1. Stem Cell Development Lesson 1 The Science and Ethics of Stem Cell Research

2. An Overview of Early Development modeled with Play-Dough Fertilized egg Totipotent stem cells Totipotent : Can become any cell in body or placenta Fate Decision Pluripotent stem cells (3-5 days old) Blastocyst Pluripotent: Can become any cell in body Implantation Fate Decision Gastrulation (day 14) leads to Primary Germ Cells Endoderm (inner)  digestive tract, resp. track Mesoderm (middle)  bones, blood cells, heart Ectoderm (outer)  skin, CNS Multipotent: Can become any cell within a specific germ layer or cell lineage Embryonic stem cells come from inner cell mass of blastocyst. Implantation Fate Decision Gastrulation (day 14) leads to Primary Germ Cells Endoderm (inner)  digestive tract, resp. track Mesoderm (middle)  bones, blood cells, heart Ectoderm (outer)  skin, CNS Multipotent: Can become any cell within a specific germ layer or cell lineage Multipotent

3. What your zygote might look like:

4. The Zygote

5. What your morula might look like:

6. Early Cell Division Source: Florida Institute for Reproductive Science and Technologies

7. Four-cell stage 2 days after fertilization Source: Florida Institute for Reproductive Science and Technologies

8. Eight-cell stage 3 days after fertilization Courtesy: RWJMS IVF Program Source: Florida Institute for Reproductive Science and Technologies

9. Morula 4 days after fertilization 16 cells Source: Florida Institute for Reproductive Science and Technologies

10. What your blastula (blastocyst) might look like:

11. Blastula 5 days after fertilization Courtesy: RWJMS IVF Program Source: Florida Institute for Reproductive Science and Technologies

12. Five Day Embryo http://www.nationalgeographic.com/ngm/

13. Blastula (Blastocyst) This image has been released into the public domain.

14. What your gastrula might look like:

15. http://www.luc.edu/depts/biology/dev/urchindv.htm (courtesy of Dr. J. Hardin, Univ. of Wisconsin) http://www.exploratorium.edu/imaging_station/gallery.php?Asset=celldiv&Category=seaurchins&Type=video Sea Urchin Development One Cell to Blastula Stage

16. Early Mouse Development One Cell to Morula Stage

17. Early Human Development

18. This graphic has been released into the public domain Multipotent