How Do Muscles Know What Time It Is? (image) Helmholtz Zentrum München - German Research Center for Environmental Health Share Print E-Mail Caption The 'circadian clock' of muscle cells (shown here is the transverse section of a muscle fiber) controls an entire metabolic network. Credit © Helmholtz Zentrum München Usage Restrictions None Share Print E-Mail 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.