Continuum Mechanical Model of the Outer Hair Cell Free

Knowledge of the mechanical properties of the outer hair cell (OHC) is essential for understanding its electromechanical action. To provide insight into underlying mechanics, we developed a finite‐element‐model of the OHC. The model contains both an intracellular viscous fluid and a homogeneous shell‐like structure for the basolateral wall, including anisotropic viscoelastic material properties. We found that the viscosity of the intracellular fluid could not yield the frequency dependent behaviour of the measured impedance. Shear viscosity needed to be included in the basolateral wall to obtain an adequate representation. The required value of the dynamic viscosity is on the order of $103 mPa⋅s$ and, therefore, 1000 fold higher than for water. Furthermore, changing the compressibility of the basolateral wall from $106$ to $109 Pa$ suggests that the impedance is not significantly affected by this parameter. Finally, our calculations indicate that up to at least 10 kHz the measured impedances result from passive mechanical properties of the OHC.