Human epithelial cells. Fluorescent light micrograph of human epithelial cells in culture. The nuclei, which contain the cells genetic information DNA (deoxyribonucleic acid), have been dyed blue. Actin filaments, part of the cells cytoskeleton, are dyed green. The cytoskeleton is responsible for intracellular transport, cell structure and motility. Mitochondria, which produce energy for the cell, have been dyed orange. Epithelial cells are found lining every surface on the human body.
