Stem cells Flashcards
Definition of a stem cell
- Not terminally differentiated.
- Can divide without limit (low rate).
- Renew themselves. Each daughter cell has a choice, become stem cell or commit to terminal differentiation.
Function of a stem cell
Repair and maintain tissue.
Fate
Describes what the cell will become on the course of normal development.
Potency
Describes the range of different cell types it can become.
Potency decreases until their fate is determined.
Embryonic stem cells
Totipotent until week 3. Can become a cell that is fully functional, fully differentiated cells.
Totipotent
Can differentiate into any/all cell types.
Multipotent
Can differentiate into a few options.
Unipotent
Can differentiate into one option.
Determination
When the fate of the cell is determined. Even if phenotype is not visible yet.
Followed by differentiation.
Differentiation
When the cell changes function and structure, phenotype. Triggered by inductive interaction and asymetric cell division.
Inductive Interaction
Most straightforward way to make cells different. By exposing them to different environments, signals from neighboring cells.
Asymmetric cell division
Set of molecules divided unequally between the two daughter cells. The molecules act a determinant by directly or indirectly altering the pattern of gene expression.
Why is the rate of division slow?
To reduce risk of mutation.
It can be increased in case of extended damage.
