cell differentiation and stem cells Flashcards
define the different stem cell potencies
- omni - can differentiate into any cell type including placenta
- pluri - can differentiate in to any cell type other than placenta
- multi can differentiate into a few cells types
- unipotent a reserve population that can be used to regenerate new cells of one lineage
Give 3 examples of ectoderm derived cells
skin cells, neuron, pigment
Give 3 examples of mesoderm derived cells
bone, cartilage, muscle
cardiac muscle
heart, blood blood vessels
rbc
Give 3 examples of endoderm derived cells
gut tube derivatives eg: lung, thyroid, pancreas
what do transcription factors do
determine which genes are switched on and off
what is the relationship between transcription factors and specification
assorted TFs can be switched off and on at various points during specification thereby changing the gene expression (and so spec/differentiation)
what can influence cell fate?
internal and external factors eg ECM
what are the 2 commitment stages and what are their features
1) Specification - capable of differentiation autonomously in a neutral env. but can be reversed in a non-neutral env
2) determination - capabale of differentiating even when moved about. Pretty much irreversible
Define:
Dedifferentiation
Transdetermination
Transdifferentiation
Dedifferentiation in which a cell reverts to a less-specialized progenitor state within a discrete lineage(F allows re-population of the stem cell population).
Transdetermination in which a cell dedifferentiates to a less-committed progenitor state and then switches lineages to re-differentiate to a cell type in a new lineage.
Transdifferentiation in which a cell moves directly from one lineage to another without moving through a dedifferentiated or pluripotent intermediate €
what can cause necrosis
trauma, disease, infection
Define the process of apoptosis
Membrane blebbing, shrinkage of cell, nuclear collapse (nuclear fragmentation, chromatin condensation, chromosomal DNA fragmentation), apoptoticbody formation. Then, engulf by white blood cells
define necrosis process
Membrane disruption, respiratory poisons and hypoxia which cause ATP depletion, metabolic collapse, cell swelling and rupture leading to inflammation
give 3 treatments for necrosis
antioxidants
debridement
maggot debridement
What benefits does maggot debridement have?
secrete antibacterial substances
do not eat healthy tissue
promote healing
why does apoptosis happen in foetal development
fingers and toes, caudal eminence, nervous system, 50% more cells than needed
50-?bn cells ___ each___ in an ___
die, day, adult
what are caspases?
initiators and executioners(!) of apoptosis
which are initiator caspases?
2,8,9,10
which are executioner caspases
3,6,7
describe the intrinsic and extrinsic apoptosis pathways
intrinsic: cell notices it’s a bit knackered, targets the mitochondria. Cytochrome C is released which activates Caspase 9, then activating the executioner caspases
Extrinsic:
cell receives death ligands bound to its death receptors. Caspase 8 is activated by the DED domain and that activates the executioner caspases
name the type of cells which closely reside with stem cells, limiting their environment
stroma cells
Name 2 ways in which stem cells differ from other cells
They can divide to renew themselves indefinitely
* Self-renew
They can generate specialized (differentiated) cell types
* Multipotent or unipotent
The environment around them controls their activation
* Niche
how is a constant pool of stem cells maintained?
symmetric and asymmetric division
how does asymmetric cell division happen (2)
asymmetric distribution of cell fate determinant during mitosis or facing one daughter cell away from the niche (different environment
