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Stem Cell Powerpoint with teacher notes.pdf
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- 2. Many breeds oflarge dogs are affected by hip dysplasia. This degenerative disease affects their hind legs, hindering mobility. Watch as scientists at Vet-Stem explain how stem cells are used as a cure for these animals. Clip 1: Hip dysplasia Clip 2: Vet-Stem’s Dr. Harman
- 3. The video clipof the German Shepherd raises many questions. Imagine if Dr. Bob Harman, the lead scientist at Vet Stem, were to come to class for a discussion. What kind of questions would you ask him? – What is a stem cell? – Can this be done in humans? • What other questions do you have?
- 4. What are stemcells? • Stem cells can indefinitely divide and give rise to a variety of other cell types. • One example is the hematopoietic stem cell which gives rise to all blood cells in the body.
- 5. Two types ofstem cells • Embryonic stem cells are pluripotent and can give rise to all types of cells in the body • Adult stem cells are only multipotent and are more limited in the types of cells that they can give rise to.
- 7. • Totipotency –the ability to produce any type of cell. Ex: zygote (embryo + placenta) • Pluripotency – the ability to produce any cell lineage. Ex: can differentiate into germ layers • Multipotency- the ability to produce any kind of cell within a cell lineage. Ex: blood stem cell • Unipotency- the ability to produce only one kind of cell. Ex: hepatocytes (liver cells)
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- 10. Differentiation Events • Embryonicstem cells enter the first differentiation event at the 8 cell morula stage. • Each of these totipotent cells express two genes Cdx2 and Oct 3/4. • At the morula stage the innermost cells no longer express the Cdx2 gene. • This loss of gene expression due to position is the differentiation event.
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- 13. Differentiation • As thesepluripotent cells divide they continue to be affected by their changing position. • This changing position and resulting change in environment will result in other differentiation events. • Three stem cell lines
- 14. Three Germ Layers (threestem cell lines) • As gastrulation occurs, three layers of pluripotent stem cells are created. – Ectoderm- gives rise to skin and nervous system – Mesoderm- gives rise to blood, bone, and muscle – Endoderm- gives rise to gut and lungs http://www.tvdsb.on.ca/saunders/courses/Onli ne/SNC1D/Vejvoda/biology/human- conception5.jpg
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- 18. Differentiation con’t • Ascells differentiate, they lose some of their ability to become all types of cells. • These multipotent stem cells develop from the three germ layers during gastrulation.
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- 20. The stem cellblog
- 21. Skin derived precursorcells. (photo courtesy Freda Miller)
- 22. A stem cellemerging from rat bone marrow. By stimulating the release of stem cells after a heart attack, the healing process could be accelerated. Photograph: Imperial College London
- 23. Stem Cell: PaulLeonard/Photo Researchers
- 24. Unipotent Cells • Asmultipotent cells divide creating either new stem cells or a specialized (unipotent) cell. • These specialized cells have a variety of characteristics that suit their role in the body.
- 25. A scanning electronmicroscope image of normal human blood. Photo by Bruce Wetzel, courtesy of the National Cancer Institute http://www.fi.edu/learn/heart/blood/images/red- blood-cells.jpg http://people.eku.edu/ritchisong/301images/Red_W hite_Blood_cells.jpg
- 26. Scanning electron microscopeimage of a mammal's lung. Image by Dartmouth Electron Microscope Facility
- 27. http://www.sciencemuseum.org.uk/a ntenna/musclemachines/images/cells. jpg © Dennis Kunkel Researchby Stelios Andreadis has produced this smooth muscle progenitor cell derived from a hair follicle, which expresses calponin (in red), a marker for smooth muscle cells. The cell nucleus is shown in blue. (Credit: Image courtesy of University at Buffalo) – Science Daily.com)
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- 33. Stem Cell Mysteries •There are several questions that need to be answered through stem cells research – How can stem cells remain unspecialized and self renewing for many years? – What are the signals that cause stem cells to become specialized cells? – Can we make multipotent stem cells revert to pluripotency?
- 34. Curing Diseases • Howcan stem cells help to cure disease? • Consider the video clip you watched at the beginning of the presentation, now imagine someone whose knee has degenerated. Explain how stem cells could be used as a cure.
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- 36. Curing Injuries • SpinalCord Injuries – There are currently between 250,000 - 400,000 Americans living with a spinal cord injury. More than 13,000 additional people are injured each year. – Every 41 minutes another person sustains a spinal cord injury – More than half of those injured are between the ages of 16-30 http://www.travisroyfoundation.org/pages/resources- stats.htm