Wound healing Healing

1 wound healing

1.1 clotting phase
1.2 inflammation phase
1.3 proliferative phase
1.4 maturation phase

wound healing

in response incision or wound, wound healing cascade unleashed. cascade takes place in 4 phases: clot formation, inflammation, proliferation, , maturation.

clotting phase

healing of wound begins clot formation stop bleeding , reduce infection bacteria, viruses , fungi. clotting followed neutrophil invasion 3 24 hours after wound has been incurred, mitoses beginning in epithelial cells after 24 48 hours .

inflammation phase

in inflammatory phase, macrophages , other phagocytic cells kill bacteria, debride damaged tissue , release chemical factors such growth hormones encourage fibroblasts, epithelial cells , endothelial cells make new capillaries migrate area , divide.

proliferative phase

in proliferative phase, immature granulation tissue containing plump, active fibroblasts forms. fibroblasts produce abundant type iii collagen, fills defect left open wound. granulation tissue moves, wave, border of injury towards center.

as granulation tissue matures, fibroblasts produce less collagen , become more spindly in appearance. begin produce stronger type collagen. of fibroblasts mature myofibroblasts contain same type of actin found in smooth muscle, enables them contract , reduce size of wound.

maturation phase

during maturation phase of wound healing, unnecessary vessels formed in granulation tissue removed apoptosis, , type iii collagen largely replaced type i. collagen disorganized cross-linked , aligned along tension lines. phase can last year or longer. scar made of collagen, containing small number of fibroblasts left.