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The Science and Ethics of Stem Cell Research Stem Cell Development Lesson 1 Stem Cell Development November 4, 2010 Warmup Which of the following is true of stem cells? (COPY THE ENTIRE STATEMENT FOR THE STATEMENTS YOU THINK ARE TRUE) 1. Stem cells are able to make more of themselves by dividing 2. Stem cells can differentiate (give rise to daughter cells that can develop into many types of cells). 3. Adult human bodies contain roughly 20-30% stem cells. 4. The word multipotent is used to describe a cell that can become ANY other type of cell in an organism. What will we learn about today? Where are embryonic stem cells found? How does their ability to differentiate change over time? NOVA video Stem Cells: Early Research http://www.pbs.org/wgbh/nova/body/stem-cellsresearch.html Homework: Review worksheet on back of the gold sheet An Overview of Early Development modeled with Play-Dough Fertilized egg Totipotent: Can become any cell in body or placenta Pluripotent: Can become any cell in body Totipotent stem cells Fate Decision Pluripotent stem cells (3-5 days old) Blastocyst Multipotent: Can become any cell within a specific germ layer or cell lineage Embryonic stem cells come from inner cell mass of blastocyst. Fate Decision Implantation Multipotent Gastrulation (day 14) leads to Primary Germ Cells Endoderm (inner)gdigestive tract, resp. track Mesoderm (middle)gbones, blood cells, heart Ectoderm (outer)gskin, CNS What your zygote might look like: The Zygote What your morula might look like: Early Cell Division Source: Florida Institute for Reproductive Science and Technologies Four-cell stage 2 days after fertilization Source: Florida Institute for Reproductive Science and Technologies Eight-cell stage 3 days after fertilization Courtesy: RWJMS IVF Program Source: Florida Institute for Reproductive Science and Technologies Morula 4 days after fertilization Source: Florida Institute for Reproductive Science and Technologies 16 cells What your blastula (blastocyst) might look like: Blastula 5 days after fertilization Source: Florida Institute for Reproductive Science and Technologies Courtesy: RWJMS IVF Program Five Day Embryo http://www.nationalgeographic.com/ngm/ Blastula (Blastocyst) This image has been released into the public domain. What your gastrula might look like: Sea Urchin Development One Cell to Blastula Stage 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 Early Mouse Development One Cell to Morula Stage Early Human Development Multipotent This graphic has been released into the public domain