Summer 2007 Workshop in Biology and Multimedia for High School Teachers. Why Can’t We Grow New Arms?. An Introduction to Stem Cells and Regeneration. Image by mila zinkova from commons.wikimedia.org. http://en.wikipedia.org/wiki/Image:Sea_star_regenerating_legs.jpg , image by Mila Zankova.
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Summer 2007 Workshop
in Biology and Multimedia
for High School Teachers
Why Can’t We Grow New Arms?
An Introduction to Stem Cells and Regeneration
Image by mila zinkova from commons.wikimedia.org
http://en.wikipedia.org/wiki/Image:Sea_star_regenerating_legs.jpg, image by Mila Zankova
Greek myth says that zeus had prometheus chained to a rock for bringing fire to humans. Every day an eagle would come and eat his liver. By the time the eagle came back the next day, the liver had grown back.
Your liver can regenerate too!
Will There be a day When your arm or leg will grow back?
Did you know that salamanders can also regenerate lost limbs? This probably makes you wonder:
“Why can’t we grow new arms?”
In order to answer that question, You will need to understand a little bit about how the salamander is able to regrow an arm and how your arm is formed in the first place.
These are the questions you should be able to answer by the end of this lesson.
As you proceed through the lesson, click on the green links to answer the questions on your worksheet. As you scroll over the links, some of them have instructions as to where on the page you should look for the answers.
Mouse embryonic stem cells
Learn about stem cells
Answer question 1
B. There are two types of stem cells, embryonic and adult. Find out how both are isolated, some similarities, and some differences.
Pluripotent, embryonic stem cells originate as inner mass cells with in a blastocyst. The stem cells can become any tissue in the body, excluding a placenta. Only the morula's cells are totipotent, able to become all tissues and a placenta.
Embryonic vs. Adult Stem Cells
Where the cells are found
Answer question 2
Photograph taken by Patrick Coin
Read about limb regeneration in salamanders
Visual of limb regeneration in salamander
Limb Regeneration Movie
Answer questions 3-6
Vertebrate Limb Development
Answer questions 7-9
As you can see, creating an arm is a very complex process that requires a number of different genes. Each step can trigger the next, and more and more genes and environmental factors get involved.
http://commons.wikimedia.org/wiki/Image:Limb_bud.pngorg by Peter Znamenski
Why do we form a scar instead of a new limb?
Answer question 10
Now that you know what stem cells are, how a limb develops and how a salamander’s limb can regenerate, you may be wondering…
What do stem cells have to do with limb development and regeneration?
This image shows how a hematopoietic stem cell (an adult blood stem cell) can differentiate into all of the different types of blood cells.
http://stemcells.nih.gov/info/basics/basiImage courtesy of HINcs4.asp
To get a better Idea of this concept play the virtual stem cell laboratory from children’s Hospital boston
Answer questions 11-12
Answer question 13.
This leads us to our final question…
Image by emo_boy from http://www.abstractinfluence.com/forums/album_pic.php?pic_id=8414
Photo Credit:US National Oceanic and Atmospheric Administration
Image from http://commons.wikimedia.org/wiki/Image
Now find an article about studies into limb regeneration.
Read the Article and write down the source. Then, summarize the article and hand it in with your “Stem Cells and Regeneration” worksheet.
Use some of the links below to answer question I. Then, write about your own opinions. Be sure to explain how you feel and give reasons for youropinion.
If you would like more information on stem cells, regeneration or development, go back to any of the links in this presentation or check out some of the following: