Figure 5.

(A) Amplitude and phase of the mechanical impedance of the OHC, Z_OHC, as a function of stimulus frequency. Up to about 3 kHz, Z_OHC resembles that of a compliance with slope near −6 dB/octave (−4.8 dB/octave) and an initial phase near −90°. For higher stimulus frequencies, the impedance associated with fluid coupling (open circles) between the micropipette and the AFL constitutes an appreciable part of the measured impedance, thus preventing estimation of Z_OHC above about 5 kHz. (B) Axial compliance of the OHC, C_OHC, as a function of cell length. C_OHC increases with cell length (r = 0.54, n = 26): C [m/N] = (2.37 ± 0.17)⋅10⁶ L [m]. For the regression analysis, the axis intercept could be held constant at zero because when made variable it was found to be not significantly different from zero; C = (2.64 ± 0.83)⋅L − (20 ± 61). (C) Amplitude and phase of the impedance of the AFL (F46–7) used for the measurements of cell OHC29 (see Material and Methods for calibration details). The compliance of the AFL was 29 m/N.