The skin, which is also called the cutaneous membrane, forms a protective, waterproof outer covering for the whole body. The skin plays an important role in providing sensory information of the external environment so the internal environment can adjust and regulate heat , absorption, excretion and secretion.

The main layers of the skin are the epidermis which is a thin portion, followed by the deeper, thicker dermis. This is followed by further layers that lie under the skin; a fatty layer called the subcutaneous fat layer. The dermis is made up of dense connective tissue that is tough and flexible. It contains collagen and a number of structures such as, nerve fibres, blood capillaries, arrector pili muscles, sweat glands and sebaceous glands. Beneath the dermis, lies the subcutaneous fat layer which is composed of loose connective tissue. It helps to anchor the dermis to the underlying tissues and organs.