Multimedia

Magnified image of a human blastocyst. Green area is the inner cell mass, the cluster of cells along the inner wall of the blastocyst that provide the embryonic stem cells. The red cells are trophectoderm. Photo courtesy of Gary Smith, University of Michigan.

Differentiated human embryonic stem cells, known as embryoid bodies. Embryoid bodies are spherical colonies of embryonic stem cells, seen only in culture and containing all three germ layers: endoderm, mesoderm and ectoderm. Photo courtesy of Gary Smith, University of Michigan.

Human embryonic stem cells differentiated into neurons. Photo courtesy of Sue O’Shea, University of Michigan

Neural stem cells from the adult mouse brain forming neurons. Blue stain indicates nuclei, green stain indicates cell processes that communicate with other cells. Photo by Maria Morell, University of Michigan.

Several human embryonic stem cell colonies. University of Michigan photo.

Mouse embryonic stem cells forming neuronal cells. Photo by Matt Velkey, University of Michigan.

This highly magnified human blastocyst (the early embryo) is about the same size as a period at the end of a printed sentence. Embryonic stem cells are created from the inner cell mass from leftover embryos at this stage after egg and sperm are mixed in a dish in a fertility clinic. Excess embryos used for research would never be used for fertility purposes, but are routinely discarded as medical waste. Courtesy of Gary Smith, PhD

A magnified image (200x) of a thousands of human embryonic stem cells growing together as a colony (the silver cluster of cells in the center of the image) growing on top of mouse feeder cells (the dark filamentous structures). These cells can become any cell type in the body and divide indefinitely. Courtesy of Jack Mosher, PhD.

High magnification image of human embryonic stem cells differentiated into neurons (red cells) by treating cells with a growth factor. These could be used to study the development of the nervous system, birth defects or to replace cells lost to injury, aging or diseases such as Parkinson’s. Courtesy of Sue O'Shea, PhD