Regeneration of Planarian in  Stimulants     |   home
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Regeneration
    In contrast to higher vertebrates, free living flatworms such as planaria show a fascinating ability of regeneration. Cut off its head and it grows a new one. Divide its head laterally into two, three or more parts and a two, three or multi headed worm will result. Worms can be cut into ten parts and ten complete smaller worms grow, one from each fragment. Although biologists have studied planarian regeneration for about a century, the answers to some questions, especially the molecular mechanisms governing the regeneration process still remain unknown. Scientists agree that Planaria capable of regeneration maintain and utilize a reservoir of embryonic stem cells called neoblasts. Depending upon the species, neoblasts make up to 30% of the total number of cells in an adult worm. Then, a combination of cell migration and cell division leads to an exponentially growing aggregate of regenerating cells underlying the epithelium. This structure is called blastem.Regeneration can be quite rapid. This site relates to our topic because it has to do with the regeneration of planarian.

    In biology, regeneration refers to the process by which plants and animals replace lost or damaged parts by growing them anew. Animals can regenerate their limbs, tails, or even parts of internal organs, such as the liver. Regeneration can be a response to traumatic injury, part of an animal's defense against predators, or part of a seasonal event, as when birds molt or deer replace their antlers. It seems that when an injury occurs to a structure, nerves supplying that part must be present to stimulate regrowth. The organism does not need to lose the body part completely. There are three types of animal regeneration: autotomy, compensatory hypertrophy, and metaplasia. Autonomy is the spontaneous loss and replacement of a body part. Compensatory hypertrophy occurs when tissues left on an organism after an injury grows larger to overcome the handicap caused by the loss.    
     In metaplasia, portions of the tissues adapted to one function are changed to reactivate the function of the lost structure.
    
This research on regeneration relates to our project because we are studying the regeneration of planarian.