Question

Epimorphosis is
(a) Degeneration of old organs
(b) Regeneration of lost body parts
(C) Regeneration of the whole body from a small portion
(d) None of the above

Answer 1

Hint: Epimorphosis is a process that is prominent in invertebrates like frog and salamander. This process progresses in a unique fashion with a cycle of dedifferentiation followed by growth and finally differentiation.

Complete answer:
Epimorphosis is a type of regeneration which is common practice in many invertebrates like frog and salamander. Here, the lost or damaged part is recovered or regenerated without any drastic configuration of the remaining undamaged part of the body. The Epimorphosis process begins with the covering of the epidermal surface of the area where the injury has occurred with an undifferentiated clump of cells known as blastema.

Additional Information: -The blastema is formed by the dedifferentiation of mature cells. The dedifferentiation regresses a mature cell into a simple state or cell just like stem cells.
-The growth of blastema is followed by its differentiation, where it develops into the part which was lost or damaged and acquires a particular function to perform as any permanent cell types.
-The other type of regeneration is known as morphallaxis where the whole body is regenerated from a small portion. The regeneration in Hydra is a well-known example of morphallaxis wherein drastic remodeling of cells takes place at the site of the wound and a new organism is regenerated with all body parts. No blastema formation occurs in morphallaxis.
-The degenerative aging process leads to the degeneration of old body parts. Some diseases like Alzheimer’s disease, muscular dystrophy also contribute to this degeneration.
So, the correct answer is ‘Regeneration of lost body parts.’

Note: -In Alzheimer’s disease, the chronic degeneration of nerve cells leads to memory deterioration as well as a steady decline in metabolism due to poor brain functioning.
-Muscular dystrophy is a progressive degenerative disease of muscles wherein a mutation in the X-chromosome leads to less or no production of dystrophin protein. The protein is essential in the building and repairing of muscles.