Please enable JavaScript.

Coggle requires JavaScript to display documents.

L20 Stem Cells & Homeostasis (Part 1: Stem (C)s & dev (Cell Growth…

- - - - Unipotent
        
        only one potential
        
        can't prod (C)s of any other type
        
        become themselves
        
        can't become anything except eggs and sperm
      - Totipotent
        
        can become anything
        
        prod cells of any other type, including placenta
        
        when mix egg + sperm 2gth
      - Pluripotent
        
        can become most things
        
        prod all somatic cell types, but not placenta [extra-embryonic comp]
      - Multipotent
        
        prod spec somatic (C) types
        
        process of restricting the number of (C)s
        
        Germ layers & their fates
        
        Ectoderm→ CNS, epidermis, hair, mammary glands, ganglia & nerves
        
        Mesoderm → Skull, sk muscle, dermis of skin, CT, heart, bld, skeleton
        
        Endoderm → digestive tract, urinary tract, respiratory tract
      - Bipotent
        
        prod 2 (C) types
        
        can diffe into muscle or stay as stem (C)
        
        Muscle progenitor
- - - - Liver
        
        remarkable cap to regenerate (compensatory hypertrophy)
        
        Re-grow following surgical removal of 70% liver mass
        ~ remnant tissue grows to recover OG mass & function = 2wks
        ~ almost all hepatocytes re-enter S phase, proliferate & diffe. (G0)
        
        Also has tissue-spec SCs, but rarely uses them
    - - term diff.
        
        can't be made to undergo cell div
        ~ irreversible G0 arrest
        ~ if pushed? t
        riggers necrosis or apoptosis
        mitotic catastrophe = cancer protection!
        
        cell replacement must come from some other cells
      - SCs to the rescue!
        
        Most adult tissues contain tissue-spec SCs in reversible G0 (quiescence) [sits there for entire life until needed]
        ~ tissue damage (ext stimuli) → activation of SCs → undergo immense prolif → diffe. → regeneration