Does the geometrical arrangement of the outer hair cell stereocilia perform a fluid-mechanical function?

Abstract

Conclusions. Our experiments qualitatively show that the geometrical structure of the inner ear may have the features of a micro-pump. To further substantiate this hypothesis, additional experiments, particularly on in vivo preparations, are needed. Objective. To introduce some new ideas about the functional purpose of the geometric arrangement of the outer hair cell stereocilia. Analogies to some recently developed valveless micro-pumps are pointed out. To illustrate these points, comparative experiments were performed using a simplified macro model. Methods. Specific structures of the organ of Corti were simulated in a partially open, partially closed acrylic tank. This rough approximation allows the visualization of fluid flows that are generated as a result of the relative motions between the tectorial membrane and the reticular lamina. Results. It was shown that the arrangement of the cochlear elements not only forces fluid to flow in a one-way direction, but also generates a fluid stream that flows through the “outlets” between each two V or W formations of stereocilia. These fluid streams are directed towards the inner hair cells.

• Outer hair cell sterocilia
• geometrical arrangement
• functional meaning
• valveless micro-pumps
• inner ear geometry