endoplasmic reticulum rough endoplasmic reticulum Planarian_Anatomy PMID:30143032 Network of interconnected, flattened, and/or tubular membrane, known as cisternae. This membrane is contiguous with the outer nuclear membrane. The endoplasmic reticulum is involved in both protein and lipid synthesis. https://orcid.org/0000-0003-2569-1939 | https://orcid.org/0000-0002-7535-4997