Smooth Endoplasmic Reticulum

**Semantic type:** Cell Component

**Definition:** An internal membrane structure of the eukaryotic cell. Biochemically similar to the rough endoplasmic reticulum, but lacks the ribosome binding function. Tends to be tubular rather than sheet like, may be separate from the rough endoplasmic reticulum or may be an extension of it. Abundant in cells concerned with lipid metabolism and proliferates in hepatocytes when animals are challenged with lipophilic drugs.

**Synonyms:** - Smooth-Surfaced Endoplasmic Reticulum - sER