Wound Healing

From Anvita Health Wiki

Introduction

• Restoration of integrity to an injured tissue.

• 3 phases of wound healing:

• initial tensile strength

• hemorrhage into tissue
• formation of a fibrin clot
• fibronectin in extravasated plasma is cross-linked to extracellular matrix components ( fibrin, collagen) by transglutaminases

• remodelling

• phagocyte ( neutrophil, macrophage) recruitment
• proteolysis & phagocytosis
• temporary matrix formation from blood proteins

• proteoglycans
• glycoproteins
• type 3 collagen
• fibronectin

• definitive scar

• proliferation

• fibroblasts
• endothelial cells
• smooth muscle

• granulation tissue
• wound contraction
• definitive matrix

• type 1 collagen

• 2 forms of healing

• healing by primary intention

• wounds with apposed edges of healthy tissue
• minimal tissue loss
• requires minimal cell proliferation & neovascularization
• small scar
• for clean wounds

• healing by secondary intention

• wounds with separated edges of healthy tissue
• gouged wound, significant tissue loss, contaminated wound
• requires granulation tissue to heal

• wound contraction
• cell proliferation
• neovasculatization

• wound re-epithelialized from margins
• collagen fibers in granulation tissue
• granulation tissue eventually resorbed & replaced by scar tissue

More General Terms

• healing

References

Pathology, 2nd ed. Rubin & Farber (eds), JB Lippincott, Philadelphia, 1994, pg 81-92

wound healing