Wound Healing PATHO Flashcards
Four stages of wound healing
Hemostasis, inflammatory, prolifertive, remodelling
Hemostasis
The body’s response to the loss of blood and the compromisation of the epithelial barrier. Vasoconstriction occurs to minimise bleeding and a blood clot is formed. A protein called fibrin forms a fibrous mesh that impedes the flow of blood, preventing bacteria from getting in
Inflammatory
The body secrets white blood cells called macrophages to fight any pathogens that may have gotten through which engulf bacteria and damaged tissue. These cells secrete growth factors and proteins that attract immune system cells to the wound to facilitate repair. The blood vessels now expand through vasodilation.
Proliferation
Fibroblast cells enter the wound and produce collagen, which forms connective skin tissue. Epidermal cells divide to reform the outer layer of skin, the dermis contracts to close the skin. The epidermis meets and grows upwards until full thickness is restored. Any bacteria is continued to be removed by phagocytes, and the clot above the new tissue becomes a scab
Remodelling
The collagen is rearranged and converted into specific types, making the tissue and blood vessels stronger. The tissue is gradually replaced by scar tissue.
Four stages of inflammation
Recognition, recruitment, removal and repair
Recognition
A sentinel cell recognises the damage and releases cytokines. White blood cells are brought to the site of inflammation.
Recruitment
Endothelial retraction allows more leukocytes to reach the site of inflammation. Water is brought into the tissue to bring about swelling.
Removal
Macrophages and neutrophils phagocyte pathogens and damaged cells in the tissue
Repair
The white blood cells release cytokines such as fibroblasts and growth factors to initiate the repair of damaged tissues.
