Transmission electron micrograph showing hepatocyte cytoplasm for rough endoplasmic reticulum. Magnification 15,000x Hepatocyte, a cell of the main tissue of the liver, liver cell. Cytoplasm, the cell substance between the cell membrane and the nucleus, containing the cytosol, organelles, cytoskeleton, and various particles. Endoplasmic reticulum, a network of tubular membranes within the cytoplasm of the cell, occurring either with a smooth surface (smooth endoplasmic reticulum) or studded with ribosomes (rough endoplasmic reticulum), involved in the transport of materials.