Your Skin: Its Structure and Many Functions

​We take special care of our skin because it's the most visible part of who we are physically. But, do you know exactly what your skin does for you? Why does collagen matter? And what happens within your skin that causes wrinkles and other changes?
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The functions of your skin

Your skin is one of the largest organs in your body.  In an average adult, it accounts for about 12 to 15 percent of total body weight and covers almost 21 square feet of surface area. Contrary to popular belief, the skin is much more than a mere water-resistant covering for the body; it is a very complex organ system with many important functions that aid in maintaining homeostasis. 

Protective roles:
To start, your skin provides your first line of defense as a barrier from harmful items in the external world. This makes it a vital part of your immune system. It protects you from variations in temperature, micro-organisms, pathogens, radiation, and chemicals. 

Regulatory roles:
Next, the skin regulates several aspects of your physiology. It controls your body temperature via sweat and hair and changes in your peripheral circulation and fluid-balance via sweat. This makes the skin an important organ of your excretory system and vital for detoxification. Your skin also acts as an endocrine organ and is necessary in the synthesis and storage of vitamin D, which is actually a hormone.  

Sensory roles:
The skin also contains an extensive network of sensory nerve cells that detect and relay changes in your environment. There are separate sensory receptors in the skin for heat, cold, touch, and pain. Additionally, the skin also has a major role in physical attraction between people and reproduction through exhibiting sex characteristics and emitting pheromones. It also matters for aesthetics and communication, because when others see our skin, they can assess our mood, physical state, health status, age, and attractiveness.

(This is also some great info to share with some curious kiddos!)

The structure of your skin

Your skin is made up of cells called epithelial cells, which not only form the skin, but also cover most internal organs and line the hollow cavities inside your body like your digestive tract. Epithelial cells are known to be the type of cell with the most rapid speed of cell division and fast-acting repair mechanisms in the human body. They grow and heal very quickly.

The skin also contains many types of specialized cells, some of which produce its five appendages:

• hair 
• nail tissue,
• sweat glands
• sebaceous (oil) glands 
• mammary glands  

Photo source: (Simon, 2013)

​Your skin is composed of two main layers.  The outer layer is the epidermis, which is a layer of tough, flat skin cells that serve a protective purpose.   The epidermal cells are four or five layers thick and move upward toward the surface, pushed by new cells below, until they flake away.   The underlying layer, the dermis, contains many tissues with varied functions.  It contains thousands of nerves for the sense of touch, as well as sweat glands, and adjustable blood vessels for temperature regulation  

Collagen and elastin are the connective tissue fibers within the dermis. They are  made from protein. Collagen fibers come in bundles and provide structure and strength to your skin. (Collagen is also found in ligaments, tendons, adipose (fat) tissue, cartilage, blood vessels, bone, the cornea of the eye.) Elastin, a different and less abundant type of protein, forms a network between the collagen fibers. Elastin helps the skin stretch and makes it resilient and spring back into place. So, if you imagine your skin was your house, the collagen would be the the intricate framework that hold it up and makes it sturdy, and the elastin would be all the flexible brackets that hold the collagen framework in place. Unfortunately, they are both quite fragile.

Glycosaminoglycans (GAGs)  are the major water-holding components of the dermis. The most commonly known GAG is  Hyaluronic acid. GAGs are vital because ample hydration prevents dry, rough skin, helps the healing process, and keeps your skin moist, soft, and full of volume. 

Together, these three components (collagen, elastin, and GAGs) are known as the extracellular matrix (ECM). It is the breakdown of the skin’s ECM that comes with aging and other changes in your overall health. When the ECM breaks down, the skin will show wrinkling, sagging, thinning, dryness, and be more susceptible to developing skin disorders. In particular, when the bundles of collagen and elastin degrade, the fibers become cross-linked, slacken, and they unravel. This reduces the skin's strength, elasticity, and support function. The formation of new collagen and the regeneration of collagen also slows with age. (To read in much further detail about how wrinkles form and what causes them, see my post HERE.)

​Under the dermis is a layer of fat called the hypodermis, which is sometimes regarded as a third layer of the skin. These fats cells provide thermal insulation for you against the heat and cold. The hypodermis also provides your body its contours.

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So, I hope enjoyed this little science lesson and that you understand how important your skin is. It certainly works in many ways to serve your body well. Plus, now you know what exactly happens to your collagen and elastin that causes wrinkles to form.

The healthier we are, the better we will age - and our skin will show it. In my next post, What Causes Your Skin to Age? The Intrinsic & Extrinsic Factors, I discuss how much control you really have over skin aging. It's a good one!!

Want to learn more?

Take my e-course about the skin & how to age gracefully:

​​Time Defying Skin discusses the causes of aging that you have control over. The keys to youthful skin and feeling healthy may not be that complicated or expensive after all. A nourishing diet and healthy lifestyle practices are the natural solution. It's never too early or too late. ​Take the course today!

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Article sources:

• CliniMed. (2014). Structure and Function of the Skin. Retrieved from http://www.clinimed.co.uk/Wound-Care/Education/Wound-Essentials/Structure-and-Function-of-the-Skin.aspx
• Pappas, A. (2015). Skin Basics; Structure and Function. In Lipids and skin health. New York: Spring Science Business Media. 
• Parker, S. (2007). The human body book. New York: DK Pub. 
• Simon, H. (2013, September 18). Skin wrinkles and blemishes. Retrieved from http://umm.edu/health/medical/reports/articles/skin-wrinkles-and-blemishes

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