Skin is composed of the epidermis and the dermis. Below these layers lies the hypodermis(subcutaneous adipose layer), which is not usually classified as a layer of skin. The outermost epidermis is consists of stratified squamous epithelium with an underlying basement membrane. It contains no blood vessels, and is nourished by diffusion from the dermis. The main type of cells which make up the epidermis are keratinocytes, with melanocytes and Langerhans cells also present. The epidermis can be further subdivided into the following strata (beginning with the outermost layer): corneum, lucidum, granulosum, spinosum, basale. Cells are formed through mitosis at the innermost layers. They move up the strata changing shape and composition as they differentiate, inducing expression of new types of keratin genes. They eventually reach the corneum and become sloughed off (desquamation). This process is called keratinization and takes place within about 30 days. This layer of skin is responsible for keeping water in the body and keeping other harmful chemicals and pathogens out. The dermis lies below the epidermis and contains a number of structures including blood vessels, nerves, hair follicles, smooth muscle, glands and lymphatic tissue. It consists of loose connective tissue otherwise called areolar connective tissue - collagen, elastin and reticular fibres are present. Erector muscles, attached between the hair papilla and epidermis, can contract, resulting in the hair fibre pulled upright and consequentially goose bumps. The constantly peeling off dead cells of the epidermis mix with the secretions of the sweat and sebaceous glands and the dust found on the skin to form a filthy layer on its surface. If not washed away the dirt and dead skin slurry begins to decompose emitting a foul smell. Use a natural sunscreen when possible, regardless of whether or not you plan on spending much time in the sun. The sun's rays are very damaging and if you get in the habit of applying sunscreen everyday, you will never be left without protection. The suns most beneficial rays occur at sunrise and sunset. Over the years, beauty experts and skin doctors have come up with a vast array products to treat and minimize wrinkles. Anti-wrinkle creams and ointments help reduce the appearance of wrinkles and prevent new ones from forming. These wrinkle ointments and anti-aging creams help a lot in restoring the skin's firmness and elasticity. In addition, these products contain anti-oxidants and retinol that not only aids in reducing wrinkles and fine lines on the skin, but also stimulates collagen production.
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