Stem cells are undifferentiated biological cells that can differentiate into specialized cells and can divide (through mitosis) to produce more stem cells.
There is a homeostatic equilibrium between the replication, self-renewal, and differentiation of stem cells and the death of the mature, fully differentiated cells.
Stem cell are characterized by two important properties
- Self-renewal, which permits stem cells to maintain their numbers.
- Asymmetric division, in which one daughter cell enters a differentiation pathway and gives and rise to mature cells, while the other remains undifferentiated and retains its self-renewal capacity.