The basic principles of wound healing in the skin involve a series of biological events aimed at repairing damaged tissue and restoring skin integrity.
These can be divided into four overlapping phases:
1. Hemostasis (wound healing):
Immediate Response: Occurs immediately after injury to stop bleeding.
Clot Formation: Blood vessels constrict, platelets aggregate to form a platelet plug, and fibrin stabilizes the clot to prevent further blood loss.
2. Inflammation:
Early Phase: Begins shortly after injury and lasts for several days.
Immune Response: Blood vessels dilate, increasing blood flow and attracting neutrophils and macrophages to the wound site. These cells remove debris, release growth factors, and help prevent infection.
3. Proliferation:
Tissue Formation: Lasts for several days to weeks.
Key Events:
Angiogenesis: New blood vessels form to supply nutrients and oxygen.
Fibroblast Proliferation: Fibroblasts produce collagen and elastin, strengthening new tissue.
Epithelialization: Epithelial cells migrate and cover the wound, restoring the skin barrier.
Contraction: Myofibroblasts pull wound edges together, reducing wound size.
4. Remodeling:
Long-term Phase: Can last for months to years.
Tissue Maturation: Collagen fibers realign, excess cells and vessels are removed, and the scar tissue strengthens, though it never fully regains original skin strength and elasticity.
These phases ensure effective wound repair, maintaining skin function and protection.