Skin: understanding its structure and essential role

03/03/2020

The structure of the skin is particularly complex. Composed of three layers - the epidermis (superficial layer), the dermis (intermediate layer) and the hypodermis (deep layer) - the skin constantly interacts with our environment. In this sense, its role is to protect the whole body by fighting against external aggressions.

WHAT IS THE STRUCTURE OF THE SKIN?

THE EPIDERM

This epithelial tissue is the most superficial part of the skin structure. It is composed of three different types of cells: keratinocytes, melanocytes, and Langerhans cells.

During their migration, keratinocytes produce keratin, a natural protein that protects the skin from the outside world. Melanocytes synthesize melanin. They are responsible for the pigmentation of the skin, thus playing an essential protective role against UV rays.

The Langerhans cells are indispensable for the defence of the body since they also fight against external aggressions and allergic phenomena.

If the structure of the skin is divided into three layers, the epidermis itself is divided into four distinct layers:

- the basal layer: this is the deepest layer of the epidermis and produces keratinocytes. It is also here that the melanocytes and Merkel cells are found, cells belonging to the neuroendocrine system which participate in the skin's sensitivity to touch. The basal layer ensures the regeneration of the skin through cell division. Indeed, the cells it produces will migrate continuously to the upper layers while undergoing various mutations;

- the spinous layer: it is made up of several layers of keratinocytes (between four and five) linked together and thus ensuring the skin's impermeability function. It is by migrating towards the upper layers that the latter will become loaded with keratin and melanin, thus ensuring the role of skin barrier. The name of this layer is due to the irregular and spiky shapes of the keratinocytes;

- the granular layer: this is the layer where the accumulation of keratin in the skin cells is observed. There are then only one to five layers of keratinocytes loaded with keratin, which then evolve into corneocytes;

- the stratum corneum: it is composed of corneocytes, the final phase of keratinocyte mutation, and epidermal fluid. The cells are now flat and translucent. As they die, they will gradually detach themselves on contact with the outside world. This layer is the protective barrier of the lower layers of the epidermis.

THE DERM

The dermis is the central part of the skin structure. It is located just below the epidermis and protects the nerve fibres and the vascular network. Four times thicker than the epidermis, it repairs and protects the tissues. It is essentially composed of collagen, a structural protein that gives tissues mechanical resistance to stretching. It also contains nerve endings and blood vessels. The dermis contains two different types of cells:

- fibroblasts: they are used to synthesize collagen;

- mast cells and histiocytes: they contribute to the immune system.

The dermis itself is composed of three layers:

- the deep dermis: it makes the link with the hypodermis by penetrating its fatty tissues. It contains numerous fibroblasts, collagen and elastin fibres;

- the reticular dermis: this is where the sebaceous and sweat glands are found. It is also here that the bulbs at the origin of hairs and hair are born;

- the papillary dermis: it is located just under the epidermis and is particularly rich in collagen and elastic fibres.

Irrigated by blood, the dermis ensures the nutrition of the epidermis by diffusion. Beyond this nutritive role, it ensures the function of thermoregulation and healing of the skin, while eliminating toxic products through the phenomenon of sweating. Finally, the fibroblasts it contains support the epidermis. Skin ageing (sagging, appearance of wrinkles) is notably due to the loss of the support and elasticity capacity of the dermal fibres.

THE HYPODERM

The hypodermis is the deepest and thickest layer of the skin structure. It is located just below the dermis and is particularly rich in fat, blood vessels and special collagen fibres called tissue walls. These hold the fat cells together. The hypodermis is traversed by nerves arriving directly into the dermis. Its role is extremely important as it ensures :

- protection : it absorbs the pressures to which the skin is subjected by absorbing shocks ;

- insulation : it protects the body from temperature variations ;

- energy: it stores fat.

Made up of lipid cells called adipocytes and connective tissue, the hypodermis directly impacts the morphology of every individual according to his age, sex and nutritional status. In fact, it is a kind of fat mattress, more or less thick depending on each individual's typology.

TAKING CARE OF YOUR SKIN: AN ESSENTIAL RITUAL

As you will have understood, the structure of the skin is particularly complex. Because it constitutes a real armour against external aggressions (heat, cold, UV rays, shocks...), it is necessary to take care of it in order to help it maintain itself and age well.

WASH HIS SKIN YES, BUT PROPERLY!

Bathing may seem obvious: eliminating sweat and dirt that accumulates on the skin, avoiding disturbing body odours, preventing the proliferation of bacteria and the risk of disease transmission... are all reasons that push us to wash ourselves daily. A healthy lifestyle (a varied diet, sport, no smoking, sensible alcohol consumption and good sleep) also contributes to beautiful, clean skin. However, sometimes our habits are not appropriate, as the very structure of the skin is much more fragile than it seems. The right gestures :

- choose a gentle cleansing product: avoid stripping your skin every morning and evening. For the body and face, we prefer a "soap-free" solution such as a surgras cleanser, dermatological bar. Their Ph is slightly acidic like the skin and they contain surfactants that are much less aggressive than traditional detergents. The little extra? Natural and organic products, much healthier for our body. To take care of the skin on your face, we recommend our organic facial cleanser enriched with pure organic aloe vera juice;

- prefer showers to baths: a long hot bath will only cause skin dryness. A quick shower, with warm water, finished off with a cool water jet, will be excellent for the skin tissues and will promote better blood circulation;

- Wipe your skin gently: no need to vigorously rub your skin to dry it! By dabbing gently with a terry towel, you preserve your epidermis.

FRESHEN UP WITH EXFOLIATION

To help the skin breathe, exfoliation is recommended once or twice a week. The structure of the skin, complex as it may be, has a similar life cycle from one person to another. The skin is renewed on average every 21 days: the cells migrate from the basal layer (the deepest layer of the epidermis, which produces keratinocytes) to the horny layer (the most superficial layer of the epidermis, the last bulwark against external aggressions). This migratory cycle known as "keratinization" ends with the death of these keratinized cells, leading to desquamation.

Scaling refers to those tiny pieces of dead skin, invisible to the naked eye, that break off and are replaced by new cells. However, these flakes, mixed with sebum, sometimes need a helping hand to fall off and give way to renewed, smooth and radiant skin. The use of an exfoliant is therefore ideal for making new skin... as long as it doesn't damage the epidermis!

To do this, opt for a fine-grain facial scrub (white sugar, grape seeds, rice powder...) or an enzymatic scrub with fruit acids. The skin of the face is fragile, so it needs a very special treatment. Exfoliation is performed on damp skin, once or twice a week for combination to oily skin, no more than once a week for dry, sensitive and reactive skin.

For the body, it is possible to turn to scrubs with thicker grains, such as those with fruit stone peels, sea salt crystals or brown sugar...

Far from damaging the very structure of the skin, exfoliation therefore allows you to say goodbye to dead cells piled up on the surface of the epidermis, to unclog pores and to soften the skin. We then move on tohydration, an essential step to help the skin fully play its role as a protective barrier!

HYDRATION: THE SECRET TO BEAUTIFUL, SUPPLE SKIN

Pollution, wind, perspiration, temperature variations, UV rays... The fragile structure of the skin is attacked daily without us even realizing it. One watchword: hydration. By fighting skin dryness, the skin retains all its suppleness and is therefore more resistant. Goodbye tightness, crocodile skin and premature ageing!

There are a multitude of moisturizing creams or nourishing treatments for the face and body. It is therefore necessary to choose a product adapted to your skin type: fair or matt skin, young or mature, dry or oily, you will need to give it the right care. At Akane, we offer products for every skin type, all organic and good for your skin!

Our natural moisturizers