RER - Granular reticulum is not visible as a distinct object with the light microscope. However, in certain cell types which produce large amounts of protein, basophilic areas can be observed in the region containing RER. The basophilia is due to the high content of RNA of the ribosomes associated with granular reticulum. Observe the distinct basophilia at the base of the pyramidal acinar cells of the pancreas (basophilia is in the cytoplasm surrounding the nucleus)
SER - The agranular reticulum CANNOT be viewed with the light microscope.