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Incoming links: Smooth endoplasmic reticulum
Endoplasmic reticulum Created 2026-10-14 Updated 2026-10-18
The endoplasmic reticulum is a membrane-enclosed network of tubules and flattened sacs in a typical eukaryotic biological cell. Its continuous boundary encloses the ER lumen, separate from the cytosol, and connects with the outer nuclear envelope. Rough endoplasmic reticulum and smooth endoplasmic reticulum are regions of this network.[ref]
The Endoplasmic Reticulum. The Cell: A Molecular Approach, 2nd edition by Geoffrey M. Cooper; The Endoplasmic Reticulum, opening paragraph and Figure 9.1: continuous membrane and nuclear-envelope connection
One endoplasmic reticulum network with rough and smooth regions
. Original conceptual cross-section: blue interiors connect, while attached ribosomes distinguish rough regions. Shapes and dimensions are illustrative, not measured fluorescence or electron microscopy. Details.
Smooth endoplasmic reticulum 2026-10-18
Smooth endoplasmic reticulum lacks attached ribosomes. Specialized regions support lipid metabolism and processing of foreign compounds; the endoplasmic reticulum also stores and releases calcium ions. Regional specialization does not split the network into two separate organelles, nor make every smooth region perform every function.[ref]
The Endoplasmic Reticulum. Molecular Biology of the Cell, 4th edition by Bruce Alberts and others; Smooth ER Is Abundant in Some Specialized Cells, Figures 12-38A and 12-38B and calcium-storage paragraphs