Wound Healing Flashcards
T/F: Clean-contaminated wounds are open, acute, accidental, or surgical wounds in which there has been a major break in sterile technique.
False; Clean-contaminated wounds are surgical wounds in which the respiratory, alimentary, or urogenital tracts are entered under controlled conditions without unusual contamination, whereas contaminated wounds are open, acute, accidental, or surgical wounds in which there has been a major break in sterile technique.
T/F: Dirty or infected wounds are those that are old, have devitalized tissue, or have gross contamination with foreign debris.
True
Clean, clean-contaminated, and contaminated wounds by definition contain less than ________ bacteria per gram of tissue.
1 × 10^5
A type of injury occurring when the body part is subjected to a high degree of force between two heavy objects.
Crush
A type of injury involving a blow to the skin in which blood vessels are damaged or ruptured.
Contusion
A type of injury involving damage to the skin epidermis and portions of the dermis by blunt trauma or shearing forces.
Abrasion
A type of injury involving loss of skin or tissue characterized by tearing of the tissue from its attachments.
Avulsion
A type of injury involving a wound created by a sharp object that has minimal adjacent tissue damage.
Incision
A type of injury involving an irregular wound created by tearing of tissue. Skin and underlying tissue damage can be variable.
Laceration
A type of injury involving a penetrating injury to the skin resulting in minimal skin damage and variable underlying tissue damage. Contamination with dirt, bacteria, and hair is common.
Puncture
Immediate suture closure without tension of a clean or clean-contaminated wound converted to clean wound.
Primary closure
Which of the following statements defines secondary closure of a wound?
- Immediate suture closure without tension
- Performed 2-5 days after injury; tissue débridement and wound lavage before closure
- Performed at least 5 days after injury; granulation tissue and epithelialized skin edges excised at the time of closure
- Healing by granulation tissue, wound contracture, and epithelialization
Secondary closure = Performed at least 5 days after injury; granulation tissue and epithelialized skin edges excised at the time of closure
What closure would you select for a clean or clean-contaminated wound converted to clean wound?
Primary closure; immediate suture closure without tension
What closure would you select for a clean-contaminated or contaminated wound with questionable tissue viability, edema, skin tension?
Delayed primary closure performed 2-5 days after injury; tissue débridement and wound lavage before closure
What closure would you select for a contaminated or infected wound?
Secondary closure performed at least 5 days after injury; granulation tissue and epithelialized skin edges excised at the time of closure
What closure would you select for a large skin defect and/or extensive tissue devitalization?
Second intention healing Wound tissue is unsuitable for closure; Healing by granulation tissue, wound contracture, and epithelialization
This phase in wound healing involves hemostasis and inflammation, is a very metabolically active period lasting for several days, during which wound healing is jump started.
Inflammatory or lag phase
Reflex vasoconstriction occurs by smooth muscle contraction mediated by release of _________ and _____________ from the injured vessels and platelet-derived __________. The response is transient, lasting only ___ to ___ _______, after which vasodilators such as _________, __________, and _______ _______ predominate, facilitating diapedesis of cells, fluid, and protein into the wound and extracellular space.
endothelin and thromboxane A2; serotonin; 5 to 10 minutes; prostacyclin, histamine, and nitric oxide
T/F: Hemostasis during the lag phase is ultimately achieved through compression of vessels by soft tissue swelling and formation of a fibrin-platelet plug within the wound defect.
True
The activated platelets within this fibrin plug amplify the early inflammatory phase of healing through the release of wound repair mediators, most importantly_______-______ ________ ______ and ________ _______ _______-_______, from their storage granules.
platelet-derived growth factor (PDGF); transforming growth factor beta (TGF-β)
________________ ______ are the first cell type to enter the wound in large numbers. They appear soon after injury, with numbers peaking on about day 2, and decline as debris is cleared from the injured site.
Polymorphonuclear cells (PMNs, neutrophils)
The principal degradative proteinases released by PMNs to remove damaged tissue include __________, neutrophil-specific __________ ________, and neutrophil ________.
cathepsin G; interstitial collagenase; elastase By 24 hours, circulating monocytes begin to enter the wound and differentiate into macrophages
By ______ after injury, circulating monocytes begin to enter the wound and differentiate into macrophages.
24 hours
What are the proteinases released by macrophages that aid in wound debridement?
elastase, collagenase, and plasminogen activator
T/F: Macrophages may be present for a period lasting from a few days to weeks, depending on wound characteristics. Their synthesis and release of tissue growth factors initiates the proliferative phase of the repair process, including angiogenesis, fibroplasia, and epithelialization.
True
T/F: Neutrophil and macrophage apoptosis occurs as the inflammatory phase subsides.
True
The _________ phase of acute tissue repair is active by the ____ day following injury. It is characterized by angiogenesis, fibrous and granulation tissue formation, collagen deposition, epithelialization, and wound _________.
proliferative; third; contraction
T/F: Decreased oxygen tension, high lactate levels, and low pH within the wound initiate the process of angiogenesis.
True
T/F: The endothelial cells at the tips of capillaries adjacent to the wound grow in response to cytokines released by platelets and macrophages at a rate of 1.0 to 2.0 mm per day.
False; The endothelial cells at the tips of capillaries adjacent to the wounded area are attracted to the area by fibronectin, found within the provisional matrix, and grow in response to cytokines released by platelets and macrophages at a rate of 0.4 to 1.0 mm per day.
T/F: Fibroblasts begin to arrive by the fifth day after injury.
False; Fibroblasts begin to arrive by the second day after injury, and by the fourth day they are the major cell type in the wound bed. Peak in fibroblast numbers is at 7 to 14 days after injury.
Multiple cytokines are involved in wound repair. Which one of the following cytokines induces the differentiation and maturation of hematopoietic stem cells?
- vascular endothelial growth factor (VEGF)
- interferon (IFN)
- colony-stimulating factor (CSF)
- tumor necrosis factor
colony-stimulating factor (CSF)
Fibroblast migration into the wound and their subsequent proliferation is largely regulated by ________, _________ and __________.
Platelet-derived growth factor (PDGF); Transforming growth factor-β (TGF-β); Basic fibroblast growth factor (bFGF)
T/F: Fibroblasts synthesize and release collagen; glycosaminoglycans, including hyaluronan (which facilitates cell migration); glycoproteins (fibronectin and laminin); and proteoglycans.
True
T/F: Fibroblasts secrete proteases, including MMPs, which digest the fibrin clot so that replacement with the new components can occur.
True
Collagen production begins slowly on the ___________ after wounding and reaches peak production within __________.
second or third day; 1 to 3 weeks
T/F: Wound fibroblasts produce type II collagen.
False; although wound fibroblasts produce type I collagen, which predominates in unwounded dermis, almost 30% to 40% of the collagen found in the acute wound will be type III (blood vessels).
Type I collagen = bone, tendon, skin (fibroblasts)
Type II collagen = cartilage
Type III collagen = blood vessels
T/F: Fibroblasts within the wound organize the collagen molecules into bundles, which are aligned perpendicular to the wound surface.
False; fibroblasts within the wound organize the collagen molecules into fibers and then into bundles, which are aligned parallel to the wound surface, usually along lines of maximum tension. The presence of collagen and its arrangement contribute to tissue strength.