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27 Cards in this Set
- Front
- Back
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Types of Wound Healing
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Regeneration
Repair |
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Regeneration
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Damaged or lost cells are replaced by identical cells
Only certain tissues are capable; sometimes only parts of the tissues |
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Repair
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Replacing damaged tissue with a mass of fibrous connective tissue
Scar |
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Healing and Cell type
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Labile
Stable Permanent |
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Labile Cells
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Transitory, changeable
Proliferate throughout life i.e. skin, oral cavity, vagina, cervix |
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Stable Cells
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No high rate of replication but can proliferate under certain conditions
i.e. glandular organs, liver, kidney, pancreas, smooth muscles blasts and vascular endothelial cells |
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Permanent Cells
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Lose capacity for mitosis after birth.
i.e. nerve, skeletal, cardiac, lens of eye |
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Labile & Stabile Cells Regeneration
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Basement membrane must be untouched.
Damage: i.e. cirrhosis of the liver |
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Permanent cells and healing
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Scarring
Replacement tissue is not same as original function |
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Process of wound healing
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Fibrin of original clot stabilizes by being bound to fibronectin
**** chemotactic for macrophages and fibroblasts |
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Speed of Wound healing
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0-24 hours: fibroblasts & vascular endothelial cells start to proliferate around wound
3-5 days: granulation tissue appears- new small blood vessels and fibroblasts |
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Fibroblasts derivation
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Mesenchymal Elements
1. Undifferentiated stem cells of connective tissues 2. Phagocytic Histiocytes of the interstitium 3. Fibrocytes of the extracellular matrix |
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Granulation Tissue
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More cellular than ordinary connective tissue
Very leaky endothelial cells (creating edema) |
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Wound Contraction
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Myofibroblasts migrate to wound 2-3 days after injury
Actin & Myosin reduce size of original defect through contraction |
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Repair
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Fibroblasts activate to make and secrete components of extracellular matrix
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Extracellular Matrix components
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1. Collagens
2. Basement Membranes 3. Structural glycoproteins (fibronectin) 4. Elastin 5. Proteoglycans |
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Collagen in Wound Repair
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Days 1-7: type 3 collagen
After Day 7: Type 1 collagen *** continues to increase for 2-3 months before decline |
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First Intention Healing
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Edges of wound are closely apposed
Minor Scarring Sutures 48 hours: thin layer of epithelium 72 Hours: macrophages replace initial infiltration of neutrophils Day 5: granulation tissue fills wound with collagen |
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Second Intention Healing
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Cut edges are not close
No surgical intervention or just extensive tissue loss More granulation tissue required |
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Cicatrix/ Contracture
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Excessive contraction
Can be serious depending on location (joint, GI tract blocked) |
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Liver Healing
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Damage to basement membrane will result in cirrhosis.
If not, then regeneration |
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Kidney Healing
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Glomeruli- no regeneration
Medullary Tubules- partial Cortical Tubules: will regenerate fully as long as extracellular matrix is spared |
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Lung Healing
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Regenerates as long as basement membrane is fine
If BM is damaged may lead to functional lung tissue |
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Heart Healing
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No regeneation
Contraction is impaired |
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Nervous System Healing
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No regeneration
Gliosis- scarring in CNS |
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Bone Healing
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Complete regeneration
But fracture has to be immobilized properly, etc. |
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Soft- Tissue Healing
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Heal poorly b/c they are poorly vascularized
1 Week: minimal strength but tissue continuity Fibroblasts make type III collagen (reticulin) first. Followed by Type I (stronger) Scarring results if not moved/ treated with normal movements |
