MICROTUBULE

fine, hollow tubular structure of indefinite length, found within animal and plant cells. Constructed from globular proteins called tubulins, microtubules have several functions. They help give shape to many cells and are major components of cilia and flagella (cellular locomotory projections). They participate in the formation of spindle fibres during cell division (mitosis). They also assist the flow of materials from the cell bodies of nerve cells toward the ends of those cells' axons.