What are the stages of wound healing?

The answer

Wound healing proceeds through four overlapping phases. Hemostasis (seconds to hours) involves platelet aggregation and a fibrin clot forming a temporary barrier. The inflammatory phase (hours to days) brings neutrophils and macrophages that clear debris, kill bacteria, and release growth factors. The proliferative phase (days to weeks) features fibroblasts depositing collagen, new blood vessels forming through angiogenesis, and epithelial cells migrating across the wound bed to close the surface. The remodeling phase (weeks to years) involves gradual reorganization of collagen fibers from a disorganized lattice to a more structured alignment, with wound strength eventually reaching about 80% of original tissue strength. This process requires precise coordination among over 100 growth factors, cytokines, and cellular types; disruption at any stage leads to impaired healing, chronic wounds, or excessive scarring.