Scientific Area:
Hair and Scalp

Un follicule pileux est une formation d'origine épidermique, ancrée dans le derme et constituée d'un poil et de sa gaine. La formation des follicules pileux est précoce ; ils commencent à apparaître dès le deuxième mois de gestation. Ces follicules continuent de se former tout au long de la grossesse. À la naissance, le bébé possède la totalité du capital folliculaire pour lequel il est génétiquement programmé, et aucun autre ne se formera par la suite.

A hair follicle is a formation of epidermal origin, anchored in the dermis and consisting of a hair and its sheath. The formation of hair follicles occurs early. They begin to appear as early as the second month of gestation. These follicles will continue to form for the entire duration of the pregnancy. At birth, the baby will indeed have the entire supply of follicles with which it was genetically equipped and from this moment on, no others will form.

Some parameters and characteristics should be taken into consideration when assessing hair types and morphologies: shape, density and appearance. The appearance of hair, in the form of lanugo, occurs during the fourth month of pregnancy.

Les glandes sébacées sont des glandes qui sécrètent du sébum, une substance huileuse et acide dont le pH est de 3,5. Elles sont reliées latéralement au follicule pileux. On trouve des glandes sébacées avec une densité d'environ 100 par cm² sur l'ensemble de la peau. Chez l'être humain, elles sont réparties sur toute la surface cutanée, à l'exception de la paume des mains et de la plante des pieds.

The life cycle of hair and its subsequent growth occur at a speed of 1-1.5 cm per month. Hair is a living element that follows a follicle cycle with an average duration of 2-6 years. In humans, unlike other mammals that are subject to a periodic change, this cyclic evolution is not synchronous (therefore each hair is independent from the others).

Les pellicules sont une affection du cuir chevelu qui apparaît généralement entre 10 et 25 ans. Elles peuvent s'atténuer entre 45 et 55 ans ou persister jusqu'à un âge avancé. Elles résultent d'un renouvellement accéléré des cellules épidermiques : en raison d'une migration trop rapide, ces cellules ne parviennent pas à maturité complète avant de se détacher. Des squames blanchâtres ou jaunâtres (amas de cellules de la couche cornée) se forment et se détachent, s'accumulant par plaques ou se répartissant souvent de manière uniforme sur le cuir chevelu.

The sebaceous glands are glands that secrete sebum, an oily, acidic substance with a pH of 3.5. They are connected laterally to the hair follicle. Sebaceous glands are found with a density of approximately 100/cm2 throughout all areas of the skin. In the human body, they are located across the entire surface of the skin, except for the palms of the hands and the soles of the feet. Sebaceous glands are also found in the external auditory meatus (ear canal) and on the eyelids, where they are long and flat. Here they are called tarsal or Meibomian glands.

The hair on our bodies has a particular structure and is divided into thin and thick hair. Thin hair, also called lanugo or vellus, is located on all skin surfaces except for the palms of the hands and the soles of the feet. Thick hair, also called terminal hair, is dark and located only in some areas such as the scalp, the armpits, the pubic area, the beard area in the case of men, etc…

The scalp is an ultra-specialized area of the skin, where hair is anchored. Like other hair, also the hair on the scalp originates from a hair follicle, called a bulb.

The scalp is an ultra-specialized area of the skin, where hair is anchored. Like other hair, also the hair on the scalp originates from a hair follicle, called a bulb.

Le cuir chevelu est une zone cutanée ultra-spécialisée où sont ancrés les cheveux. Comme les autres poils, les cheveux du cuir chevelu prennent naissance dans un follicule pileux, appelé bulbe.