WOUND HEALING- Complication, Factors & Strength 

The Phases of Wound Healing

1. Inflammatory phase
2. Proliferation phase
3. Maturation phase

• The inflammatory phase is the body’s natural response to injury. After initial wounding, the blood vessels in the wound bed contract and a clot is formed. Ihe predominant cells at work here are the phagocytic cells; neutrophils and macrophages, mounting a host response and autolysing any devitalised necrotic / sloughy tissue.
• During prollferation, the wound is ‘rebuilt’ with new granulation tissue which is comprised of collagen and extracellular matrix and into which a new network of blood vessels develop, a process known as ‘angiogenesis’.
• Healthy granulation tissue is dependent upon the fibroblast receiving sufficient levels of oxygen and nutrients supplied by the blood vessels. Healthy granulation tissue is granular and uneven in texture; it does not bleed easily and is pink / red in colour.Epithelial cells finally resurface the wound, a process known as’epitheialisation’.
• Maturation is the final phase and occurs once the wound has closed. This phase involves remodelling of collagen from type III to type I Cellular activity reduces and the number of blood vessels in the wounded area regress and decrease.
• “Proliferative phase: Approximately 80% of the collagen in normal skin is type I collagen; the remaining is mostly type III.
• In contrast, type III collagen ls the primary component of early granulatlon tissue and is abundant in embryonic tissue. Collagen fibers are deposited in a framework of fibronectin’

Complications of Wound Healing-

• Infections
• Epidermal cyst
• Deficient scar formation
• Incisional hernia
• Hypertrophied scar
• Keloid formation
• Excessive contraction

Wound Strength-

• Wound contraction- completed by 14^th day
• At the end of 3^rd month 70- 80% of normal skin (maximum strength) 

Extracellular Matrix-

• It has 5 major components

1. Collagen
2. Glycoproteins
3. Basement membrane
4. Elastic fibres
5. Proteoglycan 

• Fibroblasts in healing wound are derived from local mesenchyme.
• Vitamin C promotes wound healing.
• Vitamin E inhibits wound healing