Wound Healing (VanBeek) Flashcards
Which of these is NOT a stage of wound healing?
A. hemostasis & inflammation
B. granulation & proliferation
C. remodeling & maturation
D. evaporation & condensation
That’s right smarty pants, D!
Remember? It was part of your 3rd grade science unit about water. And at the time, it and long division were ruining your life, just like derm is ruining your life now. But see how well you’re doing?! No need to panic. You’re gonna make it through this one too!
Which of the following statements about hemostasis is FALSE?
A. Hemostasis is the shortest phase of wound healing, lasting about 2-5 days.
B. Initially, inflammatory mediators cause vasodilation to encourage the migration of leukocytes to the site of injury, after which comes prompt vasoconstriction and clot formation.
C. Exposed collagen plays an important role in activating the clotting cascade.
D. Redness, heat, and swelling are visible indicators of the immune response and occur during the hemostasis phase of wound healing.
E. Local histamine release causes capillary vasodilation at the site of injury.
B.
This is backwards. The initial response following injury is vasoconstriction and clot formation to slow blood loss. Once platelets degranulate, vasodilatation and capillary leak occur to allow serum and leukocytes into the field of injury.
these 2 potent vasoconstrictors are released from damaged cell membranes following an injury
thromboxane A2 and prostaglandin 2A
these cells are the first responders to the site of injury, and secrete substances that promote vasoconstriction, clotting, and recruitment of leukocytes
platelets
substance that leaks from damaged tissues causing platelets to aggregate and adhere to exposed collagen of the damaged vessel
ADP (adenosine diphosphate)
the _____ mesh strengthens the platelet aggregate into a stable hemostatic plug/clot
fibrin
this cytokine facilitates PMN migration from surrounding blood vessels
TGF-ß
these are the first leukocytes to migrate to the wound, providing the earliest proinflammatory cytokines, and peaking in number in 24-48 hours
neutrophils
*responsible for:
- scavenging bacteria and debris
- complement-mediated opsonization of bacteria
- destruction of bacteria via oxidative burst mechanisms
About 2-3 days after the wound occurs, these cells begin to enter the wound site, marking the onset of the proliferative phase even before the inflammatory phase has ended.
fibroblasts
*this is clinically manifest by pebbled red tissue in the wound base.
in response to chemical signals generated by a wound, fibroblasts deposit a sticky bed of proteins including _____, which helps them move in and stick to the wound bed
laminin 5
why is redundancy important in the wound healing process?
redundancy helps compensate for genetic defects in which a component may become knocked out and unable to perform its role
Which of the following statements regarding the proliferative/granulation phase is FALSE?
A. Cell migration is facilitated by hyaluronic acid
B. Matrix metalloproteinases are enzymes involved in cleaving paths throughout the wound mesh to make room for new tissue
C. Fibroblasts have migrated into the wound and begun laying down new collagen by days 5-7
D. Early in normal wound healing, type I collagen is layed and later is replaced by stronger type III collagen
E. TIMPs play an important role in regulating tissue destruction
D.
Type III collagen is laid first and is replaced by the stronger type I collagen later.
Which of the following is not an important part of angiogenesis?
A. New vessel formation is stimulated by high lactate, high pH and low tissue oxygen.
B. The formation of new blood vessels requires extracellular matrix and basement membrane degradation.
C. Pericytes regenerate the outer layers of capillaries while endothelial cells produce the lining.
D. Multiple cytokines play a role in angiogenesis.
E. In the earliest part of angiogenesis, small blind loops of capillaries or “sprouts” form.
A
New vessel formation is stimulated by high lactate, low (or acidic) pH, and low tissue oxygen.
although collagen content is maximal at 3 weeks, its breaking strength is only ____% of baseline (tell your patients after they get their stitches out!)
15%
At its maximum strength (12 weeks), scar tissue is only about ___% as strong as the original tissue, and is majorly composed of collagen type ___.
80%; type I
