The physiological functions of the skin are:
The skin protects the body from physical, chemical and biological threats (microorganisms, UV radiation, etc.).
It is a sensory organ with sensory receptors.
Via sweat secretion and modulation of cutaneous microcirculation.
It synthesizes vitamin D in the presence of sunlight.
Skin is also a secretory organ. It secretes sweat and sebum.
The skin is divided into three layers:
the Epidermis (or outermost layer) for protection and hydration
the Dermis for maintenance and elasticity
the Hypodermis (or subcutaneous tissue) for energy.