Regeneration

Question 1

What is the blastema?

Answer 1

A mass of undifferentiated cells uner wound epidermis that gives rise to structures distal from cut.
Blastemal cells derived locally from mesenchymal cells.

Question 2

Desctibe the need of nerve supply in regeneration

Answer 2

Nerve produces essential growth factor - naG

Question 3

describe regeneration in Hydra

Answer 3

does not require growth,
the heads of hydra produce signal that inhibits secondary axis induction - stops inappropriate head formation
experiments in hydra suggest formation of extra heads prevented by lateral inhibition.
wnt/beta-catenin expressed at tip of hypostome and more broadly after amputation

Question 4

describe amphibian limb regenration

Answer 4

blastema formation through dedifferentiation
blastema grows to form distal structures
positional values of blastema depend on RA signalling and prod1
nerve dependent as nerve produces essential growth factor - naG