Neraida Petrai

1. Introduction Skin is the largest organ in the human body, providing the first line of defense against external damage but also serving as a wall barrier against pathogen infiltration. Moreover, it plays a key role in many vital functions, such as immunological surveillance, preventing loss of physiological fluids, synthesis of vitamin D3, and temperature regulation. After a skin injury, the immune system is activated to heal the wound quickly and prevent bacterial contamination.