EMBRYONIC DEVELOPMENT tutorial http://learn.genetics.utah.edu/content/stemcells/scintro/

Zygote to Embryo Development http://www.sumanasinc.com/webcontent/animations/content/stemcells.html mesoderm

EARLY DEVELOPMENT http 3 LAYERS OF GASTRULA a. Ectoderm, outer layer, skin, nerves, sense organs b. Mesoderm, middle layer, circulatory, muscle, reproductive & excretory systems. c. Endoderm, inner layer, digestive tract, respiratory system

Gastrula 3 tissue layers DIGESTIVE TRACT

Stem Cells JIM THOMPSON FIRST SCIENTIST TO ISOLATE EMBRYONIC STEM CELLS 1995

What is a stem cell? Embryonic neural cell Two characteristics: 1. Grows & proliferates -can maintain a pool of cells type 2. When stimulated can differentiate into a specialized cell type (tissue or cell type) http://www.wwnorton.com/college/biology/discoverbio5/animation/ch_11/start.html Embryonic neural cell

Stem cell differentiation steps 1. Stem cell formedvia cell signaling (mitosis) from surrounding tissue. Can create more stem cells or become differentiated 2. Formation of progenitor cell precursor to a specific cell type 3. Becomes differentiated. Becomes a specific cell type; heart, muscle, nerve http://www.wwnorton.com/college/biology/discoverbio5/animation/ch_11/start.html

Unipotent Stem Cell Can only be one type of cell Unipotent Stem Cell Can only be one type of cell. Red blood cell or sperm cell

Stem Cells can become any type of body tissue http://www.sumanasinc.com/webcontent/animations/content/stemcells_scnt.html

Embryonic & Adult Stem cells This tutorial has several tabs. Start with embryonic, then adult, then Nuclear Transfer. To answer the differences between embryonic and adult stem cells, click Cell Specialization. http://ns.umich.edu/stemcells/D_030206.html

Sometimes organ transplants are not possible Rejection of tissue Infection risk Injection of stem cells directly into an organ is possible, more direct, easier

Stems Cells hold the key to treatment of major diseases Click the link to find out all the possible uses for stem cell treatments. http://media.hhmi.org/biointeractive/click/Stem_Cell_Therapies/01.html

Issues with Embryonic Stem Cell Only 1 in 10 embryos provide useable stem cells It is difficult to culture them to form only one type of cell Can have uncontrolled growth of cells, may form a tumor in patient Transplant rejection-must match tissue type, just like blood typing Patient must take anti-rejection drugs-immuno-suppressants for their entire life. Gene expression-uncertainty of how and when genes will turn on/off Some people have issues with ethics of using embryonic cells

Bioethical Issues Bioethics-discipline dealing with ethical implications of biological research, especially in medicine. It considers social, moral & religious aspects. Moral status of embryo-are they human or property? Should embryos be destroyed? “Excess” embryos-fertility clinics. Used for research or adopted? Do we need embryonic stem cells if adult stem cells work? Adult stem cells are not totipotent.