Chapter 9 Flashcards
Cycle
In a sound wave, a repeating segment of air pressure
Sound waves
Waves of pressure changes in air caused by the vibrations of a source
Periodic sound waves
Waves in which the cycles of compression and rarefaction repeat in a regular, or periodic, fashion
Pure tone
A sound wave in which air pressure changes over time according to w mathematical formula called sine wave or sinusoid
Frequency
The physical dimensions of sound that is related to the perceptual dimension of pitch; expressed in hertz, the number of cycles per second of. Periodic sound wave
Pitch
The perceptual dimension of sound that corresponds to the physical dimension of frequency; the perceived highness or lowness of a sound
Hertz(Hz)
The number of cycles per second of a sound wave; the physical unit used to measure frequency
Amplitude
The difference between the maximum and minimum sound pressure in a sound wave; the physical dimension of sound that is related to the perceptual dimension of loudness
Loudness
The perceptual dimension of sound that is related to the physical dimension of amplitude; how intense or quiet a sound seems
Decibels
A physical unit used to measure sound amplitude; logarithmically related to sound pressure measured in micropascals
Audibility curve
A curve showing the minimum amplitude at which sounds can be detected at each frequency
Equal loudness contour
A curve showing the amplitude of tones at different frequencies that sound about equally loud
Fourier analysis
A mathematical procedure for decomposing a complex waveform into a collection of sine waves with various frequencies and amplitudes
Fourier spectrum
A depiction of the amplitudes at all frequencies that make up a complex wave form
Fundamental frequency
The frequency of the lowest-frequency component of a complex waveform;determines the perceived pitch of the sound
Harmonic
A component frequency of a complex waveform that is an integer mult
E of the fundamental frequency
Timbre
The difference in sound quality between two sounds with the same pitch and loudness
Pinna
Outermost portion of the ear
Auditory canal
A narrow channel that funnels sound waves gathered by the pinna onto the tympanic membrane and that amplifies certain frequencies in those waves
Tympanic membrane
A thin, elastic diaphragm at the inner end of the auditory canal that vibrates in response to the sound waves that strike it.
Ossicles
Three small bones in the middle ear that transmit sound energy from the tympanic membrane to the inner ear
Malleus
A small bone in the inner ear; one of the ossicles, transmits sound energy from the tympanic membrane to the incus
Incus
A small bone in the inner ear; one of the ossicles; transmits sound energy from the malleus to the stapes
Stapes
A small bone in the inner ear; one of the ossicles; transmits sound energy from the Indus to the oval window
Oval window
A membrane covered opening at the base of the cochlea; vibrations of the membrane transmit sound energy from the ossicles into the cochlea
Eustachian tube
A tube connecting the middle ear and the top part of the throat; normally closed but can be briefly opened to equalize the air pressure in the middle ear with the air pressure outside
Cochlea
A coiled, tapered tube within the temporal bone of the head. Partitioned along its length into three chambers; contains the structures involved in auditory transduction
Vestibular canal
One of the three chambers in the cochlea, separated from the cochlear duct by Reissner’s membrane; filled with perilymph
Cochlear duct
One of the three chambers in the cochlea; separated from the tympanic canal by the basilar membrane, contains the organ of corti, filled with endolymph
Tympanic canal
One of the three chambers in the cochlea; separated from the cochlea duct by the basilar membrane; filled with perilymph
Helicotrema
An opening in the partitioning membranes at the apex of the cochlea. Provides an open pathway for the perilymph to carry vibrations through the cochlea
Round window
A membrane-covered opening at the base of the tympanic canal in the cochlea, serves as a kind of relief valve for the pressure waves traveling through perilymph
Basilar membrane
A tapered membrane suspended between the walls of the cochlea; thicker, narrower, and stiffer at the base than at the apex
Characteristic frequency
The frequency to which each location on the basilar membrane responds to most readily
Organ of corti
A structure in the cochlea situated on the basilar membrane, consists of three critical components-inner hair cells, outer hair cells, and the tectorial membrane
Inner hair cells
Neurons in the organ of Corti; serve to amplify and sharpen the responses of inner hair cells
Outer hair cells
Neurons in the organ of corti; serve to amplify and sharpen the responses of inner hair cells
Tectorial membrane
A membrane that lies above the hair cells in the organ of Corti
Stereocilia
Small hairlike projections on the tops of inner and outer hair cells
Auditory nerve
The nerve that conveys signals from the hair cells in the organ of Corti to the brain, made up of Type 1 and Type 2 auditory nerve fibers bundled together
Tip links
Tiny fibers connecting the tips of adjacent stereocilia on hair cells; increased tension on tip links pulls open ion channels in the membranes of the stereocilia
Motile response
A response by outer hair cells that magnifies the movements of the basilar membrane, amplifying sounds and sharpening the response to particular frequencies
Place code
Frequency representation based on the displacement of the basilar membrane at different locations
Temporal code
Frequency representation based on a match between the frequencies in incoming sound waves and the firing rates of auditory nerve fibers
Hearing impairment
A decrease in a persons ability to detect or discriminate sounds, compared to the ability of a healthy young adult
Tinnitus
A persistent perception of sound, such as a ringing or buzzing, not caused by any actual sound.
Audiometer
An instrument that presents pure tones with known frequency and amplitude to the right or the left ear; used in estimating the listeners absolute threshold for specific frequencies and to construct an audiogram
Audiogram
A graphical depiction of auditory sensitivity to specific frequencies, compared to the sensitivity of a standard listener; used to characterize possible hearing loss
Conductive hearing impairments
Hearing impairments characterized by a loss of sound conduction to the cochlea, as a result of problems in the outer or middle ear
Sensorineural hearing impairments
Hearing impairments caused by damage to the cochlea, the auditory nerve, or the auditory areas or pathways of the brain.
