Wound Healing Phases

Wound healing is a natural physiological reaction to tissue injury. However, wound healing is not a simple phenomenon but involves a complex interplay between numerous cell types, cytokines, mediators, and the vascular system. The cascade of initial vasoconstriction of blood vessels and platelet aggregation is designed to stop bleeding. This is followed by an influx of a variety of inflammatory cells, starting with the neutrophil. These inflammatory cells, in turn, release a variety of mediators and cytokines to promote angiogenesis, thrombosis, and reepithelialization. The fibroblasts, in turn, lay down extracellular components which will serve as scaffolding.The inflammatory phase is characterized by hemostasis, chemotaxis, and increased vascular permeability, limiting further damage, closing the wound, removing cellular debris and bacteria, and fostering cellular migration. The duration of the inflammatory stage usually lasts several days.The proliferative phase is characterized by the formation of granulation tissue, reepithelialization, and neovascularization. This phase can last several weeks.The maturation and remodeling phase is where the wound achieves maximum strength as it matures.