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38 Cards in this Set
- Front
- Back
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Which cells migrate to the site of injury?
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WBCs (leukocytes), NOT RBCs (erythrocytes)
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What is the primary role of erythrocytes in regards to healing?
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Carrying O2 on hemoglobin, O2 is required for healing (ischemia will delay healing)
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What is the difference between a monocyte and a macrophage?
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Monocyte - circulating throughout the body
Macrophage - once it reaches site of injury |
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What do monocytes/macrophages do?
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Phagocytosis, primarily chronic inflammation
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What stage are lymphocytes mainly present?
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Chronic inflammation
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When are eosinophils found?
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Allergic reactions
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What are the first responders to acute inflammation?
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Neutrophils
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What do neutrophils do?
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Phagocytosis - first responders to acute inflammation
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Why are basophils important?
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They contain histamine (vasodilator), but are NOT phagocytic
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Where are mast cells found and what do they do?
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Found in CT, release substances (histamine, heparin) in response to tissue injury and inflammation
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What is the role of platelets?
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Promote blood clotting, are also the first "cells" at the injury site
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Where are fibroblasts found and what do they do?
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Found in connective tissue, form collagen fibers to give rise to new CT
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What are the three phases of healing and how long does each last?
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Inflammation (1ish week)
Proliferation (3 days-3 weeks) Maturation (9 days-two years - pink scar) |
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What are the five primary signs of tissue inflammation?
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Heat, pain, swelling, redness, loss of function
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How does the vascular system first respond to tissue injury?
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Vasoconstriction of injured vessels during the first 5-10 minutes, mediated by norepinepherine to control bleeding until platelets are brought in
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What step occurs in the inflammatory process following vasoconstriction?
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Vasodilation and increased permeability to increase permeability to bring leukocytes to the injured area - mediated by histamine, Hageman factor, bradykinin, prostaglandins
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What is extravasation?
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The process of a leukocyte migrating from the vessel to the tissue
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What is the primary role of histamine during inflammation and whas is it released from?
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Vasodilation, increased permeability (thus, edema)
Released from mast cells, platelets, basophils |
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What does bradykinin do?
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Mediates the inflammatory process, increases vasodilation and causes contraction of smooth muscle
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What is the role of prostaglandins in inflammation?
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Attracts leukocytes via chemotaxis, sensitizes pain receptors
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What substances help form a clot?
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Platelets, fibrin, collagen
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What are the main goals of PT during the inflammatory process?
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Protect the area (collagen matrix is still week for first week-ish), prevent inflammation from getting out of hand (use modalities to decrease inflammation, especially edema, and try to move to proliferation stage)
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Waht are the four stages of proliferation?
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epithelialization, collagen production, wound contraction, neovascularization, angiogenesis
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What is epithelialization?
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Reestablishing the epidermis is the skin is damaged; healthy cells from the margins of the injury reproduce and migrate to cover the wound
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What cells create collagen?
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Fibroblasts
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What is the difference between Type III and Type I collagen?
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Type III is produced first, and it is a thin, weak-structured collagen, spaghetti-like with little organization
Type I is produced later, more rope-like and much stronger |
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What cells are primarily responsible for wound contraction and what do they do?
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Myofibroblasts - like fibroblasts, but with contractile properties; bring edges of wound together to result in a smaller scar
Want CONTROLLED motion (uncontrolled motion may cause a contracture = bad!) |
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Why is a scar red early in the proliferation phase?
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Because there is an increase in vascularity and fluid, increased innervation and the tissue is relatively immature
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What is a contracture and how is it treated?
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Uncontrolled wound contraction, very resistant to passive stretch; very fibrous and may need surgery to release
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What is neovascularization or angiogenesis and why does it occur?
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Development of new blood supply to the area, since oxygen and nutrients are required for healing
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Why is immobilization sometimes good during neovascularization/angiogenesis?
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Protect small blood vessels and promote growth; excessive motion may cause microhemorrhage and increase likelihood of infection
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What occurs during maturation?
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Collagen deposited and reabsorbed (more type I, not III), tissue changes in shape/structure for optimal recovery
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Why does a scar become whiter during the maturation or remodeling phase?
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Collagen matures, vascularity decreases
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The two theories regarding scar formation are Induction and Tension. What's the difference?
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Induction - scars mimic the characteristics of the tissue it's healing
Tension - Internal and external stresses placed on injured area during maturation determine final structure (think Wolff's law) |
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What's the big problem with immobilization during healing?
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Reduces tensile strength and collagen structure for months after immobilization is removed
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When does chronic inflammation occur?
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Persistence of injurious agent or interference with normal healing process or immune response to foreign material (sutures, hardware) or autoimmune disease (RA)
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What are some local factors that affect tissue or wound healing?
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Type (surgical vs. traumatic), size (big vs. small), location (well- vs. poorly vascularized), wound dimension (linear fastest, circular slowest), infection, vascular supply, external forces (physical technologies, movement)
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What are some systemic factors that affect tissue or wound healing?
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Age, disease, medications (corticosteroids/NSAIDs), nutrition
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