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4 stages to tissue response
- 1. cellular injury
- 2. altered metabolism
- 3. chemical reaction
- 4. inflammatory response
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Healing response-continuum
- inflammatory response (0-4d)
- repair and regeneration (2-52d)
- maturation-remodeling (21-2yr)
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inflammatory response phase includes:
- 1.vascular response
- 2.chemical cellular response
- 3.hemostatic response
- 4.immune response
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1.Vascular response
- changes in blood flow
- increased capillary permeability
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2.Chemical response
- sets stage for repair
- 3 important mediators
- histamine-vasodilation, increase cell permeability
- leukotrienes-vasodilation
- cytokines-regulate leukocytes
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3.Hemostatic Response
- blood vessels retract and seal off
- venous and lymphatic drainage blocked
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2. cellular response
- platlets and leukocytes move from centre vessel to wall
- chemotaxis--injury site (6hrs)
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clot formation begins ____ hrs and ends _____hrs
12, 48
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whats the process from and injury to clot formation
injury---cmeical mediator released---vascular reaction--platlets and leukocytes stick to vascular wall--phagocytosis--clot formation
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4.Immune response
- bacteria damage infections
- removal of toxins
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fibroblastic repair stage (scar formation)
- temporary repair
- wound contraction
- revascularization
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damaged tissue replaced by cells of same type_____
regeneration
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original tissue is replaced by scar tissue______
repair
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repair phase
- regeneration of capillary buds
- formation granulation tissue
- formulation extracellular matrix
- tensile strength of scar increases, # of fibroblasts decreases=beginning of maturation phase
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maturation-remodeling phase
- long term
- balance between breaking down and growing
- remodeling of collagen fibres
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healing by first intention, closely opposed edges--> ↓granulation tissue is ______
primary healing
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healing by secondary intention, gaping wound--> ↑granulation tissue, ↑scar
secondary healing
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what are six factors that affect healing?
- 1. extent of injury
- 2. poor vascular supply
- 3. medication
- 4.infection
- 5. humidity
- 6. health, age and nutrition
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which tissue type has limited healing capacity
cartialge
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which tissue type can scar and regnerate?
liament
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what is the healing property of epithelium tissue?
great potential to regenerate
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what is the healing property of msucle?
optimal regeneration dependent on multiple factors
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what type if tissue requires right amount of collagen to heal
tendon
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chronic inflammation
- low concentration chemical mediators
- production granulation tissue and fibrous connective tissue
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what are three dimensions of pain perception and explain
- sensory-check source of pain
- cognitive-relate to past experiences
- affective-fear, anxiety, crying
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explain how pain response works
injury-->activation PNS-->actication CNS-->send pain signal to brain-->PAIN
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what are diferent types of pain receptors?
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A-delta
- lightly myelinated, afferent
- activated by high pressure or temp
- fast
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C fibres
- unmyelinated afferent
- not as intense
- slower onset
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Acute pain
- A-delta fibre activation
- intense sharp burning pain
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chronic inflammation
- C fibre stimulation
- dull throbbing pain
- pain thay still occurs long after healing process completed
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referred pain
- visceral, deep mm
- due to embryo migration before birth
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Gate theory
- modulated by spinal cord
- stimulation of A-Beta reaches spinal cord-->causing "closing of gate"
- tricks brain into not feeling pain because cannot be interpreted by cortex
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describe descending pain control
- transmit impulses from cortex to spinal cord
- release of neurotransmitters blocks and inhibit ascending neurons
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B-Endorpin theory
- modulated by cerebral cortex or higher centers
- descending pain relief
- endorphins released by hypothalmus into blood or CSF
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