What are stem cells and where do they come from? Stem Cells

B - B Explore the scientific evidence for the potential of stem cell research. A - B2 2.8 – Explain how stem cells from embryos can differentiate into all other types of cells, but that stem cells lose this ability as the animal matures. Totipotent, pluripotent, multipotent (from potential) A* - B2 2.7 – Explain that cells have a limit to the number of divisions they undergo, the Hayflick limit; stem cells and cancer cells have no Hayflick limit.

Hayflick limit Leonard HAYFLICK and Paul MOORHEAD found that cells divided a maximum of 50 times. Their research was conducted on lung cells from humans. They also found that long lived animals had larger Hayflick Limits and short lived had smaller Hayflick Limits, eg.  Mouse – 15 divisions  Tortoise – 110 divisions

What are the consequences? Of having a Hayflick limit Of no Hayflick limit?

Stem Cells Have no Hayflick limit. Can be found in:- Are undifferentiated Are in three categories: –Totipotent –Pluripotent –Multipotent

Why don't we live forever? Because we get sick? get old? get hurt and can't heal? Each one results from a failure of the body's ability to grow, maintain or repair itself - functions that depend on our stem cells.

Stem cells form the basic building materials for the human body. This makes them good candidates for restoring tissues that have been damaged by injury or disease. For decades, researchers have been studying the biology of stem cells to figure out how development works and to find new ways of treating health problems.

How would stem cell therapy work? The goal of any stem cell therapy is to repair a damaged tissue that can't heal itself. This might be accomplished by transplanting stem cells into the damaged area and directing them to grow new, healthy tissue. It may also be possible to coax stem cells already in the body to work overtime and produce new tissue. To date, researchers have found more success with the first method, stem cell transplants.

Stem cell research - The Cons "We should not mess with human life." Some argue that stem cell research in the far future can lead to knowledge on how to clone humans. It is hard to say whether this is true, but we have seen devastating consequences of other research, even with good intentions, such as nuclear research.

Stem cell research - The Pros Stem cell research can potentially help treating a range of medical problems. It could lead us closer to cure: Parkinson’s Disease Alzheimer’s Disease Heart Diseases, Stroke and Diabetes (Type 1) Birth Defects Spinal Cord Injuries Replace or Repair Damaged Organs Reduced Risk of Transplantation (You could possibly get a copy of your own heart in a future heart-transplantation) This could also give significant social and economic benefits for individuals and the society.

Home work Select Stem cells Click on: What are some different types of stem cells ? Find out the names and functions of the 5 stem cell types Have a look at what are stem cells too but beware of the model they use!