How Do Stem Cells Differentiate?

Stem cells have two functions; they divide (proliferate) and their daughter cells become specialized tissues as they lose the ability to divide. This change-from a dividing cell to a specialized cell-is called differentiation.

Proliferation and Self-renewal

When stem cells divide into two cells, one cell is still a stem cell (self-renewal); the other is a daughter cell that starts to become specialized.

Totipotent Cells and Multipotent Cells

Embryonic stem cells are totipotent, meaning they can give rise to any and all tissues in the body. Adult stem cells are usually multipotent, meaning they can differentiate into some, but not all, cell types.

Daughter Cells

Each time a daughter cell divides, it become more specialized (differentiated); eventually, it can no longer divide.

Specialized Cells and Tissues

When daughter cells are fully differentiated (mature), they have functions not found in the stem cell; muscle cells contract, gland cells secrete molecules, blood cells carry oxygen and skin cells protect the body.

Some Tissues Have More Regenerative Power

The liver can regenerate from a small fragment; until recently, the only neurons known to regenerate were odor receptors. Stem cells have been found in many tissues, but not all tissues have the same ability to regenerate.

References

• Development; Gerald Karp and NJ Berrill; Mcgraw-Hill, 1981
• Principles of Anatomy and Physiology; Gerald J. Tortora, M.S. and Sandra Reynolds, Ph.D. Grabowski;Harper Collins, 2003

Resources

• National Institutes of Health