Force and Ion Channels (IMAGE) University of California - San Diego Caption Inside the cell, calcium ions are released from a structure called the endoplasmic reticulum (ER). Forces applied to the bead cause ion channels in the ER to open mechanically (shown in red above), rather through biochemical signaling chemically (shown in green below). Credit Jie Sun/UC San Diego Usage Restrictions Please credit Jie Sun/UC San Diego License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.