The human body is made up of trillions of cells, and only a tiny portion of these are stem cells─ unspecialized cells capable of renewing themselves through cell division─even after long periods of inactivity. Stem cells play the part of organizing the remaining cells so they can repair, restore, and sustain the major organs in your body. Under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions.
In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, such as the pancreas and the heart, stem cells only divide under special conditions. Your body consists of heart stem cells, liver stem cells, stomach, and skin stem cells, just to name a few.
Adult Stem cells have the remarkable potential to develop into multiple cell types in the body during early life and growth. In addition, they serve as an internal repair system for many tissues, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential to either remain as a stem cell, or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.