What is the tunnel like structure in the cell??

Question

heeelp me.what is the long, winding tunnel that is part of the cell's interconnecting transport system??

Answer 1

its the organells in the cell.from the nucleus all the mRNA will go through the smooth and rough endoplasmic renticulum via transport vesical in cis and trans side of endoplasmic renticulum before secreted outside the cell or be using as one of the component inside the cell

Answer 2

that is the endoplasmic reticulum.  

And that's most of what I remember from high school.