Diagram of the heart (IMAGE) American Institute of Physics Caption A diagram of the heart. Colors show the different types of proteins that connect cells, allow electricity to flow, and cause the heart to beat. Credit André G. Kléber Usage Restrictions Journalists may use this image only with appropriate credit. 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.