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LET'S EXPLORE The human body

What is your skin for?

A magnified image of skinA magnified image of skinThe body’s largest organ is the skin. It is like a thin, protective coat that covers the whole of your body. Tough, stretchy and waterproof, skin protects the body from damage and keeps germs out. It stops you getting either too hot or too cold and blocks harmful rays in sunlight. The skin also contains millions of tiny nerve endings. These provide the body’s sense of touch.

The effect of the sun’s rays on the skinThe effect of the sun’s rays on the skin


Your outer layer of skin is called the epidermis. It is always replacing itself as the dead skin flakes are worn away. Melanin, a brown pigment, gives your skin its colour. It filters out harmful rays in sunlight. If you spend a lot of time in the sun, the skin makes more melanin, so it becomes darker. Dark-skinned people have more melanin in their skin than light-skinned people.

Skin is at its thickest, about 5 mm (0.2 inches), on the soles of the feet. It is at its thinnest, 0.5 mm (0.02 inches), on the eyelids.

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