Mitosis

Mitosis is the process during which an eukaryotic cell divides its nucleus. Mitosis is the shortest phase of the cell cycle.

Subphases

The events during the mitosis happen continuously and are conventionally divided into four or five subphases (not every source treats the prometaphase as distinct phase).

Prophase

The condensation of the replicated chromosomes is the first sign that a cell enters into the prophase and into mitosis. Those are first visible as thin threads within the nucleus. The miotic spindle apparatus forms outside of the nucleus between the two centrosomes that separate themselves and begin to move towards opposite poles of the cell.

Prometaphase

The prometaphase begins with the break down of the nuclear membrane. The chromosomes attach through the kinetochore to the spindle.

Metaphase

The chromosomes arrange themselves in the equatorial plane of the spindle.

Anaphase

The chromatids separate and move to opposite poles of the spindle.

Telophase

New nuclear membranes form around each of chromosome sets and build two daughter nuclei.

Pathology correlation

In evaluating histologic sections, pathologists count the number of cells in field undergoing mitosis. An abnormally high number of cells undergoing mitosis may indicate a neoplasm.