What is the meaning of a stem cell?
A stem unit is a cell that is able to replace itself repeatedly to become cells of tissue of the body and practically any organ. Embryonic stem cells are cells extracted from the blastula, the very early embryo, that have an extraordinary ability to replicate in vitro, that is in a test tube, and become the part of any tissue. Adult stem cells are cells, after birth, found in an organism. Until recent times, it was thought that adult stem cells could formulate themselves as blood cells, bone and connective tissue only. But recent improvement in science, over the past 5 years, has revealed that adult stem cells have capabilities analogous to embryonic stem cells.
