Cancer, Stem Cells and Cancer Stem Cells Flashcards
What is a stem cell?
A cell which can self-renew and differentiate
What does totipotent mean?
can make everything
What does pluripotent mean?
Can make all somatic cells
What does multipotent mean?
can make many different cell types
What was bi-/tri- etc. potent mean?
can make 2/3 etc. cell types
What does unipotent mean?
Can only differentiate into one cell type
What is potency?
A cell characteristic, not a stem cell characteristic - every cell can differentiate, divide or stay as it is
What is the most potent (totipotent) cell?
A zygote
Describe embryonic stem cells
Cultured in vitro from cells of the early embryo
Pluripotent
Immortal
Describe adult stem cells
Exist in many tissues
Normally contribute the tissue maintenance
Numbers, properties and functions vary
Describe somatic stem cell characteristics
Rare Slow cell cycle Symmetric or asymmetric cell division Unspecialised Present in many adult tissues Usually respect germ layer boundaries
What is symmetric division?
Where they either make two new stem cells or two differentiated cells
What is asymmetric division?
They make one new stem cell and one differentiated cell
What is the most common type of division?
Asymmetric division (80%)
How have stem cells developed so they divide asymmetrically?
The stem cell will only be a stem cell if one cell self renews and stays anchored to the niche and one cell differentiates and leaves
OR
Feedback mechanisms, if you have too many differentiated cells it will send a strong negative feedback which inhibits the cell from dividing or differentiating. Or if there isn’t enough differentiated cells it will send a week negative signal