wound healing Flashcards
What are the 5 wound healing models?
- Superficial wound healing: only affects epidermis
- Primary intention-surgical;
- Delayed primary intention-surgical;
- Partial-thickness wound healing: epidermis destroyed, wound into dermis
- Full-thickness wound healing
What do Rete Pegs do?
Prevent shearing of dermis
The Simplified phases of healing
- inflammatory: platlets, fibrin, neutrophils, macrophages, mast cells
- Proliferative: fibroblasts, myofibroblasts, endothelial cells, keratinocytes
- Remodeling: collagen
What are platlets, neutrophils, & monocytes
- Platlets: small fragments in blood involved in homeostasis
- Neutrophils: phagocytic, clean up debris/bacteria
- Monocytes: WBC in response to inflammation will differentiate into macrophage
What are Endothelial cells, fibroblasts, myofibroblasts?
- EC: form endothelium, lining of blood vessels
- Fibro: produce protein fibers (collagen) and ECM
- Myofib: cell differentiated from fibroblast, contains actin/myosin system.
What are keratinocytes, mast cells?
- Ker: main cell in epidermis
- Mast cells- specialized secretory cell that helps promote fibroblast proliferation
What are Cytokines?
- Signaling molecules (peptides, proteins; essential for cell communication
- Play role during inflammation: attract immune cells for defense
Growth Factors?
- Proteins that are able to effect cell reproduction, movement, and function
- Can act on distant cells (endocrine stimulation), adjacent cells (paracrine stim), or on themselves (autocrine)
- Released in response to homeostatic control signals
What are Chemokines?
- Regulate trafficking of leukocyte population during normal health/development
- Direct activation of neutrophils, lymphocytes, macrophages, during inflammation.
What are MMP’s?
- Matrix metalloproteinases
- Family of 20 proteolytic enzymes; critical in achieving tissue degradation
- Require Ca ions for structural conformation; Zinic to function
What are TIMPS?
- Tissue inhibitors of metalloproteinase
- Synthesized by same cells that produce MMPs
What are some initial characteristics of the inflammatory phase?
- Begins at time of injury; lasts 3-7 days
- Clotting takes place hemostasis; factors released to rid debris, bacteria, damaged tissue
- Redness, warmth, pain, edema, dec ROM
What are the first initial steps in the inflammatory phase?
- Clotting & vasoconstriction to reduce BF
- Break down pre-existing tissue scaffolding; clean up debris
- Epidermal barrier disrupted; platelets are activated by collagen exposed by the injury (trigger vasoconstriction)
What is Hemostasis?
- Clot is formed made of cytokines, GF’s, fibrin, fibronectin, thrombosponinds (clotting cascade)
- Serves as scaffolding for migration of leukocytes, keratinocytes, fibroblasts, and endothelial cells (foundation for collagen deposition)
- Reservoir of GF’s
What do platelets secrete during the inflammatory phase?
- Multiple cytokines and GF’s: EGF, PDGF, TGF-B, IL-1
- Attract neutrophils to wound
- Monocyotes are transformed into macrophages
Describe wound space hypoxia during inflammatory phase?
- Vasoconstriction= dec O2; hypoxia controls wound healing
- Neutrophils, macrophages; stimulates endothelial cells- angiogenesis
- Shift to anaerobic glycolysis= inc lactate; wound becomes hyperlactic
The role of Neutophils during inflammatory phase
-Cleanse the wound; there w/in 24 hours; like hypoxic environment; part of pus
The role of Macrophage during inflammatory phase?
- Initiate angiogenesis & granulation tissue formation during proliferation
- Phagocytosis of debris (excrete lactic acid)
- Secrete collagenases- help break down damaged collagen that is there, being to lay new collagen
- Produce NO, secrete GF’s
