Hydra's Intestinal Tissue and Nerve Cells (IMAGE) Kiel University Caption Fibers of intestinal tissue (in red) surround the nerve cells (in green) of the freshwater polyp Hydra. Credit Image: Christoph Giez, Dr. Alexander Klimovich 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.