How many layers of skin do we have? The answer might surprise you. As it turns out, the human body has three main layers – the epidermis, dermis, and subcutaneous fat layers – as well as several other sub-layers.
All of these make up the skin, which is the body’s largest organ.
Here’s a look at each one of these layers. All of them are critical to protecting your muscles and internal organs, but they also play many other important roles in keeping you healthy.
The epidermis consists of a type of tissue known as keratinized squamous epithelium. It’s the surface layer of your skin, so it’s the most recognizable. In some areas, like the eyelids, it’s very thin. In other areas, such as palms and soles, it’s thick.1
The epidermis plays many important roles. For example, it’s responsible for making new skin cells. Over time, these cells move from the bottom of the epidermis to the top.
Eventually, dead skin cells dry up and flake off.
The epidermis is also responsible for a pigment that determines the color of your skin. It produces a pigment known as melanin. People with darker skin produce melanin at a higher rate than those with lighter skin. In addition to the pigment melanin, the epidermis produces cells that help make up the immune system.2
Some cells in the epidermis are known as keratinocytes. They produce a protein, keratin, that makes skin, nails, and hair strong. These skin cells are eventually replaced by new keratinocytes produced in the deeper layers of the epidermis.3 Stem cells are also found in this layer of the skin.4
Sub-Layers Of The Epidermis
The epidermis is actually made up of several sub-layers: the stratum basale, stratum spinosum, stratum granulosum, and stratum lucidum. Here is a brief description of each.
1. Stratum basale – This is the layer of the epidermis closest to the dermis. Cells in the stratum basale connect to cells in the dermis through collagen fibers. These cells produce the keratinocytes mentioned earlier.
2. Stratum spinosum – The stratum spinosum consists of cells that act as a sort of filter. They help to keep microscopic particles and bacteria from penetrating deeper into the skin.
3. Stratum granulosum – This layer is primarily responsible for producing keratin.
4. Stratum corneum – This is the surface layer of the epidermis. This is an area of dry skin that helps keep microbes from penetrating deeper layers, much like the stratum spinosum. It also helps keep other layers of skin from drying out.5
The dermis lies just below the surface layer. You might not be able to see it, but this layer performs a lot of important functions. For example, the dermis contains eccrine sweat glands. Sweat glands are critical to keeping your body from overheating.6 Unfortunately, the dermis also produces mast cells. These are cells that can cause major illnesses.7
The dermis is also the reason that you feel things. When you feel a gentle caress of your skin or an insect bite, that’s due to the nerve endings in the dermis. Each nerve sends a signal to your brain. Some signals tell the brain that something hurts, while others tell the brain something feels good.
There are also other important roles the dermis plays. One of them is growing hair. Every root of every hair shaft on your body is located in the dermis.
All of these roots are attached to small muscles. These muscles are the reason you sometimes get goosebumps.
The dermis also contains sebaceous glands that secrete sebum, or oil. Sebaceous glands help your skin stay smooth. Tiny blood vessels known as capillaries are also found in the dermis. These blood vessels provide the blood supply the epidermis needs to stay healthy.8
Inside The Dermis
The dermis consists of two main regions: the papillary region and the reticular region.
5. The papillary region gets its name from a structure known as a dermal papilla. These structures consist of elastic fibers that eventually form ridges on the fingers of a growing fetus. These ridges turn into fingerprints. The papillary region consists of loose connective tissue made up of collagen and elastin fibers.
Collagen fibers and elastin fibers in the papillary region help keep skin hydrated.
6. The reticular region consists mainly of thicker tissue. This helps to keep the skin flexible yet strong at the same time. It also contains collagen fibers and elastin fibers.9
The Subcutaneous Fat Layer (Or Hypodermis)
7. The subcutaneous fat layer, also known as the hypodermis, is also important. It contains loose connective tissue that attaches the dermis to your bones and muscles.
This layer of subcutaneous tissue helps regulate your body temperature as well as storing fat.
This fat acts as a sort of padding, helping to protect your bones, blood vessels and muscles from being damaged.10
Skin Problems: Should You See Your Primary Doctor Or A Dermatologist?
Your skin goes through a lot every day. As a result, it is susceptible to certain issues. First-degree burns can singe the surface of the epidermis to the point that a skin graft is needed. Ultraviolet radiation from sun exposure, or UV light from a tanning bed, can lead to painful sunburns that need to be addressed.
In addition to the UV rays that can cause trouble, a condition known as atopic dermatitis can be incredibly frustrating and can often lead to nearly constant itching.
Some issues need to be addressed by your family doctor. These include skin infections or welts that seem to come from nowhere.
In other instances, a dermatologist can help with a skin problem, such as clogged sweat glands, sensitive skin or a scar you can’t get rid of. If, for instance, you get a rash that covers an extensive portion of your skin, call a dermatologist. Even if that rash is accompanied by joint pain, muscle pain, or difficulty swallowing.11
Your skin is made up of many layers, each with a specific function. Together, it protects your body in several ways. Never take your skin, or the well being of your skin, for granted.
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