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Questions and Answers
What is the primary function of thromboxane in the body?
What is the primary function of thromboxane in the body?
Arachidonic acid is metabolized by two pathways: cyclooxygenase (COX) and lipoxygenase. Which of the following is a product of the COX pathway?
Arachidonic acid is metabolized by two pathways: cyclooxygenase (COX) and lipoxygenase. Which of the following is a product of the COX pathway?
Which of the following is NOT a pro-inflammatory interleukin?
Which of the following is NOT a pro-inflammatory interleukin?
What is the primary effect of nitric oxide in the body?
What is the primary effect of nitric oxide in the body?
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What is the primary function of prostaglandins in the body?
What is the primary function of prostaglandins in the body?
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What is the primary function of the mucociliary blanket in the respiratory tract?
What is the primary function of the mucociliary blanket in the respiratory tract?
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Which of the following cells play a crucial role in the regulation of cellular changes during inflammation?
Which of the following cells play a crucial role in the regulation of cellular changes during inflammation?
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Which of the following is a characteristic of chronic inflammation?
Which of the following is a characteristic of chronic inflammation?
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What is the primary function of IgA secreted by mucous membranes in the gut?
What is the primary function of IgA secreted by mucous membranes in the gut?
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Which of the following is NOT a function of the inflammation response?
Which of the following is NOT a function of the inflammation response?
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What is the primary function of mast cells during inflammation?
What is the primary function of mast cells during inflammation?
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Which of the following is a characteristic of the inflammation response?
Which of the following is a characteristic of the inflammation response?
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What is the primary function of gastric acid in the gastrointestinal tract?
What is the primary function of gastric acid in the gastrointestinal tract?
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Which of the following is NOT a component of the innate immunity in the gastrointestinal tract?
Which of the following is NOT a component of the innate immunity in the gastrointestinal tract?
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What is the primary function of bradykinin in the inflammatory response?
What is the primary function of bradykinin in the inflammatory response?
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What is the main function of clotting factors in the inflammatory response?
What is the main function of clotting factors in the inflammatory response?
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What is the role of complement proteins in the inflammatory response?
What is the role of complement proteins in the inflammatory response?
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What is the role of arachidonic acid metabolites in the inflammatory response?
What is the role of arachidonic acid metabolites in the inflammatory response?
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Which of the following is NOT a function of complement proteins?
Which of the following is NOT a function of complement proteins?
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Which of the following chemical mediators of inflammation is responsible for bronchodilation?
Which of the following chemical mediators of inflammation is responsible for bronchodilation?
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Study Notes
Arachidonic Acid Metabolites
- Arachidonic acid is a fatty acid present in the cell membrane
- Metabolized by two pathways: Cyclooxygenase (COX) and Lipoxygenase
- COX pathway produces:
- Prostaglandins (promote bronchoconstriction and vasodilation)
- Thromboxane (promotes platelet aggregation)
- Aspirin/NSAIDs block COX pathway
- Lipoxygenase pathway produces:
- Leukotrienes (promote bronchoconstriction and increase capillary permeability)
Chemical Mediators of Inflammation
- Interleukins (IL) and Tumor Necrosis Factor (TNF):
- Proteins produced by lymphocytes and macrophages
- Many kinds, some pro-inflammatory (IL-1β, IL-6), some anti-inflammatory (IL-4, IL-10)
- Many overlapping functions, including:
- Recruitment and activation of leukocytes
- Induction of acute-phase responses
- Interferons:
- Produced by virus-infected cells and lymphocytes
- Enhance defense against viruses by inhibiting DNA/RNA synthesis
- Some activate macrophages to destroy viruses
- Nitric oxide:
- Produced by endothelial cells
- Promotes smooth muscle relaxation and vasodilation
Types of Inflammation
- Acute inflammation:
- Early, short-term, and self-limiting
- Occurs before adaptive immunity can exert its effect
- Designed to remove injurious agent and limit extent of damage
- Neutrophils predominate in first 24 hours
- Chronic inflammation:
- Late, long-term, and self-perpetuating
- Usually the result of recurrent inflammation/irritation or slow processes that fail to induce an acute response
- Macrophages and lymphocytes are more common
Acute Inflammation: Vascular Response
- Following tissue injury:
- Clear pathogens and debris from injured tissue/wounds
- Coordinate vascular and cellular aspects of inflammation
- Tightly regulated with lots of checks and balances
Chemical Mediators of Inflammation
- Histamine:
- First inflammatory mediator released
- Produced by mast cells
- Responsible for:
- Vasodilation
- Increased vascular permeability
- Bronchoconstriction
- Temporary, with leukotrienes taking over once synthesized
- Bradykinin:
- Initiated by activation of Hageman factor (factor XII)
- Responsible for:
- Vasodilation
- Increased vascular permeability
- Bronchoconstriction
- Pain
- Clotting factors:
- Produced by liver
- Induce the clotting cascade
- Lead to production of fibrin clot
- Complement proteins:
- Plasma proteins
- Present in inactive form
- As part of inflammation:
- Increase vascular permeability
- Promote chemotaxis
- As part of immune system:
- Act as opsonins and facilitate phagocytosis
- Create holes in cell membrane of pathogens (membrane attack complex - MAC)
Innate Immunity: The Gastrointestinal Tract
- Gastrointestinal tract:
- Most pathogens are transported via food contaminated with fecal material
- Gastric acid destroys pathogens in stomach
- Viscous mucous layer coats gut and entraps microbes
- Pancreatic enzymes and bile detergents destroy organisms
- IgA secreted by mucous membranes in gut
- Normal bacterial flora compete with pathogens for nutrients
Inflammation
- SECOND LINE OF DEFENSE
- Programmed response to tissue injury
- Integrated system of humoral and cellular responses designed to:
- Limit tissue damage
- Destroy pathogens
- Initiate adaptive immune system
- Begin healing
- Rapid response in vascularized tissue (begins in seconds)
Cells of Inflammation
- Endothelial cells:
- Layer of cells lining blood vessels
- Release nitric oxide (NO) to promote vasodilation
- Release inflammatory mediators (interleukins, prostaglandins, etc.) to regulate cellular changes during inflammation
- Control movement of cells through endothelial layer
- Release tissue factor in response to injury (activates extrinsic pathway of clotting cascade)
- Mast cells:
- Cells that lie in connective tissue near blood vessels
- When activated, mast cells:
- Degranulate (release inflammatory mediators stored in cellular granules)
- Immediate response, primarily histamine
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Description
This quiz covers the metabolism of arachidonic acid, a fatty acid found in cell membranes, and its two main pathways: cyclooxygenase (COX) and lipoxygenase, and their respective products, prostaglandins, thromboxane, and leukotrienes.
