Some of the most important skin functions are listed below(2017a).

  1. Protects from mechanical damage, elastin allows skin reformation after deformation, subcutaneous fat allows to absorb shock.
  2. Because skin is a poor conductor of heat it protects against heat damage to internal organs and help to regulate temperature.
  3. First line of defense against microbes. Skin protects against all microbes. Sebum protects against overgrowth of bacteria.
  4. Keratinocytes protect against chemicals.
  5. Superficial layers of epidermis and presence of hair protects the dividing basal cells in the stratum basale.
  6. Helps to regulate skin temperature by sweat glands and in permeation by absorbing water in sebum.
  7. Helps to excrete waste products and salt in sweat.
  8. Helps in synthesizing Vit D and other structural proteins used immediately after injury or regular repair of skin.
  9. Acts as a sensory organ for temperature, pain, touch, vibration and pruritus.
  10. Helps to protect against sun by increasing or decreasing melanin pigment.

References:

2017a. Functions of the skin CME | DermNet New Zealand. Available at: https://www.dermnetnz.org/cme/principles/functions-of-the-skin/.