Stem cells are the unspecialized cells in the human body that can become specialized cells, with new specialized cell functions. An example of a stem cell is the bone marrow stem cell that is able to turn into specialized blood cells, such as white blood cells and red blood cells. The new cell types have new special functions, that can produce antibodies, combat infection and transport gases. It is called “stem cell” because one function stems from the other. Stem cells have properties of developing into a array of cell types in the body. They can function as a repair system by dividing without a limit to help other cells. When they divide, each cell is able to either become another cell type with new special functions, such as blood cells, brain cells, or to stay as a stem cell. Stem cells can proliferate many times which means they can expand the number of cells by the continuous division of single cells into two identical daughter cells. With their special regenerative abilities, they propose new potentials for treating diseases like diabetes or heart disease.
Stem cells are classified into four types based on their origin, stem cells from embryos; stem cells from the fetus; stem cells from the umbilical cord; and stem cells from the adult. Each of the four types can be grouped into subtypes. Embryonic cells are derived from embryos, and many are derived from embryos that have been fertilized in vitro and then donated for research.
These primitive cells that come from a five day pre-implantation embryo
that is capable of dividing without differentiating for a prolonged period in culture, and develops into the three primary germ layers. Fetal stem cells are primitive cell types found in the organs of fetuses.(Bongso) Fetal Stem Cells are split into two types, pluripotent stem cells and hematopoietic stem cells. Pluripotent stem cells are found in the fetuses, and hematopoietic stem cells are found in cord blood. Human fetal stem cells can be used by many people including children and adults suffering from many different diseases. An adult stem cell is an undifferentiated cell in a tissue or organ that can renew itself and can differentiate to help the major specialized cell types of the tissue or organ. The job of the adult cell is to maintain and repair the tissue in which they are found. Adult stem cells have been found in many organs and tissues, including brain, bone marrow, peripheral blood, blood vessels, skin, teeth, skeletal muscle, heart, gut, liver, ovarian epithelium, and testis.(National Institutes of Health) In a lot of tissues, evidence shows that some types of stem cells are pericytes, which are cells that compose the outside layer of small blood vessels. Stem cells may remain un-dividing for a long time until they are needed to maintain tissues, by disease or tissue injury.
Human embryonic and adult stem cells each have advantages and disadvantages regarding potential use for cell-based regenerative...