The wonderful vital functions of the skin
Roger castell
The skin is one of the most important organs of the human body for the maintenance of health, but most adults are unaware of this essential role and misunderstand the reality of the various functions it performs and which we will present after recalling its composition and constitution.
1 – Composition of the skin
The skin is the largest and heaviest organ in the human body, since it covers the surface of 2 m2 with an estimated weight of 3,5 kg. From a chemical point of view, the skin includes on average 70% water, 27,5% protein, 2% fat and 0,5% mineral salts and trace elements (1) On a physical level, the pH (acid-base potential) of 4,7 to 5 shows a medium acid, highly hydrated and highly protective against pathogenic bacteria that usually thrive in a basic medium. However, in order not to modify this pH, the water and the products used (soap, creams, ointments, etc.) should be rather acidic, which is rarely the case. (2) Finally, the skin normally has an antioxidant potential (rH2) effective and high resistance to the many attacks we face. But the defense capacities are very variable because they depend on the level of vitality of each one of us.
These various pieces of information all testify to the importance that the skin must play in the preservation of life, recalling in particular the high concentration of water (70%), proteins (27,5%), the complete absence of sugars and the fundamental role of the hygiene products to choose well, to obtain maintenance without inconvenience and which is really effective.
2 – Structure of the skin
The skin is made up of three layers of closely related overlapping tissues, each of which has specific functions: the epidermis, the dermis and the hypodermis (see diagram). But there are also other energy-type envelopes (etheric, auric, psychic, etc.), mentioned by Alain de Luzan in his article and which we will present in another dossier.
The epidermis.
This semi-permeable outer part of the skin, less than a millimeter thick, has several layers of cells, including a horny superficial layer which provides protection. Beneath this is the unrecognized yet very active corrugated basal layer. According to the biologist Marchesseau (3) this layer receives and transforms the waste products from the tissues and blood of the neighboring capillaries, it manufactures vitamin D from cholesterol and it protects the skin from harmful solar rays, by browning, by activating the secretion of melanin (brown pigment) , to avoid the risk of oxidation and burning. It constitutes a real protective barrier against external factors (pollution, sun, cold) and the risks of internal water loss. Finally, it ensures permanent cell renewal to replace worn cells, which gradually migrate to the stratum corneum composed of dead cells (dandruff), which are eliminated when the subject washes, dresses and gets active. The complete cycle of creation of new cells and transformations to obtain the stratum corneum is 15 to 22 days. (4)
The dermis.
Located under the epidermis, the dermis is the inner layer of the skin, 4 times thicker than the epidermis. The dermis protects and repairs damaged tissue (cuts, grazes), thanks to the collagen it is made of, which allows it to create scar tissue. The dermis nourishes the epidermis and contains nerve endings, blood vessels, sometimes adipose tissue and especially the glands which promote the elimination of toxins. The sweat glands produce sweat, the apocrine sweat glands are responsible for body odor, the sebaceous glands contain the roots of hair follicles (hair and hair) and secrete sebum, a hydrolipidic biofilm which protects and softens the epidermis.
The hypodermis
Located under the dermis, the hypodermis is an adipose connective tissue crossed by the nerves and the vessels arriving in the dermis. It plays several roles, including that to cushion the pressures to which the skin is subjected, especially in the buttocks and heels, to protect body from temperature variations (insulation), store fats (energy reserve), to accumulate waste (acids, spent minerals) and modeler the silhouette (slender or coated). But fat, cellulite, calcifications and lipomas (benign fatty tumors), swell the cells and deform the body as health deteriorates. Efforts should be made to avoid their concentration by choosing the most suitable lifestyle habits.
3 – Main functions of the skin
The skin is much more than a simple protective envelope. It is an organ in its own right, whose functions must be known to really understand the causes of the diseases that affect it. The skin indeed plays several fundamental roles including that of protection vis-à-vis the outside, thermal regulation, purification, information and in addition, the skin has an undeniable psychosocial and "aesthetic" function, by its color, its texture and its "decorations".
Protection
True interface with the outside world, the skin cconstitutes a flexible and effective barrier, which protects the organs from most external aggressions: infections, injuries and harmful sun rays. This is particularly the case UV from which it protects itself, thanks to the presence of melanocytes, producing melanin, this antioxidant brown pigment, which ensures the tan of the skin. By isolating the inner body environment, the skin also limits water loss, while being semi-permeable to external liquids (ointments, essential oils, etc.). Finally, the skin plays an important role in the immune protection of the human body, thanks to the presence between the epidermis and the dermis of the Langerhans cell. Capable of phagocytosis, it ingests cellular debris and even cancer cells present in the epidermis (5) .
Regulation of body temperature
Depending on its thickness, texture, color and hairiness, the skin absorbs and emits heat more or less well, in particular that produced by solar radiation (visible, ultraviolet or infrared). The organism is able to adapt by changing the color of the skin (tanning, redness) and by secreting sweat. This liquid helps to maintain the body temperature at 37°, depending on the temperature outside or inside the body (muscular effort or fever, for example). The cooling of the skin is obtained thanks to the evaporation on the surface and the freshness of the ambient air. Sweat, composed essentially of water (99%) also contains vitamin C, minerals and acids (uric, lactic, etc.). It is this presence of lactic acid that would attract mosquitoes. Sweating is regulated by the sympathetic nervous system. We speak of “cold sweat” when it is caused by violent stress (fear and terror).
Blood cleansing
In the dermis are 2 filters specialized in the purification of blood, the sweat and sebaceous glands, and a vast network of blood capillaries which contain approximately 10% of the blood of an adult. During physical exercise, or in a supercaloric bath (with very hot water or very hot air from the sauna), the capillaries dilate, to allow the blood to eliminate water and toxins contained in sweat. and sebum.
The sweat glands remove soluble waste products from the blood (acids and spent minerals), as do the kidneys. The sweat produced is comparable in its composition to urine, so that the sudoriparous represent the extraordinary number of 3 million small kidneys.
The sebaceous glands eliminate insoluble waste of a colloidal nature (fatty acids, microbial waste, etc.) which saturate the lymph. These 300 glands of course secrete sebum which serves as a lubricant for the epidermis, but they are also comparable to the lungs which eliminate mucus (sputum) when the concentration of “viscous” waste becomes too high.
The article on diseases of elimination will develop these 2 vital functions for health.
Sensory information
Thanks to the many nerve endings contained in the dermis, the skin is gifted with extreme sensitivity, especially at the fingertips, which allows from birth, by exploring the environment, to develop the finesse of the sense of touch (texture, hardness, roughness, etc.). But the skin also has three other types of receptors, which inform the brain about pressure, temperature and pain, to allow it to react appropriately to various life situations.
The skin is also the support for acupuncture, massage techniques and reflexology (feet, hands). These important topics will be developed in other articles.
Psychosocial function
With the gaze, the skin is the first contact we have with the relational environment. Shaking hands, holding in one's arms, offering a kiss, are affective and social practices, which put the epidermis in contact to testify to the level of one's affection (love, tenderness, friendship) or simply one's social consideration.
The texture of the skin (color, softness, health) plays an important role in the construction of personality and self-esteem, but also in the radiance that everyone spontaneously exerts on others. From time immemorial, the skin has been the support of marks (desired or imposed) of belonging to a social group (ethnic, religious or cultural). According to civilizations, times and age, we have tended to hide or expose the skin to others. For this purpose, paintings, tattoos, piercings have been used and contemporary society uses the means offered by cosmetics to "beautify" the skin and enhance it, taking into account its nature (color, pallor, tan, scars , wrinkles…).
Synthesis of vitamin D
Exposed to sunlight, especially ultraviolet rays in the morning, the skin promotes, from cholesterol, the synthesis of vitamin D necessary for the growth of children, for bone restoration after a fracture and throughout life, for mineral balance skeletal bones.
4 – Skin conditions
Dermatology is the medical specialty that deals with skin conditions. Problems can be localized to one part of the body, or spread over a large area. The causes are often linked to an imbalance of the cutaneous biofilm, but the integrity of the skin can be altered by external agents: micro-organisms, insect bites, burns, trauma and chemical pollution, but also be the simple consequence of a need to eliminate toxins contained in excess in the body.
Skin flora.
Human skin can host micro-organisms (bacteria, fungi, mites, etc.) which constitute a more or less permanent skin flora. This “microbiota” has a variable composition depending on the individual, depending on age, sex, activities and environment. It also varies according to the parts of the body: hands, scalp, face, armpits, back, pubis... It is estimated that the skin of an adult can sometimes harbor up to a thousand billion bacteria of different species, which feed waste products released by the skin and various secretions. This high presence poses a hygiene problem, to use effective hygiene care, without disturbing this natural micro-biota.
Common skin disorders
The micro-organisms of the cutaneous flora can become pathogenic due to an imbalance of the cutaneous environment, caused by an excess of dirtiness or cleanliness, but also by a chemical product or an injury.
Dead cells (dandruff) that accumulate on the epidermis, mixed with sebum, sweat, dust, earth and various substances (cream, make-up, etc.) can form a layer promoting the development of micro- organisms (bacteria, mites), likely to produce a very unpleasant characteristic odor.
Excessive "stripping" with an exfoliator or using overly aggressive cleansing products (biocide, antibiotic or cosmetic) neutralizes sebum and kills the skin's protective organisms. This can result in a sudden proliferation of fungi, leading to mycosis.
Chemicals in contact with the skin can cause itching or allergic reactions. This is the problem experienced by Norbert (68), who suffered from reactive urticaria for several days. “Last year, I bought a shirt on sale, which I immediately wore because I thought it was pretty. It was very hot all day and I sweated a lot. In the evening my skin was covered with red patches and I had unbearable itching, which led me to consult a doctor. I was forced to take an antihistamine, I who never take medication. It was the next day that I understood the cause of my problem. My skin reacted violently to defend myself against the fungicide sprayed on the shirt to protect it from mold. From now on, whatever the origin of the manufacture, I no longer forget to wash and iron the garment before wearing it. You can learn to live at any age.
– Hormonal disturbances during adolescence, can increase the secretion of sebum (natural lubricant of healthy skin) leading to oilier and thicker skin. This skin reduces the appearance of wrinkles because the sebum helps keep the epidermis moist, but oily skin is more likely to produce acne pimples on the face or clogged pores called “blackheads”. Moreover, excessive degreasing can aggravate the secretion of sebum and this is why gentle cosmetics without alcohol and with an adapted pH are recommended for people with oily skin.
Disposal issues
When the production of toxins is very high, the body will put in place the conditions to preserve the balance of the various constituents of the internal environment by favoring the elimination of excess toxins which could not be expelled in a normal way. and daily. If the nervous energy is sufficient, the skin can serve as an emunctory. Most skin "diseases" (eczema, psoriasis), are to a large extent the consequence of the body's need to purify the internal environment. An article will develop this subject.
Other conditions
These can be of local causes or the reflection of a more general affection. This is the case, for example, of scleroderma (skin induration), parasitic fungus (scabies) or microbial (impetigo) infections, local deficiency or absence of pigmentation (vitiligo, albinism), not to mention tumors of the skin, whether benign (lipoma, angioma) or more serious (melanoma and cancer).
5 – Criteria for healthy skin
Healthy, well-hydrated skin has a supple, clean and taut epidermis, which immediately regains its place after being pinched between the thumb and forefinger. Its acidic pH is preserved by drinking light and rather acidic water every day (water with reverse osmosis or from light sources, such as Montcalm or Mont Roucous) and by washing with filtered, because mains water in France is very basic with a pH close to 8. The use of soaps and cosmetic products could also have a negative influence on this pH by making it more basic and modifying the nature of the skin micro-flora.
Healthy skin, which reflects health, must be maintained by various natural activities, in particular sweating (hot water from baths or hot air from the sauna), friction with a horsehair glove, aromatic anointings with essential oils, air baths , sun and sea, moderate muscular activity, massages, etc. On the other hand, dry, cracked, thick, cold skin, covered with growths (warts, senile filth, etc.) or diseases (eczema, redness, itching, etc.), testifies to failing health, which must be corrected as soon as possible. early.
1 – Dr Jean-Pierre Césarini, The skin, What do I know, PUF edition, Paris.
2 – See the article on hygiene products.
3 – Pierre Valentin Marchesseau, The skin, booklet n°19, author's edition, Spirvie-Natura.fr.
4 – Dr JP Césarini, The skin, p. 28 and 5 – Dr JP Césarini, p 34.