Cytoskeleton: network of protein filaments found in all cells.

  <--  Fibroblast cells - cells of connective tissue that are responsible for extra-cellular matrix and secreting connective tissue proteins, such as collagen.
   Fluorescent light micrograph of fibroblast cells, showing their nuclei (purple) and cytoskeleton. The cytoskeleton is made up of microtubules of the protein tubulin (yellow) and filaments of the protein actin (blue).  

The cytoskeleton supports the cell's structure, allows the cell to move and assists in the transport of organelles and vesicles within the cell.
Magnification: x980 when printed 10cm wide.