Endoplasmic Reticulum Structure, Types and Functions

In this article we will discuss about:- Endoplasmic Reticulum Structure, Types and Functions

• In 1897, observed by Garnier and named it as ergastoplasm
• In 1945, first described by Porter, Claude and Fullman
• In 1953, term given by porter
• Present in all eukaryotes
• All cells do not have Endoplasmic reticulum. It is generally absent in egg and embryonic cells

Endoplasmic Reticulum Structure

Components of endoplasmic reticulum

Cisternae

• Formed by projection of nuclear membrane
• They bear ribosomes on the surface
• Contain ribophorin that bind the ribosomes

Vesicles

• They are oval or rounded, vacuole like element
• Many vesicles are free in the cytoplasm

Tubules

• They are tube like extensions
• Tubules are irregular and branched
• Free of ribosomes

Types of Endoplasmic Reticulum

I) Rough Endoplasmic Reticulum

• Ribosomes binds with help of ribophorin protein
• Mainly composed of cisternae
• Abundantly occurs in cell which are engaged in protein synthesis and secretion
• Mass of RER in cyton of nueron is called missals granules
• g. Liver, pancreas and goblet cells

II) Smooth Endoplasmic Reticulum

• Ribosomes and ribophorins are absent
• Mainly composed of tubules
• Occurs especially in those cells which are almost inactive in protein synthesis
• It is well developed in cells that synthesis lipids
• Mass of SER in retinal cell is called myeloid bodies

Functions of Endoplasmic Reticulum

• It gives mechanical support so also called cytoskeleton of cell
• Intracellular exchange: Transport of materials in cytoplasm from one place to another through the ER
• Provides site for protein synthesis, because rough ER has ribosome’s
• Lipids synthesized by smooth ER
• Detoxification of drugs

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