The distinct regions of ER include?

Concept: Endoplasmic reticulum is found in all eukaryotic cells (ER). In animal cells, the ER typically accounts for more than half of the cell's membranous material.

The endoplasmic reticulum (ER) is a large, dynamic structure in the cell that is responsible for several tasks such as calcium storage, protein synthesis, and lipid metabolism. The numerous duties of the ER are carried out by distinct domains such as tubules, sheets, and the nuclear envelope. 

Several proteins have been discovered that contribute to the overall architecture and dynamics of the ER, but many questions remain concerning how the ER changes shape in response to cellular signals, cell type, cell cycle status, and organism development.

The ER is divided into two functionally separate types: smooth endoplasmic reticulum (SER) and rough endoplasmic reticulum (RER).

The presence of protein-synthesizing particles, known as ribosomes, attached to the RER's outer surface distinguishes the two.