Inflammation Study Quiz

Inflammation

• Inflammation is a protective immune-vascular response that is a reaction of living tissue against injury.
• Causes of inflammation include infectious agents, immunological responses, tissue necrosis, chemical and physical agents, and nutritional factors.
• Components of inflammation include the cause, immune cells, blood vessels, and chemical mediators.
• The purpose of inflammation is to eliminate the cause, clear necrotic cells, and initiate repair.

Cardinal Signs of Inflammation

• Redness: caused by vasodilatation
• Swelling: caused by inflammatory fluid exudate (edema fluid)
• Pain: caused by irritation of nerve endings by toxins and chemical mediators or compression by the exudate
• Loss of function
• Fever: caused by the release of chemical mediators
• Leukocytosis: an increase in the number of white blood cells (WBCs)

Leukocyte Extravasation

• Chemo-attraction: recognition of pathogens by leukocytes, resulting in the release of IL-1, TNF-α, and endothelial cells expressing E and P selectins
• Rolling: carbohydrate ligands on leukocyte surfaces bind to selectins, causing rolling
• Adhesion: activation of integrin molecules on the surface of rolling leukocytes, leading to tight binding to receptors in endothelial cells and immobilization of leukocytes
• Transmigration: leukocytes pass through gaps between intact endothelial cells, facilitated by pseudopodia and proteolytic digestion of the basement membrane

Neutrophils

• Function: phagocytosis and killing of microorganisms using ROS and lysosomes
• Dilution of toxins
• Fibrinogen forms a network of fibrin threads, causing localization of infection and facilitating the movement of leukocytes

Antibody Functions

• Neutralization: blocking of antigen receptors
• Opsonization: coating of microorganisms to facilitate phagocytosis
• Agglutination: clumping of microorganisms to prevent spread
• Antibody-mediated cell cytotoxicity: activation of NK cells
• Activation of complement: phagocytosis, cell lysis, and inflammation

Complement

• A part of the immune system consisting of a number of small proteins formed in the liver and circulating in an inactive form
• Functions: cell lysis, inflammation, and opsonization
• Mechanism: stimulated by antigen-antibody or bacteria, works by cleavage of specific protein parts, release of cytokines, and activation of the cell-killing membrane attack complex

Phagocytosis

• Engulfing of foreign bodies, such as bacteria and debris, by neutrophils and macrophages
• Functions: cleaning and clearing the area of inflammation for repair
• Factors that help phagocytosis: opsonins, complement, fibrin, and mild fever
• Steps of phagocytosis: chemotaxis, adherence of microbe to phagocytes, ingestion, phagosome formation, fusion of phagosome with a lysosome, digestion by enzymes, and discharge of waste materials

Acute and Chronic Inflammation

• Acute inflammation: rapid onset, short duration (few days), toxemia present, and microscopically characterized by neutrophils and macrophages, with numerous, thin-walled, dilated, and blood-filled vessels
• Chronic inflammation: gradual onset, long duration (months or years), toxemia absent, and microscopically characterized by macrophages, lymphocytes, plasma cells, giant cells, and fibroblasts, with less numerous, thick-walled vessels showing angiogenesis or endarteritis obliterans