Module 4 Inflammation & Repair Flashcards
Inflammation Purpose
- Destroy/limit spread of injurious agent
- Repair/replace damaged tissue
Inflammation Response Components
- Blood vessels
- Leukocytes (WBC)
R’s of Response
- Recognition
- Recruitment
- Removal
- Regulation
- Resolution
Recognition
- Offending agent identified
- By host cells & molecules
Recruitment
- Leukocytes & plasma proteins
- From circulation
Removal
- Agent destroyed & elimination
- By activated leukocytes & proteins
Regulation
- Reaction controlled & terminated
Resolution
- Repair damaged tissue
Response Coordination
- Macrophages recognize microbes & damaged cells
- Liberate mediators
- Trigger vascular & cellular reactions
Inflammation Principles
- Dynamic process
- Protective response (can be harmful)
- Non-specific reaction
- Modified by host & injurious/etiologic factors
- Injury in non-lethal
Blood Vessels in Response
- Dilations & opening of capillary beds
- Increased permeability
- Blood vessel lining alteration (endothelial)
- Endothelial cell contraction
Increased Permeability
- Protein rich fluid flows out into tissue
Endothelial Cell Contraction
- Response to histamine
- Leukocytes pass through
- Interendothelial spaces
Leukocytes
- Able to ingest microbes, dead cells, foreign material
Vascular Events
- Take place in arteries, capillaries, venules
Cellular Events
- WBCs/leukocytes
Chemical Events
- Release mediators
- Cause changes in cells & vessels
Vascular Reactions of Acute Inflammation
- Changes to blood flow
- Permeability of vessels
Purpose of Vascular Reactions
- Maximize leukocytes plasma protein movement
- Out of circulation to injury site
Vascular Events of Capillary Bed
- Transient vasoconstriction of arterioles
- Vasodilation of vessels (chemically mediated)
- Increase vascular permeability
Vasodilation of Vessels
- Opening of precapillary sphincters of arterioles
- Opening of new capillary beds
- Opening of arterial venous shunts
- Increase blood flow to affected area
- Visible redness (rubor)
- Heat (calor)
Increased Vascular Permeability
- Outpouring of fluids & proteins from vessels
- Escape of plasma/plasma proteins & WBC from vessel
- Edema & tissue swelling
Inducing Increased Vascular Permeability
- Histamine
- Kinins
- Produce gaps in endothelial cells
- Increase fluid passage through endothelium
Local Hemoconcentration
- Increased blood viscosity
- Packing of RBC
- Slowing blood flow
Cellular Events of Leukocytes
- Engulf, degrade bacteria, immune complexes, cell debris
- Release lysosomal enzymes
- Release chemical mediators
- Release toxic radicals
Margination
- Viscous blood from stagnation of blood flow
- WBCs pushed into periphery of vessels
Adhesion of Leukocytes
- To endothelium at inflammation site
- Promoted by cell adhesion molecules
Transmigration/Diapedesis
- Leukocytes through vessel wall
- Squeeze between widened endothelial cell gaps
- Penetrate basement membrane
Movement Towards Offending Agent
- Neutrophils (PMNs) attract to area of injury
- 1st type of leukocyte at inflamed area
- Later replaced by macrophages
Chemotaxis
- Attraction of cells (WBC) to site of injury
- By release factors from injured cells
- Movement along chemical gradient
Phagocytosis
- Inflammatory cells phagocytose invading agent/organism
- Process of ingestion of foreign components
- By neutrophils & macrophages
Phagocytosis Actions
- Recognition & attachment to neutrophil/macrophage
- Engulfment of micro-organisms by phagocytic cells
- Killing/degradation
Chemical Mediator Characteristics
- Produced locally or circulating
- Few targets or widespread activity
- Tightly regulated function
- Potential harmful effects
Cell-Derived Vasoactive Mediators
- Produced locally by cells
- At injury site
Plasma Derived Vasoactive Mediators
- Circulating within plasma
Histamine
- Cell-derived mediator
- Early phases of acute inflammation
- Released from mast cells
Histamine Functions
- Vasodilation of arterioles
- Increased vascular permeability in venules
Prostaglandins & Leukotrienes
- Cell-derived mediator
- Increase vascular permeability
Platelet Activating Factor Functions
- Vasodilation
- Increase vascular permeability
- Produces aggregation of platelets at injury site
Plasma Protease Systems
- 3 interrelated systems
- Series of inactive enzymes (proenzymes)
- Activation of first proenzyme
- Initiates cascade of enzyme activation
Kinin System
- Release bradykinin
Kinin System Functions
- Increase vascular permeability
- Contraction of smooth muscle
- Vasodilation
- Produces pain
Complement System
- Non-specific self defense mechanism