wounds Flashcards
3 stages/phases of physiologic process of wound healing
- inflammatory or substrate
- proliferative
- maturation or remodeling
what basic physiologic process is common to all wounds
inflammation
cardinal signs of inflammation
redness (rubor), heat (valor), swelling (tumor), pain (dolor), and loss of function
trauma activates a cascade of chemoattractants (PDGFs and C5A) and mitogens that recruit
phagocytes, fibroblasts, and endothelial cells
when does the initial event of clotting blood and recruitment of cells occur after injury
first 1-2hrs
what are the first cells that enter the wound
platelets which come into contact w damaged collagen at time of injury
what happens when platelets contact the damaged collagen
platelets degranulate and release alpha granules that contain multiple growth factors, including PDGF and transforming growth factor beta (TGF beta)
what do cytokines and growth factors do
cytokines are soluble proteins that are secreted by a cell and influence activities of other cells; growth factors are proteins that bind to cell receptors and initiate cellular proliferation and differentiation
arachidonic acid
contained in walls of cells and released when cell is injured; degradation of arachidonic acid into derivatives of prostaglandins and thromboxanes causes a number of responses assoc w inflammatory response, including vasodilation, swelling, and pain
when do the phases of wound healing begin
only when the wound is covered by epithelium
other names for substrate phase
inflammatory phase, lag phase, or exudative phase
main cells involved in substrate phase
polymorphonuclear leukocytes (PMNs), platelets, and macrophages
how long do PMNs remain the predominant cell during substrate phase
48hr
what is a crucial part of normal wound healing
macrophages
when do monocytes reach max numbers during substrate phase
enter wound after PMN and reach max # 24hrs later
main cell involved in wound debridement
macrophages (what monocytes become)
tissue matrix metalloproteinases (TMMPs)
after injury stimulated and help degrade surrounding matrix proteins such as collagen and necrotic cellular macromolecules
interleukin 1 (IL 1)
important growth factor in regulation of many processes in the inflammatory response; induce fever, promote hemostasis by interacting with endothelial cells, enhance fibroblast proliferation, and active T cells
during primary wound healing, when does the substrate phase occur
occurs over approx 4day period
what does the wound like look like during substrate phase
edematous and erythematous
substrate phase during secondary or tertiary intention
continues indefinitely until wound surface is closed by ectodermal elements
characterized by the production of collagen in the wound
proliferative phase
appearance of the wound during proliferative phase
less edematous and inflamed; wound scar may be raised, red, and hard
primary cell of proliferative phase
fibroblast which produces collagen