The centrioles inside the animal cells form the asters of spindle. These centrioles are found within the centrosome which gives rise to microtubules. Asters are the star-shaped microtubules formed inside the nucleus. They are present at two corners of an animal cell during the process of mitosis in cell division. They attach themselves to the chromosomes via spindle fibers for the equal segregation of the number of chromosomes in the dividing cells.