Passage
Sound waves propagate through many conducting structures in the ear before they are transduced into neuronal signals. When sound waves reach the fluid-filled cochlea, they are detected by hair cells lining the basilar membrane. The cochlear spiral can be modeled as a resonator system because each section of the basilar membrane is sensitive to a specific frequency (Figure 1) .
Figure 1 Amplitude pattern of the basilar membrane for different frequenciesPresbycusis (age-related hearing loss) results from a combination of factors that lessens an individual's mechanical and/or neurological sensitivity to sound. Pure tone audiometry (PTA) is used to determine an individual's ability to detect different sound frequencies and can be used to evaluate presbycusis. A "pure" tone is characterized by a single sinusoidal waveform. An audiogram plots the relative intensity required of a given frequency to be detected by the individual (Figure 2) .
Figure 2 Audiogram of an elderly patient exhibiting presbycusis
-A sound wave used in PTA that causes resonance close to the apex of the basilar membrane has a relatively:

Question

Passage
Sound waves propagate through many conducting structures in the ear before they are transduced into neuronal signals. When sound waves reach the fluid-filled cochlea, they are detected by hair cells lining the basilar membrane. The cochlear spiral can be modeled as a resonator system because each section of the basilar membrane is sensitive to a specific frequency (Figure 1) .

Figure 1 Amplitude pattern of the basilar membrane for different frequenciesPresbycusis (age-related hearing loss) results from a combination of factors that lessens an individual's mechanical and/or neurological sensitivity to sound. Pure tone audiometry (PTA) is used to determine an individual's ability to detect different sound frequencies and can be used to evaluate presbycusis. A "pure" tone is characterized by a single sinusoidal waveform. An audiogram plots the relative intensity required of a given frequency to be detected by the individual (Figure 2) .

Figure 2 Audiogram of an elderly patient exhibiting presbycusis
-A sound wave used in PTA that causes resonance close to the apex of the basilar membrane has a relatively:

Quizplus · Accepted Answer

11ecba2d_12ee_142c_a3bf_f583cb098c18_MD0008_00 According to the passage, the basilar membrane is modeled as a resonator system. The resonant frequency of an object is the frequency that causes relatively large oscillations compared to other frequencies. The resonant frequency depends on the physical characteristics and geometry of the object. As shown in Figure 1, high frequencies resonate near the base of the basilar membrane, and low frequencies resonate near the apex. The frequency of a sound is associated with its perceived pitch (or tone). A sound with a high frequency is perceived to have a high pitch, and a sound with a low frequency (such as those near the apex) is perceived to have a low pitch. (Choice A) From the wave velocity equation (v = λf), wavelength is inversely proportional to frequency at a given velocity. Therefore, a low-frequency sound is characterized by a long wavelength. (Choice B) The resonant frequency depends on the physical characteristics and geometry of the object. Resonance is independent from the intensity of the sound source. (Choice D) A phase shift is the measure of the offset of a wave from a reference wave. A phase shift does not have an effect on resonance. Educational objective: The frequency of a sound is associated with its perceived pitch; high-frequency sounds have high pitches. The low-frequency sounds that cause resonance near the apex of the basilar membrane are characterized by low pitches.

Passage Sound Waves Propagate Through Many Conducting Structures in the Ear