Endoplasmic Reticulum Structure, Types and Functions In 189 | Avccs

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
e.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