Auditory 1-3 Flashcards
what are the 3 compartments of the cochlea?
the scala vestibuli,
the scala media,
the scala tympani
The fluid filled scala vestibuli is connected to
the scala tympani by the ________
helicotrema (a hole in the BM located at the apex of the cochlea)
During an oscillatory sound wave the BM move up towards the ______ during rarefaction and down
towards the ______ during compression.
scala vestibuli,
scala tympani
A collapse of the
endocochlear potential due to a mutation in the gap junction subunit ______, which is important in active transport of potassium in the ______ , is the major cause of congenital deafness
connexin 32, stria vascularis
~28,500 Type I Auditory Nerve fibers (ANFs) innervate_____. This occurs because _____ Type I ANFs innervate a single IHC.
~3,500 Inner Hair Cells (IHC), 10-30
OHCs respond to changes in voltage with a change in length – they are _______
“electromotile”
The mechanical amplification of the displacement of the BM by OHCs is called the _________.
cochlear amplifier
Ototoxic antibiotics, such as _______, can block the transduction channel of the OHCs and, with prolonged action, can kill them resulting in deafness
streptomycin and gentamycin
For periodic stimuli, such as low-frequency pure tones, ANFs ______their action potentials in that the neurons tend to fire action potentials only at particular phases (i.e., compression or rarefaction) of the ongoing sound waveform
“phase lock”
An unusual type of sensorineural hearing disorder (not necessarily accompanied by hearing loss) called _______results from some problem with neural transmission from IHC to ANFs, or in the ANF function itself.
auditory neuropathy
What are the 3 main acoustical cues for sound source localization
1) Interaural time delays (ITDs) :because the ears are physically separated in space by the head. The source will generate different times of arrival of the sound at the two ears, or ITDs.
2) Interaural level differences (ILDs): The head becomes an obstacle. For sounds of high frequency ( the head essentially creates an “acoustic shadow” for the far ear as sounds with wavelengths on the order of the diameter of the head and smaller are reflected off the near side of the head. As expected, ILDs are small in magnitude for low frequency sounds and increase in magnitude for high-frequency sounds. Therefore, ILDs are primarily useful for localization of high frequencies.
3) Monaural spectral shape: Spectral shape cues arise from direction- and frequency-dependent reflection and diffraction of the pressure waveforms of sounds by the pinna that result in broadband spectral patterns, or shapes, that change with location
Interaural level differences (ILDs) are coded in the_______
lateral superior olive
The neurons comprising the medial superior olive (MSO) receive excitatory inputs from both ears via cells of the ______ on both sides
anteroventral cochlear nucleus (AVCN)
The primary auditory cortex (A1) (Broadmann’s area 41) is arranged in a tonotopic map with neurons responding to _____ located anteriorly and neurons responding to ______ more posterior.
lower frequencies,
higher frequencies
Sound possesses two primary qualities that are decoded by the auditory system: ___________
amplitude (or intensity) and frequency.