Biological Membranes - A. N. Ogurtsov 2012

Structure and Functions of Biomembranes
Cell Membrane Structures
Endoplasmic Reticulum

Ever since the invention of the optical Microscope and the Discovery of the cellular Structure of biological objects featuring a well-developed Endoplasmic reticulum, Two Types of endoplasmic reticulum have been distinguished:

1) smooth endoplasmic reticulum (SER) with a smooth surface,

2) rough endoplasmic reticulum (RER), whose surface is studded with nucleoprotein particles known as Ribosomes.

Within The Cell, The endoplasmic reticulum appears as a continuous, interconnected network of flattened sacs (cisternae), vesicles, and tubules (Figure 11).

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Figure 11 - Diagram of endoplasmic reticulum membranes

The rough endoplasmic reticulum consists of numerous parallel cisternae interconnected to form an intracellular communication network. This system allows products synthesized on the endoplasmic reticulum membranes to be transported either to other PARTS OF THE cell or to the extracellular environment. Protein Synthesis from Amino Acids takes place in the ribosomes attached to the membranes of the endoplasmic reticulum.

One of the primary Functions of the smooth endoplasmic reticulum—referred to as the sarcoplasmic reticulum in Muscle Cells—is the uptake of Calcium Ions, which are subsequently released into the Cytoplasm during muscle fiber contraction in response to a stimulus. For this reason, the sarcoplasmic reticulum is frequently described as a calcium store.

The smooth endoplasmic reticulum is particularly abundant in cells specialized for ion transport, such as the glandular Cells of the gastric mucosa.



Last update: 13/08/2026

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