What are Stem Cells?
Stem cells are a unique type of growth cell, they are the original building blocks of life for the developing embryo in the womb. They have two important characteristics that distinguish them from other types of cells. First, they are unspecialized cells that renew themselves for long periods of time, through cell division. The second is that under certain physiologic or experimental conditions, they can be induced to become cells with special functions such as the beating cells of the heart muscle or the insulin-producing cells of the pancreas. Stem cells are one of the most fascinating areas of todays biology. But just like many expanding fields of scientific inquiry, research on stem cells raises scientific questions just as rapidly as it generates new discoveries.
Types of Stem Cells There are three main different types of stem cells. They differ in their degree of differentiation and ability to self-renew:
- Embryonic stem cells - come from a five to six-day-old embryo. They have the ability to form virtually any type of cell found in the human body.
- Embryonic germ cells - are from the part of a human embryo or foetus that will produce eggs or sperm.
- Adult stem cells - are undifferentiated cells found among specialised or differentiated cells in a tissue or organ after birth.
