Endoplasmic reticulum (ER) is a network of interconnected sacs (cisternae). Depending on the presence of ribosomes on the surface of their membrane, ER can be rough or smooth. Smooth ER does not have ribosomes on the surface of its membrane. Smooth ER plays a part in lipid production and metabolism, as well as in the production of steroid hormones. It is also involved in detoxification of organic chemicals, products of natural metabolism, etc.
