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It’s a simple question but, surprisingly, many of us don’t fully understand the function of our skin. The good news is that we all seem to be really interested in skin right now. Thanks to the global pandemic caused by COVID-19, many Americans have been flocking to skin care as a form of self-care during this unprecedented times. So now is the perfect time to learn how your skin works.

You may not realize it but our skin is the human body’s largest organ. It also serves as the primary protective barrier to our bodies. Other functions of the skin include regulating body temperature and detecting and relaying changes in our environments AKA sensation.

Our skin is also like an ecosystem. There are thousands of microorganisms all over us which includes mites, bacteria, fungi, viruses. Most of the microorganisms are quite harmless and, in fact, recent research finds them to be quite beneficial—some even help provide crucial functions of the skin!

So, as you can imagine, taking care of our skin is kind of a big deal. Of course, when we are doing our daily grooming routines, we think nothing about this. We just want to look good! But it’s important for us to understand how the skin functions so that we can make more informed decisions when purchasing products to help us maintain it.

The Three Layers of the Skin

There are three layers to the human skin: epidermis, dermis, and hypodermis (subcutaneous tissue). The epidermis is the outermost layer of the skin and contains five sublayers within it. No blood vessels exist within the epidermis and this layer is primarily made up of keratinocytes, melanocytes, Langerhans cells, and Merkel cells. The former three play a major role in your skin’s appearance.

Keratinocytes primary function in the skin is to provide a protective barrier and help fight against environmental risks like UV damage, dehydration and extreme heat. Melanocytes are the cells responsible for providing our melanin, which gives us our skin color. The main purpose of the Langerhans cells is to help fight off skin infections. These cytes and cells also come into contact with everything you put onto your body. Which is why it’s a bit misleading when some clean beauty marketers claim that other products are “harmful to the skin”.

Our skin’s elasticity and resilience is created in the dermis. The dermis is composed of collagen, elastin, and extra fibrillar matrix (a mix of glycosaminosglycans and hyaluronic acid) and contains two sublayers: the papillary layer and the reticular layer. The hypodermis contains subcutaneous fat and adipose tissue. In short, this is where our body stores fat. The “meat” on our bones lives here. I won’t be talking much about the dermis and beyond as that is not within my scope of practice.

When discussing how your skin works or how it may work with certain products, practitioners are almost always referring to the epidermis and dermis.

Other Important Things in/on Our Skin

The hair on our bodies also affects the appearance of our skin. The primary function of hair on our bodies is to provide protection from environmental dangers, thermoregulation, and sensory input. Our hair traps harmful materials from entering our bodies via the eyes, nose, and ears; alerts us to foreign invaders like insects, helps us manage sweat and body temperature, and even gives us goosebumps. “Goosebumps” happen when the arrector pili muscles connected to each hair root contracts in response to nerve signals. It’s not technically any bumps but your hair raising.

And then there were sebaceous glands. Sebaceous glands are what makes us waterproof but, for some of us, can also be the root cause of our skin care woes. An oil gland found all over the body, sebaceous glands generate and excrete sebum (oil), lubricate the skin and help make the skin pliable. We have the highest concentration of sebaceous glands on our face and scalp and none on the palms of our hands and soles of our feet. Though they are present on our bodies from birth, they are activated by hormones that we don’t get until puberty hits. 

Lastly, pores are the openings to our hair follicles and glands. Sometimes you may hear skin care professionals refer to a pore and a follicle interchangeably, both terms are correct. The purpose of pores is to allow the skin to properly sweat and release oil as needed to lubricate the skin. 

All of these factors and functions are fundamental to understanding how your skin works. So now that you’ve gotten a brief scientific breakdown, are you taking good care of your skin?