People think of organs as internal things - heart, liver, lungs. Your biggest organ is actually on the outside: your skin. An adult’s skin covers about 22 square feet (2 square meters) and weighs around 8 pounds - making it not only the largest organ by surface area, but one of the heaviest too.
Skin has a lot of jobs. It’s a waterproof barrier that keeps your insides in and the outside world out. It regulates your body temperature by sweating when you’re hot and constricting blood vessels when you’re cold. It senses touch, pressure, and pain. And it produces vitamin D when sunlight hits it.
Like other body tissues, skin is constantly renewing itself. Your outer skin layer completely replaces itself about every 4 weeks. You shed somewhere between 30,000 and 40,000 dead skin cells every single minute. Over a lifetime, the average person sheds around 9 pounds of skin cells - a lot of which becomes household dust. So next time you dust your room, just know: much of it is you.
