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Medical Term:


Pronunciation: mī′krō-tū′byūl

Definition: A hollow, cylindric cytoplasmic element, 25 nm in diameter and of variable length, that occurs widely in the cytoskeleton, cilia, and flagella of cells; microtubules play a role in the maintenance of cell shape and increase in number during mitosis and meiosis, in which they are related to movement of the chromosomes by the nuclear spindle.