Applied Pathophysiology Lecture Notes PDF

Lecture Material is adapted from © 2022 Wolters Kluwer Health, Lippincott Williams & Wilkins Applied Pathophysiology: A Conceptual Approach to the Mechanisms of Disease Chapter 3: Inflammation and Tissue Repair Module 2: Healing and Tissue Repair Module 3: Chronic Inflammation Dr. Romeo Batacan J...

Lecture Material is adapted from © 2022 Wolters Kluwer Health, Lippincott Williams & Wilkins Applied Pathophysiology: A Conceptual Approach to the Mechanisms of Disease Chapter 3: Inflammation and Tissue Repair Module 2: Healing and Tissue Repair Module 3: Chronic Inflammation Dr. Romeo Batacan Jr. MPAT12001 Medical Pathophysiology Lecture Series Copyright © 2017 Wolters Kluwer Health | Lippincott Williams &Wilkins Healing and Tissue Repair Inflammatory response: sets the stage for healing and repair Goal of tissue healing and repair: Cover the wound Clear debris Restore structural integrity Restore functional integrity 3 phases 1. Inflammatory phase 2. Proliferative phase 3. Remodeling phase ECM: extracellular matrix PMN: polymorphonuclear neutrophils Covering the wound and clearing thedebris At the time of injury: hemostasis is triggered Vasoconstriction and clot formation Protective scab formation (thrombus): dried blood and exudate Physical barrier to prevent further harmful substances to enter Prevents the loss of plasma Epithelial cells regenerate under the thrombus Re‐epithelialization completed: enzymes degrade the scab Neutrophils move into injured area first Macrophages follow Digest, remove harmful substances/debris Necrotic cells and tissue must be removed before healing can start Restoring structural integrity Balance between destruction and construction Destruction: tissue lysis by enzymes Construction: growth factors and matrix proteins Extracellular matrix (ECM) is required 1. Basement membrane 2. Connective tissue layers Nowak T, Handford AG. Pathophysiology: Concepts and Applications for Health Care Professionals. 3rd ed.New York, McGraw‐Hill; 2004 Restoring structural integrity Damaged basement membrane and connective tissue layers must be replaced to support structure and tissue function Temporary extracellular matrix (provisional matrix) is formed after injury: proteins from plasma Decrease blood and fluid loss Attract and support fibroblasts, endothelial and epithelial cells Granulation tissue: provisional matrix is converted by macrophages Macrophages, fibroblasts Angiogenesis (re‐vascularization), new blood vessels Extensive network of capillaries Provisional matrix and granulation tissue reabsorbed once wound is healed Restoring structural integrity A: crush injury B: granulation tissue C: wound is closed with skin graft Kumar, Robbins & Cotran: Pathologic basis of disease. 8th ed. Philadelphia: Saunders;2010 Restoring functional integrity Major goal of healing: restore functional integrity of parenchymal tissue (tissue with specific function) If functional integrity not restored: functional loss There are 3 processes 1. Resolution 2. Regeneration 3. Replacement  Restoring functional integrity Labile: constantly regenerate Stable: stop regenerating, but can resume regeneration Permanent: do not regenerate Tissue class % Cells in Examples Mitosis Labile >1.5% Epithelial cells (skin, gastrointestinal, urinary), blood cells in red bone marrow Stable