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Anatomy of Skin

Skin is often considered the largest organ system of the human body. The average adult male has 18 square feet of skin weighing over 6 pounds. Skin is a remarkably durable structure with an incredible ability to regenerate and heal itself. Skin is comprised of two layers, the epidermis and dermis.

The epidermis is the outermost layer containing keratinocytes and melanocytes. Keratinocytes contain keratin, a protein, which provides a durable mechanical and moisture barrier to protect underlying tissues. Melanocytes are pigment (color) producing cells and are responsible for skin color. The epidermis is continually regenerating itself. New cells are constantly being made as the outer layers die and are worn away. Although the epidermis is the outermost layer of the skin, epidermal cells also line the oil and sweat glands as well as the hair follicles.

The dermis is the innermost layer of the skin and consists of collagen, a structural protein, which is produced by fibroblast cells. The dermis is extremely durable and flexible. Within the dermis are blood vessels, hair follicles, oil and sweat glands, and nerve endings.

The skin provides the following functions for the human body:

  1. Provides a physical barrier to the outside environment.
  2. Provides outward appearance.
  3. Conserves body fluid by preventing evaporative loss.
  4. Provides thermo-regulation/maintains body temperature.
  5. Excretes water and oils.
  6. Produces vitamin D in the presence of sunlight.
  7. Provides sensations of temperature and touch.
  8. Assists in the development of the immune system.