Centrioles

Centrioles are cytoplasmic structures made out of microtubules which are usually found near the nucleus at a site termed the centrosome. Each centriole consists of nine sets of microtubule triplets arranged as a cylinder and extending for only a relatively short distance. Two centrioles tend to associate together, aligned perpendicularly.

At each cell division, the centrioles duplicate and migrate to opposing ends of the cell. They form the integrating centres from which the mitotic spindles originate; chromosomes or chromatids are drawn via the spindles to the poles.

Centrioles are also involved in the formation of individual cilia, acting as a reference for microtubule formation.