Stem Cell Development

1
The Science and Ethics of Stem Cell Research
Stem Cell Development
2
An Overview of Early Development
modeled with Play-Dough
Fertilized egg
Multipotent
3
The Zygote

• Take your Play-dough, and make one egg and sperm.
• Combine the egg and sperm. Congrats you just had
  fertilization occur. You now have a zygote.

4
The Zygote
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What your zygote might look like
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Morula

• Now its time for your zygote to grow and divide
  into more cells. The ball of cells is called a
  morula.
• Take your Play-dough, and divide the zygote into
  two cells.

7
Early Cell Division
Source Florida Institute for Reproductive
Science and Technologies
8
Morula

• Your cells continue to divide through a process
  called mitosis.
• Now divide the two cells into a total of four
  cells.

9
Four-cell stage 2 days after fertilization
Source Florida Institute for Reproductive
Science and Technologies
10
Morula

• Now divide the four cells again into a total of
  eight cells.

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Eight-cell stage3 days after fertilization
Courtesy RWJMS IVF Program
Source Florida Institute for Reproductive
Science and Technologies
12
Morula

• Your now ready for the final division to make
  your complete morula!
• Now divide the eight cells into a total of
  sixteen cells.

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Morula 4 days after fertilization 16
cells
Source Florida Institute for Reproductive
Science and Technologies
14
What your morula might look like
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Blastula

• Now your morula cells are ready to differentiate
  and make placenta or embryo cells.
• Take another color of Play-dough to make the
  pre-placenta.

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What your blastula might look like
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Blastula5 days after fertilization
Source Florida Institute for Reproductive
Science and Technologies
Courtesy RWJMS IVF Program
18
Five Day Embryo- The Blastula starts to form a
hollow ball
http//www.nationalgeographic.com/ngm/
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Blastula- now it attaches itself to the uterus
wall
This image has been released into the public
domain.
20

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/galle
  ry.php?AssetcelldivCategoryseaurchinsTypevide
  o

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Early Mouse Development One Cell to Morula Stage
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Early Human Development
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Gastrula

• Now your embryo cells from your blastula are
  ready to differentiate into three new layers.
• Take two more colors of Play-dough to make the
  inner, middle, and outer layer.

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What your gastrula might look like
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The Three Layers

• Outer Layer stem cells from this layer
  differentiate into skin cells, nervous system,
  pituitary gland, salivary glands
• Middle Layer stem cells from this layer
  differentiate into bones, heart, muscles, testes,
  ovaries, kidneys
• Inner Layer stem cells from this layer
  differentiate into pancreas, thyroid gland,
  liver, parts of the digestive system

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Multipotent
This graphic has been released into the public
domain