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3.1 Guiding Questions (602)

Terms in this set (11)

What are the 5 qualitative responses to physical stress?
death
injury
increased tolerance
maintenance
decreased tolerance
Level of physical stress exposure:
magnitude (high, low, moderate)
time - duration, repetition, rate
direction - tension, compression, shear, torsion
Clinically significant injuries
damages that are felt that cause notable dysfunction
In the physical stress model proposed by Mueller, do injured tissues always have the potential to return to maintenance range?
No, not all injured tissues always have the potential to return to maintenance range because if they are put under too much physical stress or not enough physical stress then they lose their ability to adapt and it causes cell death.
- put too far into plastic range
If there is reduced oxygen tension at the site of inflammation, how does this affect the healing of tissue
Reduced oxygen tension at the site of inflammation inhibits fibroblasts migration and collagen synthesis, decrease in tensile strength of skin, increase in susceptibility of infection.
What are the 5 cardinal signs of inflammation?
Erythema - increased vascularity (redness)
Heat - increased vascularity
Edema - extra interstitial fluid
Pain - pressure and chemical irritation
Loss of function
What does the hemostatic response within the inflammatory phase of tissue healing consist of? Under what circumstances does a hemostatic response occur?
- main funx: Coagulation, initiation of healing cascade
- characteristics: Bleeding, pain, clotting
- Occurs when there is vessel damage
- Controls blood loss
- Platelets: bond to expose collagen
+ fibrin deposition, +fibrin proliferation, +angiogenesis
- Fibrin released to stimulate clotting
- Form cross-links with collagen to form lattice that seals off vessels
What is granulation tissue? What are some of its characteristics?
Pink, berry-like textured - looks like little bubbles
Composed of new capillaries, fibroblasts, and myofibroblasts
Occurs during proliferation phase
As granulation tissue increases, fibrin clot decreases
Type III collagen starts converting to Type I (~ Day 12)
Still only 20% of normal tensile strength at Day 21
Reaches 80% of normal at ~6 weeks
still pretty weak, wound still vulnerable to injury
At what stage of healing is Type III collagen produced and approximately what is the tensile strength of uninjured tissue?
Early proliferation phase
Limited tensile strength (15-20% normal)
What are the effects of infection on tissue healing?
- infection accounts for 50% of complications of wound healing
- infections affect collagen metabolism → reduces collagen production and increases lysis which prevents and delays healing
excessive granulation tissue formation
What is chronic inflammation
- Inflammatory process
- Normal acute inflammation: <2 weeks
- Subacute inflammation: > 4 weeks
- Chronic inflammation: months to years
- chronic wounds- anything more than 3 months
- Persistence of injurious agent
- Interference with healing process (delayed)
- Immune response to foreign material
- Autoimmune disorder
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