The endoplasmic reticulum is a system of interconnected tubes and pouches inside a cell, like a hollow funnel cake.There are two different specialized areas of the endoplasmic reticulum (ER), each with different functions. One is called the smooth ER and the other is called the rough ER.he endoplasmic reticulum is a system of interconnected tubes and pouches inside a cell, like a hollow funnel cake.