Ans.Human skin consists of two layers.
1. Epidermis is the outer protective layer without blood vessels.
2. Dermis is the inner layer containing blood vessels, sensory nerve endings, sweat and oil glands, hairs and fat cells.
Role in Homeostasis
i)Skin performs important role in the regulation of body temperature.The thin layer of fat cells in the dermis insulates the body. Contraction of small muscles attached to hairs forms 'Goosebumps'. It creates an insulating blanket of warm air.
ii)Skin helps in providing cooling effect when sweat is produced by sweat glands and excess body heat escapes through evaporation.
iii)Metabolic wastes such as excess water, salts, urea and uric acid are also removed in sweat.