Protective Functions at a Glance
The skin protects the organism from mechanical, microbial, chemical and physical influences.
| Damaging influence | Protective mechanism |
|---|---|
| Mechanical influences | Thickening of the horny layer (callus formation) , elasticity of the dermis and subcutaneous fatty tissue (i) |
| Alkaline noxae (i) | Buffer capacity of the hydrolipid film and protective acid mantle (i) |
| Penetration of skin bacteria and Harmful substances |
Protective acid mantle, permeability barrier (i) of the horny layer |
| Dehydration | Epidermal lipids, hydrolipid film, natural moisturizing factors (i) (NMF) |
| UV radiation | Increased melanin formation, thickening of the horny layer |
| Heat | Perspiration, widening of the vessels in the skin |
| Cold | Narrowing of the vessels in the skin |
Passive and active functions of the skin:
- Protection from cold, heat, radiation
- Protection from pressure, blows, abrasion
- Protection from the action of chemical substances
- Protection from invasion by microorganisms (formation of the protective acid mantle (i))
- Protection from heat and water loss
- Defence against invading microorganisms
- Absorption of certain substances
- Perspiration (cooling)
- Circulatory and thermal regulation by means of the dermal vascular system
- Pressure, vibration, tactile, pain and temperature sensory organs
Summary:
Several systems present in the skin contribute to the protective function of the skin. The corneocytes combine with the epidermal lipids (brick and mortar model) to form what is known as the permeability barrier (i). The skin surface lipids have an antibacterial and fungicidal effect. With its physiological pH (i) of approximately 5.5 the protective acid mantle (i) protects the skin from microbial invasion and alkaline noxae (i).
