T


he sun burns it. T e wind chaps


it. You scratch, scrape, and bruise it. Your skin takes a lot of abuse. Yet that’s all part of its job. Your skin is like a suit of armor. It


isn’t hard and shiny. Yet it protects your body. It keeps your body at the same temperature. It lets you feel what you touch. People aren’t the only ones with skin. Animals have it, too. Let’s explore skin from the outside in.


A Tough Outer Layer Skin is an organ made of diff erent layers. An organ is a part of your body that has a job to do. Each layer of skin protects you in diff erent ways. T e top layer is the epidermis. It’s


made of cells. A cell is the smallest part of a plant or animal. Under a microscope, epidermis cells look like fl attened corn fl akes. T ese cells are thickest on the


soles of your feet. Your feet need a tough covering. T e epidermis is tough. Yet in some places, it can be as thin as a sheet of paper. Compare your skin to the skin of a rhinoceros. A rhino’s skin is as thick as a dictionary!


18 NATIONAL GEOGRAPHIC EXPLORER hypodermis


Dead Cells Now here’s something interesting. All the cells that make up your outer skin are dead. Yet you couldn’t live without them. T ey block out water, dust, chemicals, and germs. So these harmful things can’t get inside your body. T ey protect you from the sun. T ey protect you from hard blows. Dead skin cells drop off quickly.


Run your hand over your arm. You just brushed away about a thousand dead skin cells.


epidermis dermis


This close-up photo of skin shows three layers of skin.


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