These types of cells are distinguished by two properties, pluripotency and their replication abilities. The pluripotency of embryonic stem cells distinguishes these cells from ‘adult’ stem cells that can be seen in bodies all ages. While hES cells can produce all cell types in the body, ‘adult’ stem cells are multipotent, meaning they can only produce the cells in which organ or tissue they are found in. In distinct conditions, hES cells are capable of regenerating continuously. hES cells have the ability to generate every 220 cell types in the human body, meaning that each Embryonic cell is pluripotent. Human Embryonic stem cells are also able to form cells of all three basic body layers. This means that potentially, these cells can produce any cell or tissue that are required to keep the body alive and healthy. This allows these types of cells to be used as essential tools in both research and regenerative medicine, because they can continuously regenerate themselves for continued research or clinical …show more content…
During this stage of development, the blastocysts are hallow balls consisting of approximately 150 cells and are as small as a pinhead. At this stage of development, the blastocyst development is very unique, as there are two types of cells involved. There is a layer called the trophectoderm, more commonly known as the outer layer, which becomes the placenta. There is also a minute group of about thirty cells, more commonly known as the inner cell mass, which becomes the embryo. hES cells are isolated from the blastocyst when the inner cell mass is removed and cultured in the lab. Once the hES cells have been isolated, they can continuously grow in a culture dish, containing a nutrient-rich culture medium. When the hES cells replicate and spread over the dish, some of the cells are removed to form a stem cell line. Many hES cells are taken from embryos developed from eggs that have been fertilised outside the woman’s body, which are then donated for research purposes. While hES can form all of the tissues in the body, they cannot form the other tissues that are required for a complete individual to form. Embryonic cells are also immortal, expressing abnormal levels of telomerase, which is a type of protein produced to ensure the telomere ends of chromosomes are maintained at each cell separation, and the cells do not undergo deterioration.
In 1995, James A. Thomson began work as the chief pathologist