Devo Lect 16 - Regeneration

Question 2

Which animals can regenerate body parts?

Answer 2

Simpler organisms are the best, hydra, flatworms etc; some crabs and insects can regenerate limbs; mammals and birds hardly at all

Question 3

What are the 4 types of regeneration?

Answer 3

Stem cell mediated regeneration (normal), morphallaxis, epimorphosis, compensatory regeneration

Question 4

Regeneration vs healing

Answer 4

Compare muscle and liver. Muscle doesn’t have significant regeneration (fibrotic scar), but liver can fully regrow.

Question 5

Stem cell mediated regeneration

Answer 5

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)

Question 6

Morphallaxis

Answer 6

Hydra and planaria; can form two organisms from two halves; have neoblasts

Question 7

Neoblasts

Answer 7

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

Question 8

Epimorphosis

Answer 8

Stem cells need but not present right away; dedifferentiation

Question 9

Blastema

Answer 9

Develops after initial wound healing; cells turn off differentiated genes and become dedifferentiated, start to grow out and redifferentiate

Question 10

Are blastema cells pluripotent or multipotent?

Answer 10

Chimera study with GFP in cartilage; gave rise to only GFP+ muscle; cells had a “memory” of what they were, therefore multipotent

Question 11

Compensatory Regeneration

Answer 11

Happens in mammalian liver; mostly hepatocytes, proliferate quickly (not normally dividing much)

Question 12

Live liver donor

Answer 12

You can donate 55-70% of your liver and it will grow back in both people in a few months

Question 13

Heart regeneration

Answer 13

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

Question 14

Zebrafish heart regeneration

Answer 14

First undergoes wound formation, then proliferation, then wound healing; more so compensatory, no blastema formation!

Question 15

BrdU

Answer 15

Bromodioxy uridine; Analog of uracil, incorporated into cells during S phase, shows that cells are dividing

Question 16

How can we stimulate regeneration of human heart?

Answer 16

Need to get cells to proliferate (GFs and receptors)