A Super-human Organ

When most people think of important human organs, they don't usually think of the skin. But skin is actually the largest organ in the human body, weighing about 8 pounds (3.6 kilograms). The average adult has 22 square feet (2 square meters) of it [source: National Geographic]. With all that skin, you can see how this organ is so crucial to the body.

Skin Barrier Function

A healthy epidermis is crucial to your overall well-being. Learning how to protect skin and keep it healthy will not only make you look better, but it will also help you keep your body functioning correctly.

Your epidermis plays a key role as the protector, defender and gatekeeper of your body. Finer and thinner than plastic wrap, the epidermis performs remarkably well as a protective barrier for the human body [source: Healy].

The primary job of the skin barrier is to keep water-rich internal organs from drying out by preventing water loss in dry environments [source: Denda]. Without this protection, the body would not be able to sustain its normal activities, and everything -- from major organs down to the tiniest cells -- would dry out and die. The skin barrier also acts as a sort of dam, keeping too much water from rushing into the body. The barrier provided by the skin allows just enough water to enter the body without flooding it.

The skin barrier also works to keep other things out of the body. Think about all the elements and substances you are exposed to every day, such as chemicals, pathogens and sunlight. The human skin does a good job of blocking out all these undesirable substances and forces. And all this happens around the clock, on a level so small you can't even see it. The skin's processes are highly complex, and most of them are invisible to the naked eye.

There is one instance, however, in which you can actually see how your skin protects you. When you are exposed to excessive sun rays, the skin produces more of a pigment called melanin, which darkens your skin and helps protect the body from potentially damaging ultraviolet, or UV, rays. You see this happen when you develop a sun tan.

You may be wondering whether the skin products you see in the store and advertised in beauty magazines can help to boost the power of your skin barrier. Read on to find the answer.