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The Skin

The skin is the body's largest organ, consisting of three layers; the epidermis (the outer layer), the dermis (the thick part which one feels when the skin is picked up), and the subcutaneous tissue (the fatty cushion on which the skin rests).

The epidermis is the most superficial layer, varying in thickness, being thickest on the soles of the feet and palms of the hands and very much thinner on the face. The eyelids are thinner still. The outer layer of the epidermis consists of dead or keratinised cells that have no protective oils and it is these cells that become dry and flaky if not correctly treated. The outer layer of dead skin cells should be continually shed.

Further down in the epidermis is the basal layer which is responsible for making new epidermal cells. Among these new cells are a number of melanocytes (pigment cells) which produce melanin (pigment). This pigment is responsible for the natural colour of our skins and darkens in response to sun exposure causing tanning. All people have the same amount of melanocytes per square centimetre of skin. It is the amount and type of melanin produced that determines the natural colour of the skin.

The dermis is much thicker than the epidermis and consists of numerous structures. These include:

Capillary blood vessels which bring oxygen and nutrients to the skin and carry away deoxygenated blood in tiny veins.
Lymphatic vessels which drain waste products such as proteins, water, and salt.
Sensory nerve endings carry sensations of touch pain and cold to the brain.
Sweat glands which help regulate body temperature and get rid of waste materials.
Sebaceous glands are found almost all over the body, usually opening into a hair follicle. They secrete sebum (oil) which keeps the skin moist and the hair soft.
Hair can be found almost all over the body except on the lips, palms, and soles. Each hair has its own muscle which can contract, pulling the hair erect and trapping air - known as a goose-bump.
Collagen and elastin fibres give the skin strength and suppleness and will deteriorate with age.

Subcutaneous tissue contains fat cells that help to reduce heat loss and gives us our shape.

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