Cell division and embryonic stem cells l Egg

Cell division and embryonic stem cells

l Egg cell l Sperm cell

l Egg and sperm meet

l Then the magic happens… the cells begin to divide and replicate First we have 2

l Then 4

l Then 8

Totipotent l Then 16 identical cells; we can use these as embryonic stem cells because they are identical (totipotent). Soon, they will begin to specialize and become (pluripotent).

l Remember: l l l Totipotent cells can become any cell off of the “total” list of cells. Pluripotent cells can become many (plural) different types of cells, but not all. This is why we want to be able to use the embryo before it begins to differentiate, so these cells can grow up to be anything they (we) want (them) to be.

Pluripotent These cells in red Have become Cells for the Placenta and Amniotic Membrane l The blue Cells are Changing into The various cells Of the human body l

l l The cells shown in red and blue are now pluripotent. Those are the cells that we will be able to collect from the umbilical cord at the time of delivery. They can become many different cell types, but NOT all different cell types. Thus the embryonic stem cells are the most desirable for research.

l l As an adult, we have a small number of stem cells (found mostly in the bones), but they are already highly specialized. We use them in such cases as bone marrow transplants.