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67 Cards in this Set
- Front
- Back
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Wound healing by first intention? (3)
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1. Wound edges put together
2. Heals primarily by cell migration & proliferation 3. No inflammation or granulation tissue |
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Wound healing by second intention? (4)
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1. Inflammation
2. Granulation 3. Re-epithelialization 4. New matrix formation |
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When do wounds heal by second intention?
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If wound is full thickness of skin or enough tissue is damaged or lost that edges cannot be brought together
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Early phase of inflammation of healing by 2nd intention lasts how long?
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About 2 days
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Late phase of inflammation of healing by 2nd intention occurs when?
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Day 1- Day 7
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When does matrix formation begin & end?
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About Day 4- Day 30
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What happens during early phase of inflammation?
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1. Extravasation & clot formation
2. Infiltration of neutrophils |
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Platelets enter wound area, are exposed to collagen and release? (3)
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1. Fibrinogen
2. Von Willebrand factor VIII 3. Thrombokinase |
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Fibrin formation is initiated by?
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Thrombrin --> Cleaves fibrinogen into polypeptides
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Function of factor XIII?
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From cross link in fibrin
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Function of fibrin in clot?
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Acts as scaffolding for cells to move in & through the clot
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What forms the granulation tissue? (2)
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FIbroblasts
Endothelial cells |
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Once fibrin clot is formed what happens?
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Platelets release growth factors
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Substances released from damaged cells, platelets & protein fragments cause? (5)
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1. Vascular dilation
2. Increased capillary permeability 3. Cell attraction & migration 4. Cell differentiation 5. Enzymes release additional growth factors & cytokines |
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First cells to arrive at wound area?
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Neutrophils
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Function of neutrophils? (3)
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1. Kill & remove bacteria
2. Remove debri 3. Release enzymes & O2 radicals |
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What stimulates & attracts neutrophils? (4)
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1. Platelets release
- PDGF - TGFα - TGFβ 2. Broken collagen |
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Which cytokines are produced by neutrophils? (3)
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1. TNFa
2. IL-1 3. IL-4 |
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What happens during the late phase of inflammation? (3)
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1. Monocytes differentiate into macrophages
2. Fibroblasts differentiate into myofibroblasts 3. Lymphocytes migrate into wound area |
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What do monocytes do during late phase of inflammation? (3)
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Monocytes --> Macrophages
1. Continue removal of bacteria & debri 2. Phagocytose neutrophils 3. Release factors to promote granulation tissue formation |
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Granulation tissue is composed of? (6)
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1. Macrophages
2. Myofibroblasts 3. Leukocytes 4. Neutrophils 5. Large number of capillaries 6. Very hydrated ECM |
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ECM of granulation tissue has? (2)
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1. Type III collagen
2. Hyaluronan |
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What is fibroplasia?
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Proliferation, differentiation & contraction of fibroblasts
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Does granulation tissue have nerve endings?
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No
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What stimulates endothelial cells to proliferate & form capillary buds? (2)
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1. FGF
2. VEGF from macrophages |
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There is increased synthesis of VEGF during?
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hypoxia
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Endothelial cells in capillary buds secrete ____ to allow them to move through wound matrix?
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Proteases
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What stimulates protease secretion? (4)
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1. bFGF
2. TGFb1 3. IL-1 4. TNF-alpha |
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High concentractions of PDGF & bFGF stimulate?
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Chemotaxis
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Capillary cells attach to _____ & become functional capillaries?
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granulation tissue ECM
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What stimulates myofibroblast multiplication?
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PDGF
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What stimulates collagen synthesis by myofibroblasts & fibroblasts?
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TGF-beta
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Wound contraction (4)
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1. Actin filaments form & align w/ long axis of fibroblasts
2. Myosin molecules associate w/ actin 3. Actin filaments attach to extracellular collagen 4. Myoblasts communicate for synchronized contraction |
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How are actin filaments attached to extracellular collagen? (2)
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1. Integrins
2. Fibronectin |
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Myoblasts communication w/ each other by?
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Gap junctions
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Myofibroblasts align in which direction?
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Perpendicular to wound edges
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What is wound contraction?
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Myofibroblasts contract as unit, decreasing size of wound
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How are normal CT cells different from wound CT cells?
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Normal connective tissue cells don't have large amount of actin filaments & gap junctions
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DNA synthesis in epithelial cells around wound occurs ?
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about 12 hrs later
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Epithelial cells in germinal layer of skin start dividing when?
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24 hours later
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What happens to epithelial cells immediately following wound?
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Release attachments to each other & basement membrane --> become motile
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Epithelial cells form temporary attachments to?
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Fibronectin of granulation tissue & crawl over granulation tissue to cover wound
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If a scab forms what do endothelial cells do?
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Migrate under scab until surface is adequately covered
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DNA synthesis in CT begins ___ after injury?
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24 hours
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What is formed in early stage of ECM formation? (3)
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1. Hyaluronan (non-sulfated GAG)
2. Fibronectin 3. More type III collagen |
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Function of hyaluronan? (3)
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1. Very hydrated
2. Decreased cell attachment 3. Increased cell motility |
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Function of fibronectin in ECM formation? (2)
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1. Cell attachment
2. Substrate for cell migration |
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What is secreted during late stage ECM formation? (2)
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1. Mainly sulfated GAG
2. Mainly Type I collagen |
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Wound strength in skin is 20% of pre-wound strength by?
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3rd week
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After complete wound healing strength will reach what percentage of pre-wound strength?
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70%
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Which type of collagen has larger bundles & increased crosslink formation?
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Type I
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Why is exercise to wound area important?
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Applying forces increases wound strength at faster rate
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What are alternate pathways following injury? (4)
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1. Suppurative (pus)
2. Fibrosis 3. Chronic inflammation 4. Extensive formation & presence of granulation tissue (hypergranulation) |
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Causes of chronic inflammation? (7)
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1. Infection
2. Foreign particles 3. Autoimmune diseases 4. Chronic irriation or excessive pressure 5. Poor circulation to area 6. Excessive movement 7. Drugs (corticosteroids) |
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Examples of artificial ECM wound dressings? (2)
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1. Duradurm
2. Hydragran |
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Benefit of hydragran?
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Mix w/ water--> forms ECM-like gel
Prevents dehydration & maintains environment for synthesis of new ECM |
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Disadvantage of hydragran?
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Lets O2 into wound area
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Faster healing if dressing is used that ? (2)
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1. Keeps wound moist
2. Scab formation prevented-- slower if epithelial cells have to crawl under scab |
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If broken end of bone are smooth & set together w/ 1 mm or less space between bone will heal by?
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Remodeling & little or no callus type tissue forms
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When bones are broken & ends are ragged?
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Callus forms around & between ends
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Following formation of granulation tissue in bone repair what occurs? (2)
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1. Granulation tissue becomes denser --> forms callus
2. Fibrocartilage forms in callus |
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Callus formation is important in bone repair for?
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Stabilizing bone
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Bone beings to form where in bone fracture repair?
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Within callus
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What happens to rough or uneven pieces of bone protruding out from bone surface (non-functional bone)?
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Gradually resorbed
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Does a typical scar occur w/ bone repair?
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No
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Why do 30% of immature teeth fracture after avulsion w/ endo treatment? (2)
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1. Open apices
2. Thin root dentin |
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Better goal for avulsion of immature tooth? (3)`
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1. Replantation
2. Pulp regeneration 3. Reattachment of PDL |
