Does Our Skin Replace Itself Every 15 Years? Why do We Still have Scars and Freckles?
Another great question/answer from Peter Mansbridge and Bob McDonald on CBC!
If it is true that our skin organ replaces itself within about a 15-year period, why do I have birthmarks that have been on my skin since the beginning, or moles and pock marks or freckles and even scars from more than 15 years ago? (Terry Mooney)
It is true. You skin turns over about every 15 years and so do you bones. Each cell that replaces itself has genetic material (DNA) that contains the information which made that cell in the first place. So if the DNA says that that particular skin cell is going to be a bit darker than the others, that information is preserved. So when the cell reproduces, the cell will still be dark.
Scars are a little different. When you cut yourself and skin replaces itself, those are different types of cells because they are made from stem cells (made from scratch). They usually don’t have any pigment in them at all which is why if you sunburn a scar, they will turn pink and burn. They are specialized cells that were programmed to do this particular task and that program is passed on when the skin replenishes itself.
And how do tatoos fit in to this equation? Well, tatoos are not inside the cells, they are between the cells. Therefore, it is not part of the reproduction process. Tatoos just sit there as the cells around them change which is why they last so long.
To your health,
You Be Healthy
