Flashcards in Devo Lect 16 - Regeneration Deck (15)
Which animals can regenerate body parts?
Simpler organisms are the best, hydra, flatworms etc; some crabs and insects can regenerate limbs; mammals and birds hardly at all
What are the 4 types of regeneration?
Stem cell mediated regeneration (normal), morphallaxis, epimorphosis, compensatory regeneration
Regeneration vs healing
Compare muscle and liver. Muscle doesn’t have significant regeneration (fibrotic scar), but liver can fully regrow.
Stem cell mediated regeneration
Ex. blood stem cells, constantly regeneration; natural, not high level; also skin, depends on amount of damage (stem cells can die, can’t grow that fast)
Hydra and planaria; can form two organisms from two halves; have neoblasts
Used in morphallaxis; Undifferentiated cells spread throughout organism, no apparent function except in wound, migrate to wound site, reform parts of body, totipotent, only need a few
Stem cells need but not present right away; dedifferentiation
Develops after initial wound healing; cells turn off differentiated genes and become dedifferentiated, start to grow out and redifferentiate
Are blastema cells pluripotent or multipotent?
Chimera study with GFP in cartilage; gave rise to only GFP+ muscle; cells had a “memory” of what they were, therefore multipotent
Happens in mammalian liver; mostly hepatocytes, proliferate quickly (not normally dividing much)
Live liver donor
You can donate 55-70% of your liver and it will grow back in both people in a few months
In response to damage (overworked, heart attack); in humans, cells grow bigger to compensate for dying cells but not as good; scarring occurs if cut too
Zebrafish heart regeneration
First undergoes wound formation, then proliferation, then wound healing; more so compensatory, no blastema formation!
Bromodioxy uridine; Analog of uracil, incorporated into cells during S phase, shows that cells are dividing