The main function of mitosis in human somatic cells is growth and tissue repair. Mitosis produces two genetically identical daughter cells, allowing for the replacement of damaged or dead cells and enabling organismal growth. This process ensures maintaining chromosome number in all somatic cells, which is crucial for normal cellular function and stability. Unlike meiosis, mitosis does not reduce chromosome number or create gametes but focuses on cellular proliferation within tissues. Effective mitosis is essential for wound healing, immune response, and maintaining homeostasis in rapidly renewing tissues such as skin and the gastrointestinal lining.

Reference: Molecular Biology of the Cell, Alberts et al., 6th Edition.