MICROANATOMY

Detailed explanation-1: -The endoplasmic reticulum (ER) is a continuous membrane system that forms a series of flattened sacs within the cytoplasm of eukaryotic cells. All eukaryotic cells contain an ER. In animal cells, the ER usually constitutes more than half of the membranous content of the cell.

Detailed explanation-2: -The ER is organized into a netlike labyrinth of branching tubules and flattened sacs extending throughout the cytosol (Figure 12-35). The tubules and sacs are all thought to interconnect, so that the ER membrane forms a continuous sheet enclosing a single internal space.

Detailed explanation-3: -rough endoplasmic reticulum (RER), series of connected flattened sacs, part of a continuous membrane organelle within the cytoplasm of eukaryotic cells, that plays a central role in the synthesis of proteins.