Stem Cells Flashcards
What is a stem cell?
Less differentiated self-renewing cells
What is a totipotent stem cell?
Can form a complete organism; present in embryo
E.g. Embryonic stem cells, Induced pluripotent stem cells
What is a pluripotent stem cell?
Can form many tissue types but not complete organism; present in embryo
E.g. Germ cells, fetal stem cells
What is a multipotent stem cell?
Can form different types of cells within an organ but not a different organ or cell type; present in adults
E.g. Mesenchymal stem cells, hematopoietic stem cells
What is a unipotent cell?
Can form only one type of cell; present in adults
What are the two fates of the daughter cells of stem cell division?
One remains a stem cell
The second divides and differentiates
What are transit-amplifying cells?
Rapidly proliferating cells that undergo several divisions before differentiating
Already partially differentiated
What is a niche?
The microenvironment of stem cells, determines fate of daughter stem cells
What provides the niche for hematopoeitic stem cells during embryonic development? Adult?
Liver - embryonic
Bone marrow - adult
Where are intestinal stem cells called and where are they found?
Lgr5+ stem cells and they are found in the crypt
How are stem cells maintained in the intestine?
Niche cells secrete Wnt protein which stimulates cell proliferation
What can embryonic stem cells be used for?
Development of specialized cells for transplantation into the patient
What are induced pluripotent stem cells (iPS cells)?
Reprogrammed adult cells
What are irradiated fibroblast cells?
Cells that cannot divide, but still metabolize and produce growth factors
Used to create medium to maintain ES cells
What two inhibitory growth factors keep cells in an undifferentiated state?
Leukemia inhibitory factor (LIF) - mouse cells
basic fibroblast growth factor (bFGF) - human cells
