microtubule

/muy'kroh tooh"byoohl, -tyooh"-/, n. Cell Biol.

a hollow cylindrical structure in the cytoplasm of most cells, involved in intracellular shape and transport. See diag. under cell.

[1960-65; MICRO- + TUBULE]

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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.

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▪ biology

      tubular structure of indefinite length, constructed from globular proteins called tubulins, which are found only in eukaryotic cells. Microtubules have several functions. For example, they provide the rigid, organized components of the cytoskeleton that give shape to many cells, and they are major components of cilia and flagella (cellular locomotory projections). They participate in the formation of the spindle during cell division (mitosis). They also assist the movement of organelles (e.g., mitochondria), as well as the movement of vesicles from the cell bodies of neurons to the axonal tips and back to the cell bodies.

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