Blastocyst
A mammalian embryo before it implants in the uterus. An outer ring of cells surrounds the inner cell mass, which contains undifferentiated embryonic cells.

Differentiation
The process of transition from stem cell to specialized cell, such as a blood, heart or bone cell.

DNA
Deoxyribonucleic acid. A complex molecule containing genetic instructions for making everything the body needs.

Embryonic germ cells
Undifferentiated stem cells that become sperm or eggs.

Embryonic stem cells
Self-renewing, undifferentiated stem cells removed from the inner cell mass of a blastocyst and grown in culture.

FACS
Fluorescence-activated cell sorting. A technique scientists use to separate different types of cells based on surface protein markers.

Free radicals
Chemically unstable atoms that can damage cells. Free radicals are toxic by-products produced when cells convert food to energy.

Gastrulation
An early stage of mammalian embryonic development in which stem cells divide into three layers called the endoderm, mesoderm and ectotoderm.

Growth factor
A substance that stimulates cells to grow or inhibits their growth.

Hematopoietic
Type of stem cells that produce all the red and white blood cells in the body’s blood and immune systems.

Multipotent
A stem cell with the ability to develop into a limited number of cell types.

Osteogenic
Type of stem cells that develop into bone and its connective tissue.

Oxidation
A chemical reaction inside cells which uses oxygen to convert food to energy.

Plasticity
The ability of adult stem cells to change their normal developmental pathway and produce a different type of specialized cell.

Pluripotent
A stem cell capable of developing into every type of cell derived from the endoderm, mesoderm and ectoderm of the early embryo.

Progenitor or precursor cell
A partially differentiated cell midway between a stem cell and a specialized cell.

Reprogramming
Manipulating stem cells in a way that changes their developmental pathway from one type of cell to another.

Somatic (or adult) stem cells
Stem cells found in tissue other than the egg, sperm, or pre-gastrulation embryo.

Stem cell
A cell capable of self-renewal and development of specialized cells.

Also:

Michael Clarke

Sean Morrison

Unlocking the Secrets of Stem Cells