The skin consists of two layers. The outer layer is called epidermis and the inner layer is called dermis.
The epidermis consists of layers of cells. The outer layer is called corneum layer. This is made up of dead cells and contains a protein called the keratin. The corneous layer is thick on palms and soles. Due to wear and tear it is shed off in the form of scales.
The inner layer of epidermis is called as Malpighian layer or germinal layer. This layer contains living cells. The inner part of the skin is the dermis. This contains connective tissue, blood vessels and nerve fibres. Fat is deposited in the deeper part of dermis.
There are two types of glands in the skin. They are the sweet glands and the sebaceous glands. The sweat gland is a coiled tube or duct. It ends in dermis. The duct of the sweat gland opens to the outside through a sweat pore.
Sebaceous glands are also known as oil glands. They produce an oily substance called as sebum. The sebaceous gland is like a sack. It has a duct through which it opens in to the hair follicle. Sebum prevents the skin from becoming dry.
Hair develops from the hair follicle. The hair shaft arises from the hair follicle. The hair shaft is the visible part of the hair. It contains dead cells and pigment.
Through the sweat pores sweat comes out of the body. It gets evaporated and keeps the body cool. In winter due to cool environment, the blood vessels narrow and sweat production is reduced. Thus, the skin keeps the body warm. The sweat glands do the excretory function also. They absorb the excess water, sodium chloride, urea and urates form blood. These substances are sent out in the form of sweat.