Question

Based on cellular mechanisms there are two major types of regeneration found in the animals. Which one of the the following is the correct example of the type mentioned?

(A) Morphallaxis	Regeneration of two transversely cut equal pieces of a Hydra into two small Hydra.
(B) Epimorphosis	Replacement of old and dead erythrocytes by the new ones.
(C) Morphallaxis	Healing up of a wound in the skin.
(D) Epimorphosis	Regeneration of crushed and filtered out pieces of a Planaria into as many new planarians.

• A. (C)Morphallaxis- Healing up of a wound in the skin.
• B. (B)Epimorphosis- Replacement of old and dead erythrocytes by the new ones.
• C. (A)Morphallaxis- Regeneration of two transversely cut equal pieces of a Hydra into two small Hydra.
• D. (D)Epimorphosis- Regeneration of crushed and filtered out pieces of a Planaria into as many new planarians.

Answer 1

The correct option is C (A)Morphallaxis- Regeneration of two transversely cut equal pieces of a Hydra into two small Hydra.

Morphallaxis
Morphallaxis is the re-patterning of the existing tissue to replace the lost one.
Examples:
1. Regeneration of two transversely cut equal pieces of a Hydra into two small ones.
2. Regeneration of crushed and filtered pieces of a Planaria into many new ones.

Epimorphosis
Epimorphosis involves formation of an undifferentiated mass of tissue called blastema. These cells proliferate to restore any lost part of the body.
Example: Healing a wound in the skin, a lizard can repair its tail if it is lost.

Psychological regeneration
Physiological regeneration occurs during normal loss of cells in the body once they complete their lifespan and die and not at the time of injury. Example: Replacement of old and dead erythrocytes by the new ones.

Final answer
(a) Morphallaxis -Regeneration of two transversely cut equal pieces of a Hydra into two small Hydra.