chapter 9 (M. Wolfe) Flashcards
acoustic reflex
A reflex that protects the ear from intense sounds, via contraction of the stapedius and tensor tympani muscles.
afferent fiber
A neuron that carries sensory information to the central nervous system.
amplitude or intensity
The magnitude of displacement (increase or decrease) of a sound pressure wave. Amplitude is perceived as loudness.
audibility threshold
The lowest sound pressure level that can be reliably detected at a given frequency.
auditory nerve
A collection of neurons that convey information from hair cells in the cochlea to (afferent) and from (efferent) the brain stem.
characteristic frequency (CF)
The frequency to which a particular auditory nerve fiber is most sensitive.
cochlea
A spiral structure of the inner ear containing the organ of Corti.
cochlear nucleus
The first brain stem nucleus at which afferent auditory nerve fibers synapse.
efferent fiber
A neuron that carries information from the central nervous system to the periphery.
equal-loudness curve
A graph plotting sound pressure level (dB SPL) against the frequency for which a listener perceives constant loudness.
fundamental frequency
The lowest-frequency component of a complex periodic sound.
harmonic spectrum
The spectrum of a complex sound in which energy is at integer multiples of the fundamental frequency.
hertz (Hz)
A unit of measure for frequency. One equals one cycle per second.
inferior colliculus
A midbrain nucleus in the auditory pathway.
frequency
For sound, the number of times per second that a pattern of pressure change repeats. Perceived as pitch.
medial geniculate nucleus
The part of the thalamus that relays auditory signals to the temporal cortex and receives input from the auditory cortex.
organ of Corti
A structure on the basilar membrane of the cochlea that is composed of hair cells and dendrites of auditory nerve fibers.
ossicle
Any of three tiny bones of the middle ear: malleus, incus, and stapes.
primary auditory cortex (A1)
The first area within the temporal lobes of the brain responsible for processing acoustic information.
rate saturation
The point at which a nerve fiber is firing as rapidly as possible and further stimulation is incapable of increasing the firing rate.
sine wave or pure tone
The waveform for which variation as a function of time is a sine function.
