If our body cells are replaced, why do we age? © Getty Images

If our body cells are replaced, why do we age?

Most cells in our bodies divide and are replaced when they die, but we can't rely on this process forever, especially when our DNA is setting the timer.

Asked by: Anonymous

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The cells in our bodies live for anything from a few hours, in the case of certain types of white blood cells, to a few weeks, for skin cells, to many decades, in the case of most brain cells. But while most cells are regenerated, the processes involved become progressively unreliable over time. In particular, the DNA carrying the instructions for cell processes becomes damaged, eventually preventing any more cell division. The result is the increasing level of decrepitude we call ageing.


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