Like most things in nature, our skin has several layers. Each layer has a function that is vital to the protection, care, and enjoyment of humans. As your largest organ, we put a lot of emphasis on taking care of it; From spa days, to daily moisturizing and exfoliating, humans have found many ways to take care of the appearance of their skin. But how does the skin take care of us?
To answer that question, let's go through the layers of the skin and give some respect to this mighty organ.
The Hypodermis: Your hypodermis is the innermost layer of your skin. It is primarily composed of adipose cells (fat containing cells) and fibrous tissue. Because of its composure, the hypodermis acts as an insulator, keeping heat within your body, as well as a trauma barrier. Because adipose cells are largely composed of resilient fatty tissue, the hypodermis is able to help absorb impact from exterior trauma. Think of how it hurts less to fall on your bum than it does your elbow. These adipose cells can also work as energy storage units, and this energy can be used for bodily function.
The middle layer of your skin is called the dermis. This beautiful layer of skin contains several smaller functional units such as sweat glands, hair follicles, oil glands, and blood vessels. Sweat glands permeate through the dermis to the outer layers of the epidermis (outermost skin) and release *you guessed it* sweat! Sweat has a number of properties, but for now thermal cooling is the main one we will mention. The base of hair follicles can also be found in this middle layer. Hair is found on nearly every inch of our skin, and it works alongside the skin as protection from UV rays, to produce warmth, and create a protective barrier against some pathogens. Attached to the hair follicle is oil glands. These glands produce an oil that is sent up along with the hair. Once to the surface, the oil acts as protection for the hair and can spread out along the skin as a hydrophobic barrier (meaning your skin will repel water at this layer). Lastly, blood vessels can be found in the dermis. In regards to skin, the blood vessels bring nutrients to the skin that are required for the skin cell’s health and reproduction. Additionally, they take away nutrients that have been created by the skin such as Vitamin D. The blood vessels in the skin act as a regulator for temperature. They will dilate to allow greater blood flow and warmth or contract to restrict blood flow. Nerves run through the dermis and have their nerve endings in the epidermis. Nerves in the skin react to numerous stimuli and work to protect you. For example, these nerves are how you know you’ve cut your finger or that you need to remove your hand from a hot stove.
The outermost layer of skin is called the epidermis. This is the layer of which you can see the top most part. This layer varies in thickness depending on the location on the body. This is where the sweat glands open into to release the sweat which allows your body to cool itself. Not only can sweat cool you, it also contains waste products and salt that your body needs to excrete. Bacteria, yeast, and pathogens can also be found on this layer. Your skin always has some form of bacteria on it, but don’t worry! Most of the bacteria is working in a symbiotic relationship with you. Your skin gives it an environment to live on, and in exchange it battles harmful pathogens for you or takes up space that would otherwise be taken by harmful substances or pathogens. This layer is one that you’d primarily think of for physical protection. The epidermis is a multilayered cellular entity. Meaning that there are many many layers of cells within this layer of skin. As you go about your day, your skin sloughs off and then the next layer is pushed up. As this occurs, bacteria (both harmful and helpful) is also sloughed off. As you go about your life in the outside world, your skin’s bacteria is replenished. Additionally, the thickness of this layer allows for some abrasion protection such as cuts, scrapes, or burns. Your epidermis is incredibly intelligent as well. When it is exposed to the sun, your skin cells release melanin. Melanin is a bodily chemical that provides protection from UV rays from the sun. It is also pigmented so it changes the color of the skin cells (that is why you look tan). As your body reacts to the UV rays and creates melanin, there is a secondary chemical reaction occuring that synthesizes Vitamin D. Vitamin D has a plethora of benefits including prevention of cancer, heart disease, and osteoporosis. Vitamin D is also a hormone reactor and can improve your mood!
Overall, your skin is an amazing multilayered organ with numerous forms of protection for you. By using bacteria, density, melanin, fatty tissue, blood vessels, and more, your body is well equipped to take on the world!