BIOL 2021 Chapter Notes - Chapter 20.3: Cancer Stem Cell, Adult Stem Cell, Intestinal Epithelium
11 Feb 2018
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Document Summary
Transit amplifying stem cell: daughters of stem cells. Can divide rapidly, have a limited number of divisions, and then differentiate. Many more of them than stem cells. Differentiated cells can be continually replaced but a few stem cells. In transit from being a stem cell to a differentiated cell always remain. Advantages: division rate can increase rapidly when more cells are required, reduces the chances of mutations in stem cells because they have few divisions and divide slowly (prevents cancer) Cancer most often arises in self-renewing tissues (cells that divide fast: epidermis, intestinal epithelium, bone marrow. Cancer stem cells are few in number, divide slowly, and divide indefinitely. Most of the tumour is composed of transit amplifying cells: these die and are replaced. Committed progenitor cells (tac) are the same as transit amplifying cells. A limited number of divisions creates many differentiated cells. Stepwise commitment for differentiation: gradually narrow choices down for differentiation.
