In this sketch, James Hudspeth suggests how the movement of a hair cell's cilia bundle (top left) opens ion channels at the tips of the cilia. When the bundle tilts to the right, tip links from the higher cilia pull up the gates of the ion channels on adjoining, shorter cilia. A close-up shows how a tip link between two cilia opens an ion channel on the shorter cilium. Even more highly magnified at the right, the open channel allows ions into the cell. A cluster of myosin molecules in the taller cilium is shown in green and some actin filaments are shown in blue. Illustration: Jennifer Jordan, RCW Communications, Inc. (adapted from a sketch by James Hudspeth, HHMI, University of Texas Southwestern Medical Center at Dallas)