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Skin's Function

The skin is the body's largest organ, with a total surface of about 1.8 square meters and weighing about 11 kilograms. It is a complex system made of multiple layers of tissues that protect our muscles and other organs. It is made up of about 70% water, 25% protein, and 2% lipids. Skin comes in a broad range of pigmentation, varying among different populations, and skin type can range from dry to oily.

The uppermost layer of the skin is known as the epidermis while the deeper layer is called the dermis. The dermis contains collagen and elastin, which help keep the skin flexible and firm. The dermis is also made up of sebaceous glands, sweat glands, lymph vessels, hair follicles, and nerves. Below the dermis there is also a layer of fat cells. Since the skin is the barrier between us and the environment, it plays a critical role in protecting the body from pathogens, principally germs. Its other roles include:

     1. Insulation: The skin provides an insulation layer for the body's organs to protect them from hot or cold temperatures.
 
     2. Temperature regulation: Because the skin has a far greater blood supply than it strictly requires, it is able to control energy loss through radiation, perspiration, convection, and conduction. Even within quite extreme temperature ranges, our skin will maintain our body at 37C by:
  • vasoconstriction to decrease the flow of heat to the skin
  • vasodilation to increase blood flow to release heat
  • stopping or starting of sweating to maintain body temperature
  • shivering to increase heat production in the muscles
  • secretion of norepinephrine, epinephrine, and thyroxine to increase heat production
     3. Sensation: The skin's nerve endings react to:
  • touch
  • heat and cold
  • pressure
  • vibration
  • tissue injury
     4. Control of evaporation: The skin serves as a dry and impermeable barrier to fluid loss; when this function is lost, the massive fluid loss associated with burns becomes possible.
 
     5. Aesthetics and communication:  Our skin, especially in the facial area, is a primary communication medium through blushing, blanching, smiling, frowning and other ways that we may not even be aware of but which affect the way others react to us. Others 'read' our skin to determine our mood, physical state, and attractiveness.
 
     6. Storage and synthesis: The skin stores both lipids and water and provides a way for us to synthesize vitamin D, which is needed for the absorption of calcium and phosphate by the action of ultraviolet rays in certain areas.
 
     7. Excretion: Our sweat contains urea but at a mere 1/130th of the concentration found in urine, so excretion by sweating is at most a secondary function to temperature regulation. Excess salt and other waste products, including water, which is lost continuously, are also excreted through the skin.
 
     8. Absorption: The skin is able to absorb oxygen, nitrogen, and carbon dioxide in small amounts. Absorption also plays a useful role in medical treatments, where ointments and other compounds can be introduced to the body through the skin.
 
     9. Water resistance: Because the skin provides an essential water-resistant barrier, nutrients such as vitamin B folates and others are not washed out of the body.

 

Contact Information:

Canadian Skin Patient Alliance
2446 Bank Street, Suite 383
Ottawa, Ontario
K1V 1A8
 

Christine Jackson, Executive Director
phone: 613-422-4265
fax: 613-422- 4267
 

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