Endoplasmatic reticulum (endoplasmatic = ″im Zytoplasma″; reticulum = ″kleines Netz″; abbreviated ER) is a richly branched canal system of flat cavities (cisterns) enclosed by membranes.
The ER is found in all eukaryotic cells (with the exception of mature erythrocytes); depending on the cell type, it is developed to varying degrees.
https://de.wikipedia.org/wiki/Endoplasmatisches_Retikulum (Wikipedia CC-by-sa-3.0)