Centrosome consists of two cylindrical structures called centrioles. Centrioles lie perpendicular to each other. They are surrounded by amorphous pericentriolar materials. Each has a cartwheel-like organisation.

A centriole is made up nine evenly spaced peripheral fibres of tubulin protein.   The adjacent triplets are linked together. There is a proteinaceous hub in the central part of a centriole. The hub is connected to the triplets via radial spokes. These centrioles help in organising the spindle fibres and astral rays during cell division. They form the basal body of cilia and flagella.