A multi-nucleated cell is formed when a cell undergoes mitosis but not cytokinesis. A primary example of a cell type that undergoes nuclear division but not cytoplasmic division is a skeletal muscle cell.
Nuclear division among multicellular organisms is of two types: mitosis and meiosis. Mitosis, which is associated with repair and growth of the organism, is the process of producing two identical diploid daughter cells. Meiosis, meanwhile, is involved in generating four haploid sex cells called gametes that are used for sexual reproduction.
Prior to mitotic cell division, a process called interphase occurs in the nucleus, where the genetic material contained within the deoxyribonucleic acid, or DNA, is replicated. After interphase, mitotic division follows, which is comprised of four major phases: prophase, metaphase, anaphase and telophase. Mitosis starts during prophase where the chromosomes condense and the nuclear envelope begins to disintegrate.
The centromeres and kinetochores align on the equator during metaphase. In anaphase, the two chromatids that form are pulled apart to polar opposites of the cell. During telophase, the events in prophase are reversed, where the chromosomes begin to uncoil and the nuclear envelope reforms. Cytokinesis, which refers to the division of the cytoplasm, generally occurs at the end of telophase and produces two identical cells. In some cell types, the cells continue to grow in size instead of separating into distinct daughter cells. This is typical of myoblasts found in skeletal muscle fibers, which contain several nuclei inside their cells.