Skin is made up of the upper epidermis and lower dermis. The upper epidermis has many layers of cells. The topmost layers, composed of dead cells,lipids,keratin,urea,salts and 30 per cent water,together form the stratum corneum. They also make up skin’s natural moisturizing factors (NMF). The stratum corneum forms a barrier that protects the skin and prevents toxins from entering.
The epidermis consists of five layers. The lowermost layer of the epidermis,known as the stratum basale, is of significance to us. It comprises cells called keratinocytes and melanocytes. Keratinocytes form the factory that produces new cells. From this layer, old cells gradually travel upwards to reach the surface of the skin and are then shed in twenty-eight days. Melanocytes produce the pigment melanin that gives skin its colour.
The Other Layers
The lower part of skin is known as the dermis. The dermis contains an important molecule called hyaluronic acid-a polysaccharide glycosaminoglycan -that builds moisture in the skin. It has the unique capacity to bind and retain water molecules. It helps maintain the resilience and smooth texture of skin.
The dermis is also comprised of collagen fibres that give skin structural support and elastin fibres that give skin its suppleness and elasticity.
sweat glands that secrete sweat, sebaceous glands (the oil glands of the skin) that secrete an oil called sebum, hair follicles (hair roots),blood vessels,lymphatics and nerves all lie in the dermis.
Below the dermis lies the subcutaneous or fat layer, followed by fascia,muscle and bone.