: any of the minute tubules in eukaryotic cytoplasm that are composed of the protein tubulin and form an important component of the cytoskeleton, mitotic spindle, cilia, and flagella
Illustration of MICROTUBULE
Tubular structure enclosed by a membrane found within animal and plant cells. Of varying length, they have several functions. They help give shape to many cells and are major components of cilia and flagella, participate in the formation of the spindle during cell division (mitosis), and assist the movement of vesicles from the cell bodies of nerve cells toward the ends of those cells' long extensions (axons) and back to the cell bodies.