Stem Cell Research Glossary

Glossary of Terms

Adult stem cells-undifferentiated cells that have the potential to become a limited number of specific cell types. These multipotent cells are found in small quantities in umbilical cord blood and adult tissues. There is limited evidence that one type of adult stem cells can produce cells that naturally come from another type of adult stem cells.

Amniotic stem cells- cells found in the amniotic fluid that surrounds a fetus. They are not pluripotent like embryonic stem cells, but research has shown that they can differentiate into more cell types than adult stem cells.

Blastocyst-an embryo of 30-150 cells before uterine implantation. It is composed of an outer layer of cells that will become the placenta, a fluid-filled cavity and an inner cell mass.

Cloning-the process of genetic duplication.

Differentiation-the process by which stem cells acquire the features of specialized adult cells such as those found in heart, brain and pancreatic tissue.

Embryo-a medical term that refers to a group of cells that arise from a fertilized egg (after merging of egg and sperm). An embryo does have the potential to become a complete organism. The embryonic stage ends at eight weeks of development.

Embryonic stem cells-primitive (undifferentiated) cells that have the potential to become a wide variety of specialized cell types (i.e., cardiac myocytes, neuronal, pancreatic). They are pluripotent cells derived from the inner cell mass of a blastocyst. Embryonic stem cells are NOT embryos and cannot become a complete organism.

In vitro fertilization (IVF)-an assisted reproduction technology in which fertilization (merging of sperm and egg) occurs outside the body.

Multipotent-capacity to become a limited number of types of tissues and cells in the adult body.

Pluripotent-capacity to become many types of tissues and cells in the adult body.

Reproductive cloning-the use of cloning technology to create a child.

Somatic cell nuclear transfer (SCNT)-the replacement of genetic material (nuclear DNA) in an unfertilized egg with genetic material from an adult somatic cell (e.g., skin cell). Stem cells that genetically match the adult somatic cell donor can be derived from this process. See graphic.

Therapeutic cloning-the use of cloning technology to help in the search for possible cures and treatments for diseases and disabilities.