Wound Healing Flashcards
Healing
Processes by which the body repairs damage tissues after inflammation
Two principle of healing
Replacements by regenerated cells
Fibrous scar tissue
Three classic phases of healing and repair
Inflammation
proliferation
maturation
Factors affecting healing
Nature and magnitude of injurious agents
Ability of surviving cells to proliferates and repopulate tissue
Conditions that inhibit repair
Various diseases
Type of cells based on proliferative capacity
Permanent cells
labile cells
stable cells
Permanent cells
Static cell populations
No Proliferatibr capacity
Neurons , striated muscle , cardiac muscle
Labile cells
Renewing cell population continue to proliferate through adult life
Epithelial, lymphoid, haemopoietic
Stable cells
Conditionally renewing cells
Rapid proliferation only when cell loss
Hepatocytes, fibroblasts, endothelial cells , smooth muscles
Two types of skin wound healing
First intention
Second intention
Healing by first intention
Healing of a clean incised wound
very little tissue loss
minimal acute inflammatory exudate and necrosis
Wound edges apposed
Healing by second intention
Tissue loss
necrosis
defect large
edges not apposed
Require more hemorrhage, acute inflammation, exudate
more time to remove debris
More time for replacement by fibrous tissue
First intention healing pathogenesis
24h- Neutrophils appear at the margins
Enzyme released to digest clot
Mitosis of basal cells of epidermidis
Monolayer of basal cells fuse in the middle line in 48 hours
72h- Macrophages replace neutrophils
Fibrin strands with fibronectin chemotactic for macrophages and fibroblasts scaffold the cells
Macrophages remove cell debris , secrete growth factors, stimulate angiogenesis
Fibroblast mitosis release collagen one and three elastic fibers ground substance fibronectin
Granulation tissue appear with new vessels fibroblasts ground substance
Day5 - normal thickness of epidermis
Day 7 - epidermis differentiation
2nd week - less inflammation, edema , whitening of wound
2nd intention healing pathogenesis
Large wounds , infection margins separated
Same as in 1st
More damage.; inflammation, granulation
Epidermis thinner
Wound contraction to reduce wound by myofibriblasts
Factors affecting local wound healing
Blood supply Infection Mechanical factors Foreign body : sand, glass etc Size Shape Location
Factors affecting systemic wound healing
Nutrition Vit c def Zinc def Systemic disease Circulatory status Hormone therapy Temperature Systemic sepsis Age Obesity Uremia
