Describe the function of the various parts of the mammalian skin.

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Epidermis which has three layers; which are:-
  • Cornified layer that protects against dessication; and mechanical damages;
  • Granular layer with living cells that give rise to cornified layer;
  • Malphigian layer which actively divides to give rise to granular layer cells. Has melanin which screens against U.V light; has cells that produce melanin. 
Dermis layer which consists of many structures as follows:-
  • Blood capillaries that supply food and oxygen; and remove excretory products;
  • Arteries that vasolidate; and vasoconstrict; to regulate the temperatures.
  • Has sweat glands that produce sweat which consists of water and salts; Sodium chloride, urea and lactic acid’ acting as an excretory organ;
  • Sweat produced evaporates to cool the body.
  • Has hair follicles which have hair; which insulates against heat.
  • Through heat regulation by lying and rising the hair, skin acts as a temperature regulator;
  • It has nerve endings which are sensitive to various stimuli; the skin therefore acting as a sensory organ.
  • Sebaceous glands which produce secretions containing oily substances are water repellent; antiseptic; and cracking of skin.
  • Subcutaneous fat which insulates the body against heat loss; synthesizes Vitamin D.

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