Skin structure diagram

The outer layer of the skin is called the epidermis and it is much thinner than the deeper dermis. At the base of the epidermis is the germinative layer, where new epidermal cells and melanin are produced. Melanin gives skin its colour and absorbs UV light to protect the deeper cells in the skin.

The dermis contains fibres of collagen, and fibres of elastin that can stretch as the skin moves, but return to their original shape after a movement. As we age, elastin fibres lose their elasticity, and UV exposure can speed up decay of these fibres.

The dermis also contains hair follicles from which hair grows. An erector muscle contracts to pull the hair up in cold conditions. Erect hairs help trap warm air against the body. Sebaceous glands in the dermis produce sebum, which helps provide a waterproof covering for the skin and keeps the skin supple. Arteroioles carry blood to the surface of the skin and more flows in warm conditions to help the skin cool. Venules carry blood away from the skin back to the heart.

Nerve endings in the dermis help detect pressure, pain, touch and temperature. Adipose tissue deep in the dermis helps provide insulation to underlying structures.