What are the types and sources of stem cells found in humans?
During the embryonic stage of human development, embryonic stem cells (ES cells) can be obtained by extracting cells from very early embryos (4 to 7 days after fertilization). At this stage, they are totipotent, meaning that they have the ability to develop into any type of cell in the human body. Starting on the 6th day after fertilization, the cells begin to specialize. They then become pluripotent, which means that their ability to specialize is more limited. Pluripotent stem cells can be found in umbilical cord blood (collected from the umbilical cord immediately after) or more generally in the cells of the foetus. Finally, adult stem cells can be found in adult tissue and organs.
During the embryonic stage of human development, embryonic stem cells (ES cells) can be obtained by extracting cells from very early embryos (4 to 7 days after fertilization). At this stage, they are totipotent, meaning that they have the ability to develop into any type of cell in the human body. Starting on the 6th day after fertilization, the cells begin to specialize. They then become pluripotent, which means that their ability to specialize is more limited. Pluripotent stem cells can be found in umbilical cord blood (collected from the umbilical cord immediately after) or more generally in the cells of the foetus. Finally, adult stem cells can be found in adult tissue and organs. When an organism is fully developed, stem cells are referred to as multipotent, meaning that they can differentiate into only one type of specialized tissue cell (for example, epidermal stem cells can form any type of skin cells and hematopoietic stem cells present in bone marrow produce different types o
