotry localization?
auditory localization—locating the source of a sound in space.
