Question

8. पुनरुद्भवन पर एक निबन्ध लिखिये।
Write an essay on Regeneration.​

Answer 1

Answer:

Regeneration is an excellent ability of the adult tissue to repair any damage done to the body by autotomy i.e., voluntary separation of a part of the body, and accidental injury in nature or imposed by man under experimental conditions. This may involve replacement of dead or damaged cells, healing of a wound, replacement of lost part or the regeneration of the whole organism from a piece of body. It reflects the reawakening of the developmental processes of morphogenesis and differentiation in the adult, when such processes normally cease in post-embryonic life of the organism.

This ability is almost present throughout the animal kingdom. Hence “the ability of an animal or organism to repair a wound, which partially destroys tissues of the animal’s body or the damage involving the loss of an organ or larger part of the body which may be renewed, is thus called the process of regeneration.” Trembley first discovered it in Hydra in 1740. Of all the animals, coelenterates possess the greatest ability of regeneration, being highest in the polyploidy

It is common in planarians, nemertean and annelids, but poor in mollusks, nematodes, arthropods and echinoderms. Among vertebrates, it is remarkable in urodeles, but limited in anurans, fishes and lizards and very poor in birds and mammals.

In a healthy normal adult animal, many kinds of cells need replacement after a species -specific span of time. For example, there are approximately 25 × 1012 red blood cells in the active circulation of the human adult at any time.

About one percent of these cells are replaced daily; all the red blood cells are replaced every four months. Such replacement processes are also common in skin cells, cells in the lining of the uterus, and cells in the lining of the gastro-intestinal tract, and thus on the cellular level, it is a state of dynamic equilibrium.