Our skin, a true 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 heal your skin and beautify it with appropriate care, it is essential to understand its mechanisms, and the signs it addresses you.
Understanding beauty care guide made simple
The skin is an organ of the human body quite fascinating. It is the largest organ in our body, not only in terms of size but also weight since the skin tissue represents 16% of our total weight.
On average, in an adult man of 70 kg, the skin extends over 1, 8 m2 and weighs 3 kg. According to the different areas of the body, the thickness of the skin can vary from single to double: 0, 6 mm on the body, 0, 12 mm on the face, to go up to 4, 7 mm on the hands and feet, at 0, 3 mm around the lips and eyelids.
The composition of the skin comprises 70% water, 27.5% protein, 2% fat, 0.5% mineral salts and trace elements. These different components are distributed over 3 layers of different tissues: the epidermis, the dermis, the hypodermis.
Understanding your skin: what is the structure of the skin?
To understand the skin, it is necessary to look at its structure. More than just an envelope, the skin consists of three layers of tissues 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 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
- Langerhans cells: which play a major role in the immune system of the skin, protecting us from UV, pollution and external aggression
- Keratinocytes: cells filled with keratin and lipids.
These make up 95% of the epidermis, which is in constant renewal. Indeed, the epidermis itself consists of 5 small layers. Keratinocytes migrate from the lower layers to the surface (dead skin), before being eliminated by rubbing. This keratinocyte cycle lasts on average 30 days, the time that the skin is renewed.
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 fabric of elastic fibers, which allow the skin to stretch and be supple.
Finally, the dermis also houses sweat glands that produce sweat, and sebaceous glands, responsible for the production of sebum. These glands contribute to nourishing the hydrolipidic film of the skin, to protect it on the surface of 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 in everyday life.
On the chemical composition side, the dermis consists of two types of cells important in the functioning of the skin:
- Fibroblasts, cells that synthesize collagen, which brings elasticity to the skin. Over the years, the junction between the epidermis and the dermis deteriorates, making 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 is the deep layer of the skin. This part of the skin fulfills several functions essential to the proper functioning of the body. First, the hypodermis is a protective layer that serves as a buffer between the dermis and the bones in case of shock, but also in case 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 to store the fat, thanks to the adipocytes. In this sense, the hypodermis is the part of the skin that shapes our morphology throughout our life, according to age, nutritional status, sex, it is he who will change our silhouette. The hypodermis is above all a dense adipose tissue, crossed by many vessels and nerves, which go back to the dermis.
The different functions of the skin
Understanding the composition of the skin and 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:
- Secretory function: the skin is the intermediary between our body and the outside. It has a secretory function, that is to say, it allows to reject all the elements that could destabilize our internal balance: toxins, residues related to the taking of drugs, excess of sebum … It fulfills this role thanks to the glands sebaceous, as well as sweat glands.
- Sensory function: The skin consists of a wide variety of nerve receptors, which give the skin an important sensory function. Thus, skin receptors respond to a variety of stimuli, such as cold, heat, touch, and pain.
- Protective function : it is the main function of the skin, protecting our body from all the external aggressions to which we are exposed on a daily basis. It protects us from shock and friction, aggressive products, pollution, but also extreme temperatures, 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, stimulating certain T lymphocytes and white blood cells for a good immune defense
- The emotional function: it is quite unconscious at home, but the skin is a means of communication in its own right. She informs our entourage about our condition and participates in visual communication. For example, it blushes to show discomfort, can become very white in case of illness, or dull in case of fatigue, and items such as dark circles or imperfections can say a lot about our state of health.