For thousands of years, humans have used tattoos to communicate religious beliefs, tribal affiliations, social status, and as a permanent reminder of that drunk spring break in college. It's a large part of our culture — but it seems crazy that they actually stay on our skin permanently. (How permanent? Well, scientists found a 5,300-year-old mummy with still-visible tattoos.)
Skin is our first line of defense against foreign contaminants. It's capable of healing itself when injured, and it's constantly renewing itself by shedding old cells and growing new ones.
So how is it that a needle and some ink can have such dermatological staying power?
The reason tattoos become a permanent fixture of your skin is because the needle forces ink past the epidermis (the outer layer of skin) down to the dermis (the second layer). Because the dermis doesn't slough off cells like the epidermis, the ink doesn't wear away.
Of course, the process of shoving ink down into the dermis alerts the immune system of a threat. White blood cells swoop in to eat the foreign bodies, but the pigment molecules are just too large. When getting laser tattoo removal, the laser just blasts the pigment and makes the pieces small enough for the immune system to carry away.
Check out the full science of getting inked in the AsapTHOUGHT video below:
Got any tats? Let us know about them in the comments section!
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