ABSTRACT
Hair cells are the sensory receptors in the inner ear. Auditory hair cells in the cochlea detect pressure waves to mediate hearing. Vestibular hair cells in semicircular canals, utricule, and saccule detect head movement and orientation. e hair cells are named so because of their characteristic structure at the apical surface of the cell called the hair bundle (see Figure 18.1). Mechanical stimuli such as sound pressure, acceleration, or gravity arrive through the extracellular structure at the hair bundle where it is turned into neural spike-train signals. How dierent mechanical stimuli are captured, ampli-ed, and encoded by hair cells is an important question in the inner ear science. e hair bundles have sophisticated structure and characteristic shapes depending on dierent inner ear organs (Figure 18.1). Even within the same sensory organ, the hair bundle shapes vary considerably and systematically. Considering such diverse and systematically arranged bundle shapes, it is logical to assume that the hair bundle mechanics play a crucial role on the hair cell’s function.
