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Understanding your skin:the structure and role of the skin

Our skin, the real living envelope of our body, has a complex structure. It is home to several layers, several components and many cells, each of which has a role in the proper functioning of the skin. To treat your skin and beautify it with appropriate care, it is essential to understand its mechanisms, and the signs it sends you. Discover the structure and role of the skin with Veld's.

What is the skin made of?

The skin is a fascinating organ of the human body. It is the largest organ that our body has, not only in terms of size, but also weight, since the skin tissue represents 16% of our total weight.

On average, in a 70 kg adult male, the skin spans 1.8 m2 and weighs 3 kg. Depending on the different areas of the body, the thickness of the skin can vary from simple to double:0.6 mm on the body, 0.12 mm on the face, up to 4.7 mm on the hands and fingers. feet, 0.3 mm around the lips and eyelids.

The composition of the skin includes 70% water, 27.5% protein, 2% fat, 0.5% mineral salts and trace elements . These different components are distributed over 3 different layers of tissue:the epidermis, the dermis, the hypodermis.

Understanding your skin:what is the structure of the skin?

To fully understand the skin, it is necessary to look at its structure. More than just an envelope, the skin is made up ofthree layers of tissue with different properties :the epidermis, the dermis, and the hypodermis.

The epidermis, the surface layer

The epidermis is the superficial layer of the skin, the one that we see, the one that is "on the surface". It includes three types of cells:

  • Melanocytes:responsible for skin pigmentation and tanning, they produce melanin
  • Langherans cells:which play a major role in the immune system of the skin, by protecting us from UV rays, pollution, and external aggressions
  • Keratinocytes:cells filled with keratin and lipids.

These make up 95% of the epidermis, which is constantly being renewed. Indeed, the epidermis is itself made up of 5 small layers. Keratinocytes migrate from the lower layers to reach the surface (dead skin), before being rubbed away . This keratinocyte cycle lasts an average of 30 days, the time for the skin to renew itself.

The dermis, the middle layer

The dermis is the middle layer of the skin. It supports the epidermis, while protecting the vascular network and nerve fibers present in the hypodermis. The dermis contains many nerve endings, which make the skin sensitive to touch. It also contains a dense tissue of elastic fibers, which allow the skin to stretch and be supple.

Finally, the dermis also houses the sweat glands which produce sweat, and the sebaceous glands, responsible for the production of sebum. These glands contribute to feeding the hydrolipidic film of the skin, to protect it on the surface from all aggressions, impurities and bacteria . In order to consolidate the hydrolipidic film for healthy skin, an external boost is always welcome, which is why hydration is essential on a daily basis.

In terms of chemical composition, the dermis is made up of two types of cells that are important in the functioning of the skin:

  • Fibroblasts, cells that synthesize collagen, which provides elasticity to the skin. Over the years, the junction between the epidermis and the dermis deteriorates, which makes the skin less elastic and plays an important role in skin aging
  • Histiocytes and mast cells, cells that protect our body by playing a major role in the immune reactions of the skin.

The hypodermis

The hypodermis is the deep layer of the skin. This part of the skin fulfills several functions that are essential for the proper functioning of the body. First of all, the hypodermis is a protective layer which serves as a shock absorber between the dermis and the bones in the event of shock, but also in the event of extreme temperature. Indeed, the hypodermis acts as a thermal insulator of the body.

Then, the hypodermis plays a role in the energy available in our body, since it allows fat to be stored, thanks to adipocytes. In this sense, the hypodermis is the part of the skin that shapes our morphology throughout our lives, depending on age, nutritional status, sex , it is he who will modify our silhouette. The hypodermis is therefore above all a dense fatty tissue, crossed by many vessels and nerves, which go up to the dermis.

The different functions of the skin

Understanding the composition of the skin as well as its structure is essential for choosing the right products, the right care routines, and adopting appropriate gestures. However, it is also interesting to take stock of the different functions of the skin, to better understand the "raison d'être" of each element:

  1. The secretory function :the skin is the intermediary between our body and the outside. It has a secretory function, that is to say that it allows us to reject all the elements that could destabilize our internal balance:toxins, residues linked to taking medication, excess sebum... It fulfills this role thanks to the glands sebaceous, as well as sweat glands.
  2. Sensory function :the skin is made up of a wide variety of nerve receptors, which give the skin an important sensory function. Thus, the skin receptors respond to various stimuli, such as cold, heat, touch, pain.
  3. The protective function :this is the main function of the skin, to protect our body from all the external aggressions to which we are exposed on a daily basis. It protects us from shocks and friction, aggressive products, pollution, but also from extreme temperatures, by keeping our body at a temperature of 37 degrees thanks to perspiration. In the same way, it protects the body from certain viruses, bacteria and microbes, by stimulating certain T lymphocytes and white blood cells for a good immune defense
  4. The emotional function :it is completely unconscious for us, but the skin is a means of communication in its own right. It informs those around us about our condition, and participates in visual communication. For example, it blushes to show embarrassment, can become very white in case of illness, or dull in case of fatigue, and elements such as dark circles or imperfections can say a lot about our state of health.