Skin is the outer covering of the body; it is one of the largest organs of the human body. It is the sense organ of touch, but plays certain crucial roles such as: regulation of body temperature and waste excretion. Skin along with hair and nails form the integumentary system. They provide external protection to the body. Skin is composed of three layers: the epidermis, dermis and hypodermis (subcutaneous layer). Skin colour depends on a pigment named melanin present in the epidermal layer.
The epidermis is the outermost layer of the skin. It is called the protective layer of the skin, as it protects the body from the harmful ultraviolet rays. This layer is composed of thin and flat cells and dead cells. The epidermis contains two layers: the stratum corneum and basal layer. The stratum corneum is relatively waterproof and safeguards skin from microbial invasion. Basal layer is located above the dermis and has the colour pigments melanin in it.