Skin
Cosmetic Surgery - Plastic Surgery - Aesthetic Medicine - Reconstructive Surgery
The skin is a very particular organ, it is at once the
boundary of the body, protecting it against external aggression, an
organ of sensory contact and exchange, an organ of social communication
and a mirror of internal diseases, environmental changes and of course
emotions. Looking at yourself in the mirror is not to see an organ but
is to watch yourself.
The skin is the largest organ of the body, the surface of the skin of
an adult varies between 1.5 and 2 square meters. The total weight of
the skin is between 2 and 3 kilograms and its thickness is from 0.5 mm
(eyelids) to 4 or 5 mm (upper back).
Three mains layers form the skin:
The epidermis, on the surface. This has three functions:
To act as an impermeable barrier formed by the stratum corneum (keratinocytes in a state of permanent renewal).
To act as a barrier against the sun, using melanocytes;
To act as an immunological barrier made up of the network of Langerhans cells, just beneath the stratum corneum.
The turnover time for the epidermis is about 6 weeks; the speed and
quality of renewal are modified by physical attacks, inflammation,
wound healing and aging.
- The dermis, below, is of variable thickness depending on the area of the body. This is responsible for the resistance and flexibility of the skin. The dermis is a fibrous tissue consisting mainly of collagen and elastic fibres synthesized by fibroblasts. The dermis is criss-crossed by many blood capillaries responsible for skin nutrition and the control of body temperature.
- The hypodermis, below the dermis, is rich in fat. It is a kind of airbag that will separate the skin from the fibrous membranes surrounding the deeper organs, muscles and bones. The hypodermis is criss-crossed by nerve fibres and is well irrigated by blood circulation. The hypodermis is made up of fat cells, the adipocytes. The fatty tissue is divided into fat lobules. Nerves and vessels pass between the connective septa separating the fat lobules.
The brain is constantly informed by the skin about
temperature, pressure and touch by specialized sensors located at the
upper dermis. Nerve endings extend through the epidermis to the skin
surface.
In the skin, close cooperation between the dermis and epidermis gives rise to complex organs called the annexes:
- Surface hairs which act as body decoration, protect against external attacks and are responsible for skin sensitivity through responsive sensors located in the dermis around their roots.
- The hair, which follows a particular cycle with a growth phase (a few months to ten years), a regression phase (3 weeks) and a fall phase. The hair follicle is at rest (for 2-5 months) and then produces a new hair.
- Nails, which protect the fingertips and allow delicate handling.
- The sweat glands which play a very important role in the thermoregulation of the human body with the production of sweat.
- The sebaceous glands that produce an oily substance called sebum as a result of the action of male hormones at puberty. Sebum is a natural moisturizing factor for the skin.
The number of diseases affecting the skin are very
numerous, they can be grouped according to their cause: external agents
(cold, heat, sunlight, X rays, medicines, etc.); psychological factors;
circulatory diseases, diseases due to pathogens (bacteria, viruses,
parasites); genetic diseases; endocrine and metabolic disorders;
immunological disorders; disorders of the nervous system and skin
tumours (benign or malignant).
The skin provides a prime testament to the aging of the body. Three
factors are involved in skin aging: the genetic factor (based on
different individuals); external factors (especially the sun) and
environmental factors (lifestyle, the subject’s state of the health
etc.).
The aging skin atrophies and becomes thinner. It will wrinkle, dry out
and become rougher to the touch. Spots appear on the skin and wrinkles
occur (grooves between the nose and the mouth, and on the forehead and
cheeks).
Aesthetic medicine and aesthetic plastic surgery can help reduce this type of aging but often temporarily through:
- The use of fillers (hyaluronic acid);
- Injections of Botulinum toxin or Botox® which decreases muscle tone so as to reduce wrinkles;
- The reinjection of autologous fat or lipo-filling/lipostructure. This involves is a real graft of fat cells taken from the patient himself (autograft).
- Dermabrasion which is a technique for eradicating blemishes and smoothing the facial skin using a burr or very fine sandpaper.
- The temporal lift: this lift corrects the signs of aging in the forehead and cervicofacial regions, the lateral brow, and crow's feet, putting a mild tension on the outer part of the eyelids. It is often associated with eyelid surgery or blepharoplasty.
The best approach to delaying the aging of the skin is to reduce sun exposure in childhood. The skin should always be protected by creams and suntan lotions adapted to suit the various skin types. There are many products, cosmetics and medicines (based on collagen, fatty acids, vitamin E, etc.) for combatting aging. However, not all these products have always proven scientifically effective.