Skin Facts by Andrea Shaw
Skin, the integumentary system, is the largest organ in the body, and it is simply amazing. It’s a strong barrier designed to protect us from outside elements. Skin layers, nerves, cellular functions, hair follicles, glands – all work together harmoniously to regulate and protect the body. Healthy skin is slightly moist, soft, smooth and somewhat acidic. Skin is the thickest on palms of hands and soles of the feet. It’s the thinnest on the eyelids. Our skin is a cell-making factory with miles of blood vessels, sweat glands, and nerves within a network of fibers. Skin on an average adult weighs 8-10 pounds and averages an area of about 22 square feet. It contains 1/2 to 2/3 of the blood in the body and 1/2 of the primary immune cells.
Each inch of skin contains approximately:
* Millions of cells (per inch)
* 12 feet of nerves (per inch)
* 650 sweet glands (per inch)
* 100 oil glands (per inch)
* 65 hairs (per inch)
* 1,300 nerve endings (per inch)
* 1,300 pressure receptors (per inch)
* 12 cold and hot receptors (per inch)
Skin is a protective barrier to outside elements and microorganisms. It has many defense mechanisms to protect the body from injury and invasion. Damage to our barrier layers is the cause of many skin problems, including sensitivities, aging, and dehydration. The skin’s most amazing feature is the ability to heal, thus protecting the body from infection and damage from injuries. Absorption of ingredients, water, and oxygen is necessary for our skin’s health. Skin absorbs oxygen and discharges carbon dioxide, and absorption occurs through the cells. Cells absorb topical products and creams through the hair follicles and sebaceous glands. The ability of ingredients to penetrate cells is determined by the size of the topical product’s molecule and the other characteristics of the product.
Skin is comprised of 2 parts, the dermis and the epidermis. The epidermis is the outermost layer of the skin. It is a thin, protective covering with many nerve endings. The epidermis is composed of 5 layers, called strata. The uppermost is stratum corneum – dead, scale-like cells which we continually shed, the stratum lucidum which is found on the lips, palms and soles, and the underlying stratum granulosum, stratum spinosum, and the innermost layer, stratum germinativam. Keratinocytes and epithelial cells protect the dermis lipids, surround the cells in the epidermis, which protect cells from water loss and dehydration.