The network of thin tissue that runs throughout the cytoplasm and helps move materials to all cell parts is called the endoplasmic reticulum (ER).

There are two types of ER:

* Rough endoplasmic reticulum (RER): Has ribosomes attached to its surface, which are responsible for protein synthesis. The RER helps fold and modify proteins before they are transported to other parts of the cell.

* Smooth endoplasmic reticulum (SER): Lacks ribosomes and is involved in lipid and steroid synthesis, detoxification, and calcium storage.

Both types of ER act as a network of interconnected membranes that provide a pathway for the movement of materials throughout the cell. This is essential for cell function, as it allows for the transport of nutrients, waste products, and signaling molecules to different parts of the cell.