What are stem cells?
Stem cells are master cells of the body — cells from which all other cells with specialized functions are created. Under the right conditions in the body or a laboratory, stem cells divide to form more cells, called daughter cells. These daughter cells either become new stem cells (self-renewal) or become specialized cells (differentiation) with a more specific function, such as blood cells, brain cells, heart muscle or bone. Stem cells are unique — no other cell in the body has the ability to self-renew or to differentiate.
Stem cells are the basic building blocks of the body. They have the potential to develop into over 200 different cell types that define the body’s make-up. In theory, they can divide without limit to replenish other cells. The two hallmark properties of stem cells are: • Stem cells can divide indefinitely in culture, retaining their original properties. • Stem cells can divide into a more specialized cell, such as an insulin-secreting beta cell and dopamine-secreting cells.
Stem cells are a class of undifferentiated cells that are able to differentiate into specialized cell types. Commonly, stem cells come from two main sources: • Embryos formed during the blastocyst phase of embryological development (embryonic stem cells) and • Adult tissue (adult stem cells). Both types are generally characterized by their potency, or potential to differentiate into different cell types (such as skin, muscle, bone, etc.).
Stem cells are unspecialized cells that have two defining properties: the ability to differentiate into other cells and the ability to self-regenerate. The ability to differentiate is the potential to develop into other cell types. A totipotent stem cell (e.g. fertilized egg) can develop into all cell types including the embryonic membranes. A pleuripotent stem cell can develop into cells from all three germinal layers (e.g cells from the inner cell mass). Other cells can be oligopotent, bipotent or unipotent depending on their ability to develop into few, two or one other cell type(s).2 Self-regeneration is the ability of stem cells to divide and produce more stem cells. During early development, the cell division is symmetrical i.e. each cell divides to gives rise to daughter cells each with the same potential. Later in development, the cell divides asymmetrically with one of the daughter cells produced also a stem cell and the other a more differentiated cell.
Why not use other cells? Types of Stem Cells About Cord Blood Stem Cells About Adult Stem Cells About Embryonic Stem Cells About Spore-Like Cells Human stem cell What are stem cells? Stem cells are primal undifferentiated cells (cells that do not have a specialized or “mature” function) and retain the ability to differentiate (adapt or change to serve a specific function or environment) into other cell types. More simply stated, stem cells can become other types of cells to help the body where needed. This ability allows them to act as a repair system for the body, replenishing other cells as long as the organism is alive. Medical researchers believe stem cell research has the potential to change the face of human disease by being used to repair specific tissues or to grow organs. Yet as government reports point out, “significant technical hurdles remain that will only be overcome through years of intensive research.”(1) The study of stem cells is attributed as beginning in the 1960s a
