Strep throat is a contagious disease caused by infection with streptococcal bacteria, which causes inflammation and swelling of the mucous membranes lining the back of the throat and the tonsils.trep throat is a contagious disease caused by infection with streptococcal bacteria, which causes inflammation and swelling of the mucous membranes lining the back of the throat and the tonsils.
Once an egg cell is fertilized by a sperm, it will divide and become an embryo. In the embryo, there are stem cells that are capable of becoming all of the various cell types of the human body. For research, scientists get embryos in two ways. Many couples conceive by the process of in vitro fertilization. In this process, a couple's sperm and eggs are fertilized in a culture dish.
If the embryos have been kept in the freezer for one year or longer, parents may choose to: A second source of stem cells can be obtained from aborted fetuses, where the germ cells (ovaries and testes) are of particular interest. A third source of stem cells, known as multipotent stem cells, can be found in many types of adult tissue such as bone marrow, adipose tissue (fat), and umbilical cord blood. Adult stem cells are needed every day to replenish a variety of cell types in our body that normally wear out and die in large numbers.