Stem Cells
& Tomorrow's Human
How are ES cells obtained?
Cells from the inner cell mass region of the blastocyst are grown in a cell culture. The culture contains a nutrient broth which is coated in mouse embryonic skin cells that provide nutrients and a base for the human ES cells to stick to. ES cells grow, and when they crowd the dish, they are divided and moved to fresh culture dishes.
(Citation 4)
ES cells can specialize spontaneously as they grow. When these growths group together, they form embryoid bodies. These collections can then differentiate (another word for specialize) to different types of cells. To create a particular cell type (i.e. muscle cell), scientists manipulate the properties of the cell culture to give rise to the different cell types. Scientists can also place desired genes in ES cells to induce them to specialize.
(Citation 4)
How are ES cells differentiated?
Embryonic Stem Cells
Embryonic stem (ES) cells are taken from blastocysts---embryos that are about 3-5 days old. These stem cells are pluripotent, which means that they have the potential to specialize into any of the various types of cells that are found in the human body. The ES cells used for research come from donations made by In Vitro Fertilization clinics; they can only be donated with the consent of the donors. (Citation 5)
Colonies of human embryonic stem cells (Image Citation 5)
ABOVE: Embryoid bodies (Image Citation 7)
LEFT: The specialization of embryonic stem cells.
(Image Citation 6)
LEFT:This diagram shows the potential varieties that embryonic stem cells can specialize into. (Image Citation 8)