4. What parts of the body contain stem cells?Stem cells are the foundation of every tissue and organ in the body. The stem cells can be tissue-specific(also known as <somatic> or adult stem cells), which generatecells for the specific tissue and organ. They may be, for instance, blood-forming stemcells (which also divide into red blood cells, white blood cells and platelets). The blood-forming cells don’t regenerate liver cells or lung or any other type of cells, as each tissue and organ has its own stem cells.Source:5. What is a stem cell line ?A stem cell line is a group of stem cells that is cultured in vitroand can be propagated indefinitely. Stem-cell lines are derived from either animal or human tissues and come from one of three sources: embryonic stem cells, adult stem cells, or induced stem cells. They are commonly used in research and regenerative medicine.An embryonic stem cell line is created from cells derived from the inner cell mass of a blastocyst, an early stage, pre-implantation embryo. In humans, the blastocyst stage occurs 4–5 days post fertilization. To create an embryonic stem cell line, the inner cell-mass is removed from the blastocyst, separated from the trophectoderm, and cultured on a layer of supportive cells in vitro. In the derivation of human embryonic stem cell lines, embryos leftover from in vitro fertilization (IVF) proceduresare used. The fact that the blastocyst is destroyed during the process has raised controversy and ethical concerns.Compared to embryonic stem-cell lines, induced stem cells(iPSC) lines are also pluripotent in nature but can be derived without the use of human embryos—a process that has raised ethical concerns. Furthermore, patient-specific iPSC cell lines can be generated—that is, cell lines that are genetically matched to an individual. Patient-specific iPSC lines have been generated for the purposes of studying diseases and for developing patient-specific medical therapies.Source: 6. In what ways might the use of embryonic stem cells better than the use of adult stem cells?
Scientists have tried to determine whether stem cells from adult tissues have the same capabilities and potential as embryonic stem cells. Adult stem cells are less flexible and versatile than the embryonic ones. Embryonic stem cells have a greater differentiation potential and can develop in almost every type of cell in the human body, whereas adult stem cells can develop into a smaller number of cells, which makes their number of applications smaller. However, newer researches have shown that these cells have a great plasticity, which allows them to differentiate into a greater number of cells. Anyway, the embryonic stem cells seem to have a better capability of differentiating.Embryonic stem cells are capable of almost unlimited division, or proliferation, when placed in a culture while adult stem cells do not multiply so readily. The difficulty levelvaries as well; embryonic stem cells can be grown fairly easily in the laboratory whereas adult stem cells are not easily grown after isolation from mature adult tissues. Stem cell replacement therapies require large numbers of cells and the current difficulty in growing large numbers of adult cells means that their use for therapy at present is limited.Source:
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- Spring '17
- Starr, Brand
- Biology, Cellular differentiation, Embryonic stem cells