Stem Cells

Stem cells are undifferentiated cells.The zygote undergoes mitosis repeatedly to become a mass of undifferentiated cells which have the potential to become any of the cell types.During embryonic development, cells gradually lose their undifferentiated state and become specialised, taking on specific functions.The embryonic stem cells are involved in forming the three primary germ layers (ectoderm, mesoderm, and endoderm), which in turn give rise to different tissues and organs.As development progresses, some stem cells remain in the body, particularly in adult tissues, and are known as adult or somatic stem cells. These adult stem cells have a more limited ability to differentiate compared to embryonic stem cells.Stem cells can undergo cell division several times and are the source of new cells which are too differentiated to undergo mitosis.