The spindle, also called the spindle apparatus, is a body formed within a cell at mitosis or meiosis, which takes parts in the distribution of chromatids to the two daughter cells. It is composed of a gel and is commonly but not always ellipsoidal in shape. The spindle appears at metaphase, and chromosomes become arranged at its equator. It contains many microtubules, some running from spindle-attachments, or centromeres to one spindle pole, others from pole to pole. The microtubules are responsible for movement apart of the chromatids during anaphase. See mitotic spindle for more details.