Figure 18. A. Location of the semicircular ducts in the head. Note that the anterior semicircular duct of one ear is in the same plane as the posterior canal from the other ear. AC = anterior semicircular canal; PC = posterior semicircular canal; LC = lateral semicircular canal. B. The structure of hair cells. Note that the kinocilium is longer and is attached to the tip of the other cilia by a filament. Tension on this filament will open ion channels and result in an increase in action potentials in the nerve (below). C. Structure of a christae. Note that all of the hair cells are polarized in the same direction. D. Structure of a macula. Note that the hair cells have different polarization.