Skin functions and structure
Every day you look at the skin on your body, but do you really know much about it.
Its the largest organ in your body and has five functions. It:
Regulates body temperature by controlling evaporation and conserving heat
Protects the rest of your body from the external environment and is the bodies first line of defence
Registers sensations hot and cold, touch, pressure, vibration and tissue injury
Excretes and absorbs, and
Synthesises vitamin D.
Structure
An average human has a surface skin area of between 1.5 and 2 square metres and without skin you would simply evaporate.
Skin holds 650 sweat glands, 20 blood vessels and more than a thousand nerve endings and has two layers.
The thicker epidermis, which is the outermost layer of skin and is the waterproof wrapping, is thinnest on the eyelids at 0.5mm and thickest on the soles of feet and palms of hands at 1.5mm.
As the epidermis does not contain any blood vessels, small capillaries that reach the upper layers of the dermis nourish the cells in the deepest layers.
The second layer is the dermis, which varies in thickness from 0.3mm on the eyelids to 3.0mm on a persons back. The dermis contains collagen, elastic fibres, nerves and hair follicles.
In the upper regions of the dermis there are free nerve endings, which allow you to feel sensations of warmth, coolness, pain, tickling and itching.
Sweat and oil glands begin in the lower region of the dermis aptly called the reticular (as in reticulation) region. This is where skin gets its elasticity and if it is forced to expand quickly such as in pregnancy or obesity, small tears appear in the dermis and are seen on the surface of the skin as stretch marks.
Skin cells have a short life cycle of roughly four weeks from when they are produced in the lower layers of the epidermis to when they reach the upper level (the surface) where they are cast off.
If skin is damaged unexpectedly by abrasions, cuts and burns the formation of cells speeds up to replace the skin and heal the wound. If the damage is severe this process makes a scar.
Your skin produces a natural substance called sebum, which is secreted from the sebaceous glands. It helps to prevent excessive evaporation of water from the skin. It keeps skin soft and pliable, but as skin ages the sebaceous glands are less active so you need to replenish your skin with natural preparations to retain the moisture.
Sweat and sebum exit the skin through tiny openings called pores.
When products containing chemicals are used on the skin, the delicate balance of the way skin renews itself can easily be disrupted.
Using skin care products that are made from natural ingredients work in a complementary way to support the skins structure and help it to function correctly.