Computer illustration showing the normal human cell anatomy. Shown is the nucleus (purple, consisting of nucleolus (inner dark purple sphere) and nuclear envelope). Surrounding the nucleus is the rough endoplasmic reticulum (purple folds) and smooth endoplasmic reticulum (light pink tubes). Floating in the cytoplasm are the Golgi body (beige), mitochondria (pink), peroxisome (green ball), lysosome (red ball) and cytoskeletal elements (green and yellow tubes). The outside of the cell is the cytoplasmic membrane with it's protruding cilia (bottom left).