Stem Cells Flashcards
What are stem cells?
- Unspecialised cell
- Can renew and divide indefinitely
- Capable of differentiating into specialised cells under appropriate conditions
How are stem cells unspecialised?
Absence of tissue-specific structures that allows it to perform specialised functions
How do stem cells renew and divide indefinitely?
- Ability to proliferate (replicate many times)
- Can undergo symmetrical or asymmetrical cell division
- symmetrical: 2 daughter stem cells formed
- asymmetrical: 1 daughter stem cell & 1 daughter cell committed to differentiate (RBC)
How can they differentiate into specialised cell types under appropriate conditions?
They differentiate through the trigger of intercellular and extracellular signals
- intercellular signals: cytoplasmic factors encoded by genes in the genome of a cell. The factors send signals to the nucleus via transcription factors 𐃘 turning on and off various genes
- extracellular signals:
A) growth factors surrounding the cell, which may be secreted by other cells
B) physical contact with a neighbouring cell
What are the different development potential of stem cells?
Totipotent
Pluripotent
Multi potent
What are totipotent stem cells?
They are able to differentiate into any cell types to for, whole organisms
What are pluripotent stem cells?
They are able to differentiate into almost all cell types to form organs
What are multipotent stem cells?
They are able to differentiate into a limited range of cell types
What kind of embryonic stem cells are there?
what are their potency?
What are their functions?
1) zygotic stem cells, totipotent
Gives rise to all cell types to form whole organisms
2) embryonic stem cells, pluripotent
Derived from the inner cell mass of blastocyst
Gives rise to almost all cell types to form organs - possible due to ESC giving rise to cells in all 3 germ layers
