Smooth endoplasmic reticulum

Smooth endoplasmic reticulum is a network of short, continuous tubes througout the cytoplasm in which there are no ribosomes on the membrane surfaces. It dyes with acid stains under the light microscope.

It functions to:

• package material for transport to the Golgi apparatus
• synthesize lipids and derivatives e.g. in adrenal cells, it contains the enzymes necessary for conversion of cholesterol to steroids
• detoxify drugs or foreign proteins, particularly in the liver
• compartmentalise cellular components e.g. the specialised sER of skeletal muscle, termed the sarcoplasmic reticulum, which sequesters calcium