Centrioles are cylindrical cell structures composed of microtubules, typically found in pairs within animal cells. They play a crucial role in cell division by aiding in the formation of the spindle apparatus, which separates chromosomes during mitosis and meiosis. Centrioles also contribute to the organization of the cell's cytoskeleton and are involved in the formation of cilia and flagella. Each centriole is made up of nine sets of triplet microtubules arranged in a specific pattern.