The principal function of the cytocenter (centrosome) and its centrioles is formation of microtubules and spatial organization of their structure in both the interphase and cell division (cytoplasmic network, axonemes of cilia and flagella, cell division spindle). The image depicts a pair of centrioles that are cut longitudinally. Each centriole is a cylinder 0.2 μm long; its wall comprises nine triplets of microtubules. The triplets are arranged like turbine blades.

Two centrioles are oriented perpendicular to each other; they are not identical. One of them is a mother centriole that is more mature while another is a daughter centriole emerging as a result of mother centriole replication. Both centrioles are surrounded by material with proteins, which are able to initiate microtubule assembly. The microtubules of cell division spindle are formed at the distal end of mother centriole. There, the matrix is condensed to subdistal appendages. Doublets of microtubules for a ciliary axoneme are also formed there, to be more accurate, at the end of the basal body. At the top of the image, one may see a stress fiber that is constituted by some parallel actin filaments (microfilaments). In the cytoplasm, some RER fragments are also found.