Your Tattoo is INSIDE Your Immune System. Literally

Summary

When you get a tattoo, the needle violently pierces your skin, killing cells and letting in ink and bacteria. Your immune system rushes to the site, but can't break down the ink particles. So macrophages surround the particles, permanently trapping them in place to protect your body, which is why tattoos last. Over time, some ink escapes and spreads or fades. Laser removal also breaks particles apart, but new macrophages quickly take their place. Your lasting tattoo is a visible tribute to your immune system constantly working to protect you.

Takeaways

• 😲 Your skin is like a conveyor belt constantly shedding dead cells from the outside in
• 🩹 Tattoo ink particles get trapped inside immune cells called macrophages
• 🔬 Macrophages try to destroy the ink but can't, so they isolate it
• 🎨 Your tattoo fades over time as some ink escapes the macrophages
• 💉 Laser removal breaks up the particles, but new macrophages rush in
• ❤️ Your immune system fights to keep the ink in place because it loves you
• 🔎 Understanding your body requires exploring science interactively
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• ✏️ Brilliant gives you tools to grasp how everything scientific fits together
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Q & A

What is the conveyor belt of death in relation to skin?

The conveyor belt of death refers to the top layers of skin that are constantly being shed and replaced by new skin cells moving up from below. These top layers are mostly dead cells that form a protective barrier.

Why can't macrophages break down tattoo ink?

Tattoo ink particles are made of heavy metals and other substances that are too large and inert for macrophages to break down with acids and chemicals. The immune system has to admit defeat and instead works to trap the particles in place.

What happens to tattoo ink over time?

Over time some tattoo ink escapes from dying macrophages. Most is recaptured but not always in the exact same place, leading to fading and blurring of the tattoo.

How does removing a tattoo work?

Tattoo removal uses lasers to heat up and break tattoo ink particles into smaller pieces that can then be carried away by fluids. But new macrophages also rush in to trap any remaining particles.

Why should tattoo ink not be poisonous?

If tattoo ink spreads through the body it can be poisonous over time. So tattoo ink should use non-toxic and non-carcinogenic pigments as much as possible.

How does the immune system react to getting a tattoo?

Getting a tattoo triggers inflammation, swelling, and a massive immune response as macrophages rush to the site to contain foreign material and ink.

What role do macrophages play in tattoos?

Macrophages are unable to break down tattoo ink so they surround and contain the particles, holding them in place forever inside the skin.

Why do tattoos fade over time?

As old macrophages die some tattoo ink particles escape and spread through the body. Most are recaptured but not always in the exact same spot, leading to fading.

How deep into skin do tattoos go?

Tattoo ink has to penetrate deep into the dermis level below the dead outer skin layers in order to remain permanent.

How does skin protect the body?

Skin protects the body by constantly shedding its outermost layers which traps debris and bacteria that can then be safely discarded.