Physiological functions of the skin

1. Sensory
 * Tactile: mechanoreceptors
 * Thermal: thermoreceptors

2. Mechanical injury protection
 * nails

3. Vit D3 synthesis

4. Radiation injury prevention
 * Physical: barrier for α-radiation
 * Chemical: melanin for UV radiation

5. Thermoregulation
 * hair
 * perspiration
 * vascular involvement

6. Antimicrobial properties
 * sebum from sebaceous glands

7. Fluid loss prevention

8. Physical barrier
 * Physical: keratin filaments
 * Immunological: Langerhans cells in epidermis and macrophages and mast cells in dermis