If you were asked what your body’s largest organ is, what would you guess? Your heart? Your liver? What about your lungs? Though all of these are major organs that play very important roles in your body, they are not the largest organ.
While it may seem like your skin is a thin layer (less than a millimeter thick in places), it is actually the largest organ in your body! If you could “jump out of your skin,” you would be able to spread it out to cover more than 20 square feet! It would also weigh about 7-9 pounds.
Your skin performs many duties. It offers protection from outside elements and infections, helps your body regulate its temperature, serves to rid your body of toxins and gives color to your appearance.
Your skin is composed of three layers that fulfill many important functions.
The top layer, which is visible on the outside of your body, is called the epidermis. The very top of this layer is actually dead cells, which are continually being replenished from below as younger living cells push the older cells upward. This cycle repeats about one thousand times during your life. Every 28 days, or roughly once a month, your skin receives a brand new top coat! Keratinocytes are special cells in the epidermis that produce keratin, of which your hair and nails are also mostly composed. The body also uses this protein to help strengthen your outermost layer, guarding it from damage. Langerhans cells help to protect your body from infections by “eating” and processing anything that may be seen as a danger. Your skin’s hue is determined by cells called melanocytes, which produce melanin—a substance that gives color to your skin, and also helps shield you from the harmful effects of ultraviolet radiation from the sun. Some people produce less than a normal amount of melanin, leading to a condition called albinism, which is characterized by very pale skin and almost white blond hair. Only one in 20,000 people have this condition.
Below the epidermis lies the dermis. It is mostly composed of strongly woven fibers of two proteins, collagen and elastin. Collagen acts as a sturdy building fiber, holding the layer together, while elastin allows the skin to stretch with your movements but not break or tear. This entire layer of the skin provides support and strength to the other layers. It contains many blood vessels and nerves, conveying much of the sensory experience that you feel when you touch something, while also transporting nourishment from one layer to the next. Your sweat glands, which allow your body to lower its temperature when necessary, are located in the dermis. Hair follicles are also found here, while the hair that grows from them reaches outward through the epidermis, and then even farther to the outside of your body.
The bottom layer of the skin is called the subcutaneous fat layer, mostly composed of fat cells that provide storage for nutrients. This final layer insulates the body from varying temperatures, and protects it from minor bumps and jars.
This is just a short description of some of the interesting things about your skin. Don’t stop here! Use this as a springboard for learning more about the skin, as well as all of your body’s many fascinating components!
Sources: www.britannica.com; www.kidshealth.org; www.nationalgeographic.com.