Mouse Photoreceptor Sensory Cilium (IMAGE) University of Pennsylvania School of Medicine Caption Isolated mouse photoreceptor sensory cilium. Red is the rootlet, which helps connect the cilium to the cell. Green is the axoneme, the central part of the cilium. Scale bar 5 microns. Credit Qin Liu, M.D., Ph.D. and Eric A. Pierce, M.D., Ph.D., University of Pennsylvania School of Medicine Usage Restrictions None 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.