The Integumentary System

Fact: Your skin sheds about 50,000 cells per minute. That's about 72 million cells in a day!


Intuitively, the skin may not seem like a very vital organ for our survival, but it performs many important functions that we could not live without. The important functions of the skin are:
  • Physical Protection
  • Acts as a Biological Barrier
  • Maintaining Homeostasis
  • Sensations
  • Vitamin D Production

Sections of the Skin

The skin is not formed like a single sheet of paper, it has different levels with different function. The skin is broken up into three different layers, the epidermis, dermis, and hypodermis or subcutaneous.

Hypodermis or Subcutaneous Layer: This is the innermost layer of skin. Its main function is to store fatty tissue, or adipose, that insulates the body and stores energy.

Dermis: This layer is where collagen and elastic fibers are stored. This is also the layer where sensory nerves are stored to provide sensation.

Epidermis: This is the outermost layer of the skin. It contains the stratum germaninativum and stratum corneum layers. The stratum germaninativum is the lower section that produces cells while the stratum corneum layer is the outer layer which is serves as the protective surface. The epidermis also produces melanin.

Skin Colors

Skin colors are determined by the amount of melanin. Melanin is a dark pigment that gives skin darker tones. The more melanin there is in the skin, the darker it becomes. Production of melanin is stimulated when UVB rays cause DNA damage. Melanin is an excellent photoprotectant which prevents further harmful UV rays from causing skin cancer.