In animals, mitosis occurs in two places. The first is in the development of the embryo, and the second is in special tissues in the organs to replace tired and old cells.
Mitosis is the division of cells with an end result of cell enlargement and differentiation. There are two phases that occur during cell division: karyokinesis and cytokinesis. Karyokinesis is the division of the nucleus; when the cytoplasm divides, it is known as cytokinesis. Mitosis results in the replacement of cells in the skin, long bones and lymph glands. Mitosis duplicates all parts of the cells, including the DNA.