Module 2 - Acute And Chronic Inflammation Flashcards
What are the four signs of inflammation?
Redness, swelling, heat and pain
Rubor, tumor, calor and dolor
What are the three characteristics of inflammation?
Vasodilation
Increases vessel permeability
Diapedesis
What is the role of vasodilation in inflammation?
Blood vessels dilate to slow blood flow and increase blood volume to injured site
What is the role of increased vascular permeability in inflammation?
Retraction of endothelial cells causes gaps to open between cells, allowing leakage of plasma (increased blood volume)
What is the role of Diapedesis in inflammation?
White cells adhere to inner wall of capillaries and migrate through junctions in endothelial cells to surrounding tissue
What are the benefits of inflammation?
Limits/controls tissue damage
Prevents infection by contaminating organisms
Initiates adaptive immune response
Initiates healing through removal of bacterial products
What cells are involved in chronic inflammation?
Lymphocytes and macrophages
What is a granuloma?
Forms when macrophages cannot protect from tissue damage
What is the role of mast cells?
Releases inflammatory mediators
Where are mast cells located?
Loose connective tissue, lining of gastrointestinal and respiratory tract
What is the role of basophils?
Releases cytokines, leukotrienes and histamine to aid immunity
What is the role of neutrophils?
Travels to site of infection and destroys microorganism by ingestion
What is the role of monocytes?
Migrates to inflammatory site and differentiates into macrophages
What is the role of macrophages?
Secretes pro-inflammatory/antimicrobial mediators
What is the role of eosinophils?
Primary defence against parasites and regulates vascular mediators
What is the role of platelets?
Activates after injury, results in interaction with components of coagulation cascade to stop bleeding
What is the causative agent of acute inflammation?
Pathogens, irritants or damage
What is the causative agent of chronic inflammation?
Persistent, acute inflammation, persistent forgien bodies or autoimmune reaction
What are chemical mediators?
Substances that promote inflammation
What is the role of histamines?
Causes rapid contraction of smooth muscle and dilation of capillary venules (increased blood flow)
What is the role of chemotactic factors?
Diffuses from site of inflammation and form gradient to cause directional movement towards injury
What is the role of neutrophil chemotactic factor?
Kills bacteria
What is the role of eosinophil chemotactic factor?
Regulates inflammatory response
What is the role of leukotrienes?
Produces histamine like effect
What is the role of nitric oxide?
Causes vasodilation by inducing relaxation of smooth muscle, suppress mast cell release and decrease platelet adhesion
What is the role of prostaglandins?
Causes increased vascular permeability, neutrophil chemotaxis and pain
What is the role of platelet activating factor?
Endothelial cell retraction to increase vascular permeability and platelet adhesion
What is the role of cytokines?
Binds to target cells and affects function
What is the role of the complement system?
Destroys pathogens directly
What is the coagulation system and what is its role?
Group of plasma proteins that form fibrinous network at injured site to stop bleeding
What are the three activation pathways of the complement system?
Classical
Alternative
Lectin
How is the classical pathway activated?
Antibodies
What is the alternative pathway activated?
Gram-negative bacterial/fungal cell wall polysaccharides
What activated the lectin pathway?
Bacterial carbohydrates
What is the role of the kinin system?
Produces bradykinin causing vasodilation, smooth muscle contraction and increased vascular permeability
Describe the pathogenesis of fever
Tissue injury stimulates immune cells (macrophages, T-cells) to release cytokines, stimulating the hypothalamus to cause increased muscle tone, increased shivering, vasoconstriction and piloerection
What are the benefits of fever?
Kills/inhibits growth of microorganisms
Decreases iron, zinc and copper blood levels
Prevents viral replication through lysosomal breakdown and cell auto destruction
What is degranulation?
Granules from mast cells are released extracellularly
What are the two ways a wound heals by?
Primary intention and secondary intention
What are the two phases involves in wound healing?
Reconstruction phase and maturation phase
What is primary intention?
Wounds heal under minimal tissue loss
What is secondary intention?
Healing of an open wound requiring tissue replacement
What is involves in the reconstruction phase?
Bleeding is sealed by clot, granulation tissue grows into wound and wound contraction occurs
What is involved in the maturation phase?
Scar tissue is remodelled and capillaries disappear, leaving scar avascular
What are the causes of dysfunctional wound healing?
Predisposing factors such as diabetes mellitus or acquired condition such as hypoxaemia
