Not so long ago, yet scientists have believed that, having reached the adult state, the organisms slows down the synthesis of proteins and other organic compounds, limited to "repair" work (the healing of wounds, changing epithelium of the skin, etc.). The very first experiments with isotopic labels have shown that this is wrong. Throughout his life is a continuous replacement of old cellular structures on the newly formed. For example, when repairing aircraft replaced the engine, exhaust their resources, even though it worked flawlessly. It would seem that all my life should serve man bone. However, when the practice of medicine became the antibiotic tetracycline, doctors faced with an astonishing fact. Tetracycline is partly accumulated in the bones. Traces of treatment can be found at bone thin section in the form of a fluorescent layer.
It was found that approximately three years after antibiotic therapy, he found in the blood in very high concentrations (which sometimes leads to undesirable side effects). Location he took tetracycline, because the patient than three years and could forget that once it took? He returned to the blood of old bone tissue, which dissolves and is replaced by a new one. It is said that the nerve cells do not regenerate, do not multiply. In principle it is, but throughout life they are continually rebuilt. So a person can live all your life in one house, but during this time repeatedly to change the situation there. We can only formally assume neurons, with which we end life, the same cells, which we administered it.