Organ Series: Skin

By Christopher Theberge

Have you ever wondered what the largest organ of the human body was? Contrary to what most men believe, the answer to that question is your skin. People don’t realize that yes; your skin is an organ too. A basic definition of an organ is a structure that is made up of cells or tissue that have some specific function within an organism. In terms of performing tasks, the skin has one of the most demanding jobs of all. It provides you with a protective barrier from environmental contaminants, aids in temperature regulation, acts as a detective for infections, responds to touch and pressure, aids in Vitamin D synthesis and is important for social interactions and sexual attraction.

What Is Skin?

Your skin is made up of two layers, the epidermis (outermost layer) and the dermis (innermost layer). The epidermis grows from the bottom up. The reason that this occurs is because it works to push dead skin cells to the surface. Once on the surface, it is almost invisibly flaked off. It takes about 1.5-2.5 months for the whole process to take place, about the same amount of time it takes your partner to change that burned out light bulb in the bathroom.

The epidermis is quite fascinating. It is the reason why our bodies do not shrivel up and die. Think of the skin as a waterproof barrier. There are natural oils present within the dead skin layer that prevent water loss. Have you ever made your own salad dressing? You see two separate layers: oil and water. Water cannot penetrate the fat layer. This is essentially how the skin protects itself from water invasion and evaporation. If we were to remove the epidermis, we would lose tons of water and if we were then submerged in a pool, then we would swell up like Rush Limbaugh. The reason for this is because the dermis, unlike the epidermis, is permeable to water.

Human skin is also made up of non-hair bearing skin (Glabrous) and hair bearing skin. The soles of your feet and palms of your hand consist of the non-hair bearing skin, well for most of us.

If scientists were convinced that each skin cell were worth one dollar, humans would be extremely rich. The 7 pounds of skin that covers the average human being houses about 300 million skin cells.

Skin as a barrier

As noted above, the skin prevents excessive dehydration and “overhydration”. There are many other protective factors that the skin provides as well. For example, it protects our insides from frying when we bake in the hot sun. If we didn’t have skin, then we would have seagulls trying to pick at our cooked organs.

The skin is also essential for preventing bacterial invasions into the body. Sweat and sebum (fatty material secreted by skin glands) aid in impeding bacterial growth on the skin, which would otherwise invade the body. The skin also provides protection from physical injury. It is made up of the protein collagen, which offers great support and strength, as well as elastic fibers that give skin its flexibility. Subcutaneous fat under the skin and the epidermis layer also provide support.

Skin and Temperature Regulation

The skin acts as a heat sensor, which is very sensitive to temperature changes. The thermostat is located in the brain, particularly the hypothalamus. There are four ways that the skin releases heat: radiation, conduction, convection, and evaporation. Instead of exploring the laws of thermodynamics, I am only going to discuss evaporation.

The human body favors a temperature around 98.6 degrees Fahrenheit. When the skin starts to heat up, signals are sent to the brain to start sweating. Calm down ladies! Sweating acts to cool off the body. As water or sweat starts to build up on the surface, it is lost by evaporation, thus releasing heat to the environment. Have you ever been in a crowded room and felt really hot? The reason for this is that there is a tremendous amount of heat released by our bodies. Again, calm down ladies!

On the other hand, when the skin starts to get cold, the thermostat is turned up a notch. The body constricts blood vessels, thereby conserving heat and slowing the amount of heat to the skin. It also promotes shivering to generate heat and secretes hormones involved in heat production. The reason why the skin is less protected during cold weather is because of the high importance of your internal organs. This is one major reason why frostbite occurs.

Skin As A Vitamin Synthesizer

The skin contains a compound that is an intermediate for cholesterol synthesis known as 7-Dehydrocholesterol. This compound secreted by skin glands onto the surface of the skin, and then absorbed into the epidermis. When sunlight hits the skin, the compound is broken apart and turns into Previtamin D. From here the Previtamin D becomes activated in the body. The reason why food products have become fortified with the vitamin are because not all areas of the world support natural vitamin D conversion by the sun. Sunscreen at SPF 8 is enough to prevent vitamin D synthesis. Also, temperate regions (beyond 40 degrees North or South) have poor UV light concentrations essential for synthesis. Don’t worry about getting too much vitamin D production from the sun because the reaction is reversible. Therefore, the body stops production once it realizes that it has enough.

Skin For Social Interaction

It’s every woman’s nightmare to have wrinkled skin, or skin covered with acne. Some of the first signs of aging are changes in the skin. Overtime, the collagen and elastic fibers loosen up from natural aging, as well as from increased oxidative damage. Some examples of oxidative stress are excessive sun exposure (UV rays), smoking, and the presence of pollutants. Tanning greatly increases your risk for developing skin cancer and enhances the aging process. Although tan skin is considered beautiful, it is a short-term fix.

Acne is another problem that many women face. Acne is caused by hormonal changes, as well as clogged pores. Excessive washing of the skin with irritating astringents is not recommended. Foaming face washes are gentler on your skin than is plain soap. If you have severe acne, there are a variety of pharmaceutical products such as Differin Gel, Retin-A, Accutane, and Tetracycline available. If you don’t fall under this category, but are concerned about acne, then you may benefit from using a product that contains 2.0% Salicylic Acid.

Following a balanced diet is very important for maintaining a great complexion as well. Vitamin C is involved in collagen synthesis and Vitamin A supports cell growth and differentiation. Foods that have an ample amount of vitamin C include strawberries, oranges, broccoli, and mainly all citrus fruits. Vegetables contain B-carotene, which is a precursor to Vitamin A. Already formed vitamin A is found in liver and animal flesh. Vitamin E acts as an anti-oxidant and is crucial for the prevention of cellular death. Ingesting higher amounts of the following vitamins will not guarantee you better skin, actually it could be quite damaging. Don’t waste your hard-earned money on vitamin supplements. Instead, focus on getting the daily-recommended amount of fruits and vegetables, drinking plenty of water and exercising for at least 30 minutes every day.