An element is a pure substance that is made from a single type of atom. Elements are the building blocks for all the rest of the matter in the world. Examples of elements include iron, oxygen, hydrogen, gold, and helium.
Since the initial discovery that the adult brain contains stem cells that generate new neurons, an important question in neurobiology has been whether or not this adult neurogenesis is functionally important.
There are several sources of stem cells. Pluripotent stem cells can be isolated from human embryos that are a few days old. Cells from these embryos can be used to create pluripotent stem cell lines âcell cultures that can be grown indefinitely in the laboratory.Pluripotent stem cell lines have also been developed from fetal tissue (older than 8 weeks of development).In late 2007, scientists identified conditions that would allow some specialized adult human cells to be reprogrammed genetically to assume a stem cell-like state. Pluripotent stem cells can give rise to any type of cell in the body except those needed to support and develop a fetus in the womb. 2  Stem cells that can give rise only to a small number of different cell types are called multipotent.