Cell A close-up of the inside of one of the body's cells.
Mitochondria produce the energy necessary for the cell to function.
Around them, a tangle of extremely fine filaments called microtubules makes up the internal skeleton of the cell, which is filled with a gelatinous substance called cytoplasm. Nucleus Cytoplasm Mitochondrion Microtubule Reproduction strictly prohibited. All rights reserved, Immersion-Studios, Toronto, Canada. Reproduction strictly prohibited.