The seven layers of the skin
We spend a lot of time looking after our skin. Some days it is happy and thanks us for all the hard work by looking great. On other days, it is moody and angry and does not look its best. It seems to have a mind of its own.
Besides helping us look a certain way, did you know that the skin plays an important role in keeping you healthy? It is the largest organ in your body. It is the body’s first point of contact with the outside world. It also keeps your body protected from the outside - from bacteria, from UV radiation. It helps maintain body temperature of around 37°C and prevents water loss from the body. The body is approximately 60% water.
Even though it looks like a flat thin sheet of covering, it is more than that. The skin has many layers and is made up of different materials. How many layers does your skin have?
The layers of the skin
The skin has three main layers. The first layer is called the epidermis. It is the outer layer that you see. The second layer beneath the epidermis is the dermis. The next layer is subcutaneous tissue made up of fat.
The epidermis is primarily made up of keratinocytes cell. They contain proteins called keratin. Keratin is also found in nails and hair.
The second type of cell found in the epidermis is called melanocytes. Melanocytes makes the melanin pigment that gives skin its colour and provides protection from the sun. Regardless of skin colour, everyone has the same number of melanocytes. Dark skin melanocytes produce more melanin.
Langerhans, another type of cells, defend the body against bacteria and other harmful substances. The last type of cells found in the epidermis is the merkel cells. They provide the sense of touch. They are located in areas where the sense of touch is greatest such as the fingertips and face/lips.
How many layers does the epidermis have?
The epidermis covers almost all of the body. Its thickness varies depending on its location on the body. For example, the epidermis is thinnest on the eyelids and thickest on the palms and soles of the feet.
The epidermis is subdivided into four to five layers depending on its thickness. The palms and soles of the feet have five layers. What are the 5 layers of the Epidermis?
The five layers of the Epidermis
This is the inner most layer. It contains the keratinocyte stem cells that continuously multiple and create new keratinocytes. The older keratinocytes are pushed into the upper layer of the epidermis by newer ones. As the cells move upwards, they are filled with keratin protein and die off so that newly formed cells can move through the layers.
In this layer keratin proteins and lipids are being formed. The keratin fill the cells and the lipids help in providing a water resistance barrier.
The cells are also completely filled with keratin and start to die off because they no longer have access to nutrients and oxygen supplied from the dermal layer of the skin.
This transparent layer contains dead keratinocytes and is found only in the soles and the palms.
This is the layer of the epidermis that you see as your skin. This is also where the dead keratinocytes act as a protective barrier that keeps water from leaving the body and harmful substances from entering the body. This is also where the dead keratinocytes shed/fall off the skin unnoticed.
The dermis is thicker than the epidermis. Unlike the epidermis, it contains collagen and elastin, which provides strength and elasticity. It also contains blood, blood vessels, nerve endings, hair follicles, sweat and sebaceous glands.
There are two layers within the dermis. The papillary layer is made up of loose connective tissue and elastic fibres. It has blood capillaries and nerve endings. It also contains dermal papillae that extend into the epidermis. The blood capillaries provide nutrients and oxygens to the epidermal cells through the papillea. As the keratinocytes cells move towards the surface of the skin (up through the five layers of the epidermis), they can no longer access the supply of oxygen and nutrients, and, therefore die off.
The second inner dermal layer, the reticular layer, is made of tightly packed connective tissue and fibres. Fat tissue, nerves, hair follicle, sweat and sebaceous glands are found in between the fibres. It is connected to muscle and bones through the subcutaneous layer.
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