Fenestrae in the rough endoplasmic reticulum of the exocrine pancreatic cells.
D000818:Animals; D046508:Culture Techniques; D004285:Dogs; D004721:Endoplasmic Reticulum; D005088:Exocrine Glands / Q000166:cytology*; D005613:Freeze Etching; D006801:Humans; D051379:Mice; D010179:Pancreas / Q000166:cytology*; D051381:Rats