In each body throughout life there are processes of updating or restoring parts or organs of the body. In humans, for example, is constantly reborn o

Regeneration [totipotency]

In each body throughout life there are processes of updating or restoring parts or organs of the body. In humans, for example, is constantly reborn outer layer of skin. Birds and mammals molt, birds shed feathers and grow a new and animals change their coat. In deciduous trees fall leaves in autumn and in spring grow new. All animals and plants can heal wounds and thus to eliminate the effects of trauma, and some can even again fully “rebuild” the lost organs. All these processes, associated with the restoration of the body by the organism, are called regeneration (from Latin “regeneration” — “rebirth”, “renewal”).

The simpler the body in structure, the greater expressed the ability to regenerate. So, hydra or planaria can just easily not to restore lost organs, but also to solve the inverse problem — to revive the body from a tiny particle of the body. The same property is also inherent in many species of plants. Begonia can restore a whole plant from a piece of leaf, and rose or currants — to turn into a bush from a small cutting (shoot with two or three leaves). Taken from http://worldofschool.org

Diagram 100. Gradual regeneration of axolotl limb

Vertebrates do not have such phenomenal abilities; however, they can recover some part of the body. Fish easily regenerate fins or scales, tailed amphibians — limbs (diagram 100), and lizards — a tail. In mammals, the ability to regenerate is not lost only in tissues, in which cell division occurs constantly, — connective and epithelial. Therefore, in human regenerates the skin and the liver, the bones grow together, but to grow not that a leg, but even a new finger is not possible.

Thus, all multicellular organisms are able to regenerate — the ability to renew or restore the body after injuries. The regeneration processes occur very easy in the lower organized animals and in most plants whose somatic cells can give rise to new organisms. Higher animals, particularly vertebrates, are only able to restore some parts of the body, or to update the cells of different tissues.

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Questions:
  • What is the difference between regenerative processes of primitive and highly organized animals?