The skin is the single largest organ that covers the entire surface of our body and consists of two layers mainly the epidermis and the dermis. Also beneath the dermis is the subcutaneous layer which is not part of the skin but separates the integument from muscles and bones, which will be included in the essay as tissue fibres are connected with those of the dermis. The main functions of the skin are protection of the tissues and organs that lie beneath against bumps and shocks, prevents entry of microorganisms and controls entry of foreign materials, protects the body from harmful radiation from the sun, controls water loss and regulates heat loss from the body and transmits social and sexual signals to others. However this essay will demonstrate how some of these different functions of the skin contribute to the maintenance of homeostasis which is the maintenance of a constant internal environment.
The epidermis of the skin consists of stratified squamous epithelium that is made of corneocytes, packed with keratin as a result of which the layers are tough and water resistant. Dominated by keratinocytes, thin skin has four layers which are stratum corneum (SC), stratum granulosum, stratum spinosum and stratum germinativum / basal layer while thick skin has an extra layer called the stratum lucidum which lies in-between the stratum corneum and stratum granulosum. The epidermis also consists of langerhan cells, melanocytes and merkel cells. Since the epidermis has no blood vessels or fibres, nutrients diffuse from the blood vessels located in the dermis and wastes are carried away which only happen between the cells close to the dermis which is the basal layer. These cells undergo mitosis and they move away from the dermal blood supply through the epidermis layers towards the SC as they mature in the process of keratinisation. These cells die due to lack of nutrients and cornify replacing the cytoplasm of the