Wound healing
In undamaged skin, the epidermis (surface layer) and dermis (deeper layer) form a protective barrier against the external environment. When the barrier is broken, biochemical events repair the damage. This process is divided into predictable phases: blood clotting (hemostasis), inflammation, tissue growth (proliferation), and tissue remodelling (maturation). Blood clotting may be seen as part of the inflammation stage instead of a separate stage.