Your skin is the largest organ of your body. Perhaps it is the most wonderful too. It covers your entire body like a shield and contributes a lot to your appearance. You would certainly look awful without it!
Skin is made up of two layers—the inner and the outer—and contains two special kinds of glands, a network of tiny blood vessels, and countless nerves.
When you look at the back of your hand through a magnifying glass, you can see an irregular pattern of lines running in many directions. You can also see a forest of tiny hairs growing up through the skin. Patches of small white scales are often visible too. These are areas of cells that are continually dying and falling off. These dead cells help to make the ring in the bathtub when you take a bath.
When you were a baby, your skin fit you perfectly, just as it does now. As you grow, your skin grows with you. Should you lose a little weight, your skin shrinks to fit your body. Skin is elastic. It bends and stretches when you run, jump, sit, or play. Wiggle your fingers back and forth. Bend your wrists. Flex your arms at the elbows. Tuck your legs under you when you sit. The skin on your knuckles, elbows, and knees stretches, allowing your body to move freely at these joints. Can you imagine how uncomfortable you would be if your skin lost this wonderful rubberlike characteristic? You might have to sit down and stay there!
All of your body, from the top of your head to the soles of your feet, is covered with skin. Even your eyeballs have a thin layer. The outer layer of skin, the epidermis, protects the delicate tissues of the inner layer, or dermis, from germs, excessive heat, or extreme cold.
You know what happens when you puncture your skin with a piece of metal or glass or some other object. Nerves in the skin let you feel pain. Without this sense of touch, you’d never know when you are too hot or too cold, when you have been stung by a bee or injured in any way. It’s lucky for you that the nerves in the skin alert you to these dangers.
Sometimes a wounded area on the skin gets red, sore, and hot. Germs have entered the break in the skin and have begun to grow, causing an infection. A bandage put on an injured area acts like a piece of temporary skin and keeps bacteria out while your skin underneath repairs itself.
If you tear a hole in your clothes, your mom may sew up the hole or put on a patch. If you cut your skin or scrape part of it off in a fall, you don’t usually have to worry about it being mended. Your wonderful skin automatically grows new cells to replace those lost.
A large part of the body’s blood circulates through the skin, bringing heat to the surface. On a warm day, the blood vessels of the skin expand and come closer to the skin’s surface. Because of this, heat produced inside the body can pass more easily through the skin. You are cooler when your body loses this extra heat. It could be said that you have your own built-in air-conditioning system.
On a cold day the skin does just the opposite. It contracts, or tightens, so that it is difficult for the body’s heat to pass through the skin. In this way your skin helps to insulate you from the cold so that you stay warm and comfortable.
You might think that because much of your skin is exposed to air, it will dry out. It won’t. Skin has its own built-in lubrication system. Tiny glands that produce oil are located in the dermis skin layer. A continuous flow of oil passes through tiny tubes and spills out of openings in the skin, called pores, to the outer surface. This oil keeps the skin soft and gives the hair, which is an outgrowth of the skin, a smooth, glossy look.
Another kind of gland beneath the surface of the skin is the sweat gland. Thousands of these glands collect and then release a liquid waste known as sweat or perspiration. You are always sweating a little, but on a hot day you perspire a lot, especially on your forehead, in the palms of your hands, and on the soles of your feet. This disposal system helps keep the body healthy. And as the perspiration evaporates, it also helps to keep you cool.
Would you believe that your skin helps you pick up small objects? It does! Your fingernails and toenails, which are a part of the outer layer of your skin, make it easier for you to pick up pencils, paper clips, pins, or any small object.
Do you know of anything else that is always the right size, bends with ease, warns of hurt or injury, mends itself if broken, has a built-in cooling and heating system, a disposal system, and oils itself automatically? If you do, then you know something else that is as wonderful as your wonderful skin!