The two basic types of human cells, somatic cells and sex cells, mature and
increase in number through processes known as mitosis and meiosis, respectively.
a. Mitosis. Mitosis is the form of cell division that occurs in higher forms of
animal life, including man. This form of cell division consists of four phases (prophase,
metaphase, anaphase, and telophase) during which the chromatin material in the
nucleus undergoes various changes in arrangement, leading to the ultimate division of
the cell. The result of mitosis of a somatic cell is two daughter cells, each of which
possesses the same number of chromosomes as the parent cell (figure1-9). In
humans, each somatic cell contains 23 pairs, or 46 chromosomes.
Figure 1-9. Diagrammatic representation of mitosis.