Organelles within a liver cell

Colour-enhanced image of mitochondria (red), rough endoplasmic reticulum and smooth endoplasmic reticulum. Mitochondria are the energy factories within the cell. Rough endoplasmic reticulum is so-called because it has ribosomes (dark blue) attached to its outer surface. Smooth endoplasmic reticulum has no ribosomes attached and is seen towards the bottom of the image. The horizontal field width of the sample is 2.9 micrometres.