BIOM20001 Lecture Notes - Lecture 64: Proteoglycan, Serous Membrane, Collagen
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Involves epithelial regeneration and connective tissue scar (repair)
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2 types of wounds severity leading to:
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Focal disruption of epithelial basement membrane
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Relatively little cell death
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Small scar, minimal wound contraction
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e.g. Surgical incision, paper cut
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Barrier to invading organisms
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Prevents loss of tissue fluid
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First thrombosis (scab) forms at cut
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Neutrophils
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Exudate (could have pus)
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Inflammaion will occur if there is infection or not due to damaged tissue
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Labile epithelial cells migrate and proliferate
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Form a thin epithelial layer beneath the scab. Use scab as a guide
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Regeneration
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Neutrophils largely replaced by macrophages, which clear debris and elaborate
mediators that facilitate repair
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Healing by first intention: small disruption
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Cutaneous wound healing
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mediators that facilitate repair
Angiogenesis
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Fibroblast (spindle shaped cells) recruitment and activation
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They form new stroma (ECM components: proteoglycans, glycoprotens, collagen
type III which forms scar)
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Formation of granulation tissue in response to mediators
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Collagen accumulation
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Type I collagen (thicker and stronger)
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Leukocyte infiltrate and edema decrease. Inflammatory response dampens
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Vascularity decreases
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Wound strength increases
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Scar formation
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More extensive cell loss (ulcer, asbscess, infarction of parenchyma tissue)
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Larger clot, more inflammation
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More granulation tissue forming underneath clot
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Epithelial cells have a wider area to migrate across. Takes longer
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Healing by second intention
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Document Summary
Involves epithelial regeneration and connective tissue scar (repair) Small scar, minimal wound contraction e. g. surgical incision, paper cut. Inflammaion will occur if there is infection or not due to damaged tissue. Form a thin epithelial layer beneath the scab. Neutrophils largely replaced by macrophages, which clear debris and elaborate mediators that facilitate repair. Formation of granulation tissue in response to mediators. They form new stroma (ecm components: proteoglycans, glycoprotens, collagen type iii which forms scar) More extensive cell loss (ulcer, asbscess, infarction of parenchyma tissue) Epithelial cells have a wider area to migrate across. Wound contraction: drawing together of sides of a wound. Myofibroblasts (modified fibroblast with smooth muscle cell like properties) mediate this process. They migrate into wound and contract, to reduce the size of wound. Serosal surface inflammation (organization of exudate - fibrous scar). If this cannot be cleared then you get fibrous scar tissue formation which can compromise function.
