Transmission electron micrograph (TEM) of a liver cell. A hepatocyte is a cell of the main parenchymal tissue of the liver. Hepatocytes make up 70-85% of the liver's mass. These cells are involved in: a) protein synthesis, b) protein storage, c) transformation of carbohydrates, d) synthesis of cholesterol, bile salts and phospholipids, e) detoxification, modification, and excretion of exogenous and endogenous substances, f) initiation of formation and secretion of bile. Smooth endoplasmic reticulum is abundant in hepatocytes, whereas most cells in the body have only small amounts. Hepatocytes display an eosinophilic cytoplasm, reflecting numerous mitochondria, and basophilic stippling due to large amounts of rough endoplasmic reticulum and free ribosomes. The average life span of the hepatocyte is 5 months; they are able to regenerate. Magnification: unknown.