Activated Platelets with Filopodia (IMAGE) University of Pennsylvania School of Medicine Caption These are activated platelets with filopodia. Credit John Weisel, PhD, Perelman School of Medicine, University of Pennsylvania 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.