How Our Skin Works
IN THIS ARTICLE:
- The layers of the skin
- About your dead skin cells
- How can you help your skin perform better?
- Final words
Did you know, the skin is actually the largest organ of the body?
Yup. That’s right!
With all of its associated organs and derivatives (including hair, nails, glands and specialized nerve endings) our skin is an incredibly sophisticated system. Primarily, our skin serves as a protective layer against heat, light and foreign pathogens. It also helps to keep our internal organs in place.
However, all this information is only skin deep. There’s way more to our skin than meets the eye.
So, let's learn more about our skin!
First and foremost, our skin is truly diverse. We all have different skin types, such as oily, dry, combination, acne-prone and sensitive. But even if two people have the same skin type, their skin can behave differently from each other. That’s because your general skin type is just one aspect of your skin.
While the anatomy of the skin is the same from person to person, the thickness, texture and colour vary. For example, an African person tends to have a darker complexion compared to a Caucasian person who tends to have pale skin. Those variances aren’t just from person to person, but also from one area of the body to another. The skin on your eyelids is thinner and more delicate than the skin on the soles of your feet, which is thicker and more durable.
Even though everybody’s skin is unique, we all have two types of skin on our body:(1)
- Thin and hairy, which is more prevalent in areas of the body like arms, legs, torso, back, etc.
- Thick and hairless, which covers the palms of our hands and the soles of our feet, as these areas require more protection.
Regardless of any skin type, all skin contains specialized cells and structures, which work in their own ways to contribute to the complex system that is our skin.
The layers of the skinOur skin is made up of three main layers. Each layer serves a particular purpose and varies in thickness and strength. These three layers are the epidermis, the dermis and the hypodermis.(1)(2)
1. The epidermis
This is the outer layer that acts as a protective barrier from the environment. Depending on the area of the body, its thickness varies. On the eyelids, the epidermis is only about 0.05mm thick. On the palms and soles of our feet, it’s about 1.5mm thick.(1)(2)
However, the epidermis isn’t just one layer of skin. In fact, it’s made up of five other layers. From bottom to top, these layers are:
The Basal Cell Layer (AKA: The Stratum Germinativum): This layer is the deepest layer of the epidermis. It borders the dermis (keep reading to learn more about the dermis) and contains basal cells (hence the name) that continuously divide and create new skin cells. These new, younger cells push the older cells upwards. They eventually reach the surface of the skin where they become what’s known as dead skin cells and naturally shed from the body.(1)(2)
This layer is also where sensory-inducing Merkel cells and the melanin-producing melanocytes reside.(1) Melanin gives the skin its pigment. The amount of melanin produced varies, which is why different people have different complexions. However, melanin can also be induced as a response to sun exposure.
The Squamous Cell Layer (AKA: The Stratum Spinosum or The Spiny Layer): This layer is located just above the basal layer. It contains dendritic cells,(3) which are responsible for the initiation of the adaptive immune system.(4) It also contains the basal cells that have been pushed upward. These basal cells are now older and have a new name: the keratinocytes.(1)(2)
The Stratum Granulosum (AKA: The Granular Layer): This layer contains the more mature version of the keratinocytes from the squamous cell layer as they move upward. At this stage, the keratinocytes are bigger, flatter and are glued together by chemicals called glycolipids.(5)
The Stratum Corneum (AKA: The Cornified Layer): Being the outermost layer of the epidermis, the stratum corneum is made up entirely of dead keratinocytes (AKA: dead skin cells). These dead skin cells shed naturally, as they are continuously replaced by the keratinocytes from the lower layers pushing upward.(1)(2)
In addition to these sublayers of the epidermis, there’s one other thin layer called the Stratum Lucidum. This layer only exists in the thick and hairless skin type. Its main function is to protect the skin against damage as it comes in contact with other things.(5)
2. The dermis
This layer lies just beneath the epidermis. It helps to control body temperature and provides the epidermis with blood. Fun fact: The dermis stores a significant amount of our body’s water supply.(1)(2)
Similar to the epidermis, there are two layers that comprise the dermis.
The Papillary Layer: This is the upper layer of the dermis. Its main purpose is to provide nutrients to the epidermis and regulate temperature. It does these tasks by using a vascular system that circulates blood and transports substances like nutrients, oxygen and hormones to and from the cells in the body. This layer also contains thin collagen fibres.(1)(2)
The Reticular Layer: This is the lower layer of the dermis and is made up of thick collagen fibres. Its role is to provide structure and elasticity to the skin and support hair follicles, sweat glands and sebaceous glands.(1)(2)
Of course, that’s only a brief overview of the dermis. It is an extremely complex network of blood vessels, lymph vessels, hair follicles, sweat glands, sebaceous glands, nerve endings, collagen and elastin.
Speaking of collagen and elastin, as you may know, these are two important proteins that give your skin strength, resilience, flexibility and keep it looking smooth, supple and youthful.
Since collagen helps to make your skin look good, you should apply collagen onto your face, right?
Collagen itself is a huge molecule. And that means if you apply it topically, it’s unable to penetrate all the way to the dermis. At best, topical collagen serves as a humectant to draw in more hydration for your skin (which is also helpful, but in a different way).
While it’s not possible to replenish the collagen in your skin with a topical skincare product, it is possible to help your skin synthesize more collagen. You can do this with a retinoid. A retinoid is a form of vitamin A that can stimulate collagen production and promote cellular turnover.
Oh, and speaking of Fullmoon Serum, we’ve also formulated it with mahogany bark extract, a protein-rich, plant-based collagen alternative. So if you’re looking to help your skin age better, this is another reason to try this serum.
Now, onto the third layer of the skin.
3. The hypodermis
This layer is also known as the subcutis, which is basically a fatty layer of subcutaneous tissue located underneath the epidermis and dermis. Because fat is distributed differently in different areas of the body, the thickness of the hypodermis also varies from area to area and from person to person.(1)(2)
However, it isn’t just a network of fat that serves as energy for the body. The hypodermis acts as an insulator, helping the body conserve heat. It also prevents some level of injury and protects our inner organs by absorbing shock. This layer also contains blood vessels, nerves, lymph vessels and hair follicles.(1)(2)
About your dead skin cells
As I mentioned earlier, the stratum corneum is composed of dead skin cells. Now, let's unpack that a little bit more.
To begin with, the term dead skin cells is not entirely accurate.
That's because the word dead may lead people to believe that these skin cells no longer serve a purpose and we should get rid of them. This can result in over-exfoliation, thus damaging the skin barrier.
Are you confused? Don’t be. I’ll explain it all.
Let’s go back to what we know about the epidermis.
We know that the epidermis has five layers. In total, these five layers are approximately 0.05-0.1mm in thickness, depending on the area of the body. About 80% of the epidermis is composed of tightly-packed cells called keratinocytes.(2)
To quickly recap: the basal cell layer of the epidermis contains tiny round-shaped basal cells. These cells become keratinocytes as they migrate upward, through the different sublayers of the epidermis, to the surface of the skin. It takes about 14 days for these keratinocytes to reach the stratum corneum, and about another 14 days for them to naturally shed from the skin’s surface.(2) So basically, it takes about 28 days for your cells to completely turnover.
Fun fact: The dust in your home is composed of about 50% skin cells that shed naturally.
Once these keratinocytes reach the stratum corneum, they are called corneocytes. At this stage, they’re technically dead since they’ve lost their nucleus.(2)
However, just because they’re dead doesn’t mean they’re useless. They actually make up the skin barrier’s brick and mortar formation, which we’ve discussed here. The bricks in this case are corneocytes. Between these bricks are gaps filled with a mortar made up of cholesterol, free fatty acids and ceramides. Rivets called corneo-desmosomes hold this structure together and naturally loosen to allow your dead skin cells to shed on a daily basis.
That’s how the skin barrier is formed and without a properly functional skin barrier, you’re in for trouble. The skin barrier is carefully crafted to help the skin retain hydration, block out foreign substances and environmental stressors, modulate your immune system and fight off oxidative stress.
So what exactly am I trying to say?
Stop. Exfoliating. So. Damn. Much!
Remember, your skin naturally exfoliates itself after about a month. Plus, your dead skin cells serve a purpose. At Graydon Skincare, we’re all about gentle exfoliation. In fact, our sustainable Bamboo Charcoal Sponge does an excellent job of it.
How can you help your skin perform better?
Start with a balanced diet and healthy exercise regimen. This helps keep your body happy and healthy from the inside out.
Next, I encourage everyone to develop healthy skincare habits. Luckily, you really don’t need a complicated skincare routine. Try the following three step routine:
1. Cleanser. Proper cleansing removes impurities such as sebum, dirt and makeup from your skin so you don’t end up with clogged pores and a dull complexion. Click here to read our extensive guide to facial cleansing.
2. Moisturizer. It may take some time to find one that suits your skin’s needs, but it’s a worthwhile journey. The proper moisturizer will help nourish your skin and prevent dehydration. Our line of moisturizers includes Berry Rich, Skin Stuff, Phyto Clear and Putty and offers something for every skin type.
3. Sun protection. This goes beyond slathering on a non-nano, reef-safe, SPF certified sunscreen. It’s also important to avoid direct sunlight, seek out shade whenever possible, and wear protective clothing whenever you step outside!
So there you have it!
Even though our skin may look different from one another, at a cellular level, it's all the same. No matter the colour, texture or skin type, we all have an epidermis, dermis and hypodermis.
Our skin is an extremely important organ and it deserves all the love in the world. Take care of your skin and it will take care of you!
Wishing you good skin days, every day.
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Patch testing is an important part of introducing new products into your skincare routine. Click here to learn why you should never skip the patch test.
Credit for main image: svetikd
Credit for skin layers image: Science Photo Library
(1) SEER Training Modules, Layers of the Skin. U. S. National Institutes of Health, National Cancer Institute. 19 Aug, 2021. https://training.seer.cancer.gov/melanoma/anatomy/layers.html
(2) Kolarsick, Paul A. J. BS; Kolarsick, Maria Ann MSN, ARHP-C; Goodwin, Carolyn APRN-BC, FNP Anatomy and Physiology of the Skin, Journal of the Dermatology Nurses' Association: July 2011 - Volume 3 - Issue 4 - p 203-213 doi: 10.1097/JDN.0b013e3182274a98
(3) Yousef H, Alhajj M, Sharma S. Anatomy, Skin (Integument), Epidermis. [Updated 2021 Jul 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470464/
(4) Dendritic Cells. British Society for Immunology. https://www.immunology.org/public-information/bitesized-immunology/cells/dendritic-cells
(5) Shaikh, Jasmine. “The 7 Most Important Layers of Your Skin.” MedicineNet, 09 02 2020, https://www.medicinenet.com/the_7_most_important_layers_of_your_skin/article.htm