Stem cells
Every human being at the very initial stage of his life can be traced back to a single cell that came into existence from the union of egg and sperm (see the drawing below).
Everything in our body is generated from this very cell, named zygote. The cells keep dividing and after several days develop an early embryo, named blastocyst, made of several tens of embryonic stem cells.
Just these very cells develop the following generation of stem cells, named hemopoietic and stromal stem cells. The information about hemopoietic and stromal stem cells is given below.
Since abortion is impossible at such an early stage, embryonic stem cells can be derived in laboratory conditions only, by means of in vitro fertilization (IVF). Besides, there is no special necessity to derive them, for it is much easier to get hemopoetic and stromal stem cells, which can be cultured into nearly any type of a human tissue and cell nowadays.
Thus, the following two types of stem cells are of practical interest:
These cells are predecessors of all cells and tissues in the human body. Find out more about other cell types.
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