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Questions and Answers
What is the primary role of the skin in the immune system?
What is the primary role of the skin in the immune system?
Which of the following is NOT part of the nonspecific immune mechanisms?
Which of the following is NOT part of the nonspecific immune mechanisms?
How does the mucous membrane contribute to the immune defense?
How does the mucous membrane contribute to the immune defense?
What is one function of gingival crevicular fluid in the immune system?
What is one function of gingival crevicular fluid in the immune system?
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Which of the following components helps in destroying microbes entering the respiratory system?
Which of the following components helps in destroying microbes entering the respiratory system?
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What role does keratinization play in the gingival epithelium?
What role does keratinization play in the gingival epithelium?
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Which substance is continuously secreted by host cells to counter potential infections?
Which substance is continuously secreted by host cells to counter potential infections?
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What is one of the main interacting mechanisms of the second line of defense in the immune system?
What is one of the main interacting mechanisms of the second line of defense in the immune system?
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What percentage of white blood cells do monocytes constitute?
What percentage of white blood cells do monocytes constitute?
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What are macrophages primarily known for?
What are macrophages primarily known for?
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Where are fixed macrophages primarily found?
Where are fixed macrophages primarily found?
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What type of immunity is primarily based on the circulation of antibodies?
What type of immunity is primarily based on the circulation of antibodies?
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What role do neutrophils play in inflammation?
What role do neutrophils play in inflammation?
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What is indicated by the development of edema and erythema?
What is indicated by the development of edema and erythema?
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What substances do anaphylatoxins C3a and C5a stimulate?
What substances do anaphylatoxins C3a and C5a stimulate?
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Chronic inflammatory cells primarily protect the host by:
Chronic inflammatory cells primarily protect the host by:
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What role do interferons play in the immune response?
What role do interferons play in the immune response?
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Which of the following statements about complement proteins is true?
Which of the following statements about complement proteins is true?
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What triggers a local inflammatory response?
What triggers a local inflammatory response?
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What is the main purpose of self-tolerance in the immune system?
What is the main purpose of self-tolerance in the immune system?
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Which type of Major Histocompatibility Complex (MHC) is found on all nucleated cells?
Which type of Major Histocompatibility Complex (MHC) is found on all nucleated cells?
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What characteristic describes neutrophils in the context of their function?
What characteristic describes neutrophils in the context of their function?
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What is the life span of neutrophils as they destroy foreign invaders?
What is the life span of neutrophils as they destroy foreign invaders?
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In what way do phagocytes function in the immune system?
In what way do phagocytes function in the immune system?
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What is the primary role of neutrophils in controlling bacterial infections?
What is the primary role of neutrophils in controlling bacterial infections?
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Which cytokine is expressed by the junctional epithelium to create a chemotactic gradient for neutrophils?
Which cytokine is expressed by the junctional epithelium to create a chemotactic gradient for neutrophils?
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What is the consequence of disorders affecting neutrophil chemotaxis?
What is the consequence of disorders affecting neutrophil chemotaxis?
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Which of the following is a function of neutrophils?
Which of the following is a function of neutrophils?
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What process involves the coating of bacteria with host proteins to facilitate phagocytosis?
What process involves the coating of bacteria with host proteins to facilitate phagocytosis?
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Which virulence factor does P.gingivalis produce that affects neutrophil function?
Which virulence factor does P.gingivalis produce that affects neutrophil function?
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How do neutrophils recognize opsonized bacteria?
How do neutrophils recognize opsonized bacteria?
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What is the primary response of the immune system upon contact with bacterial lipopolysaccharides (LPS)?
What is the primary response of the immune system upon contact with bacterial lipopolysaccharides (LPS)?
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What role do antigen-presenting cells (APCs) play in the immune response within gingival tissues?
What role do antigen-presenting cells (APCs) play in the immune response within gingival tissues?
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How does scaling and root planing contribute to the immune defense against periodontal pathogens?
How does scaling and root planing contribute to the immune defense against periodontal pathogens?
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What is the significance of antibodies specific for P.gingivalis in periodontitis patients?
What is the significance of antibodies specific for P.gingivalis in periodontitis patients?
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What mechanism is impaired in the periodontal pocket compared to a healthy gingival sulcus?
What mechanism is impaired in the periodontal pocket compared to a healthy gingival sulcus?
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What is the primary consequence of diminished oxidative killing in periodontal disease progression?
What is the primary consequence of diminished oxidative killing in periodontal disease progression?
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What do nonoxidative mechanisms of killing involve in neutrophils?
What do nonoxidative mechanisms of killing involve in neutrophils?
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How does the leukotoxin of A.a. affect phagocytes during an immune response?
How does the leukotoxin of A.a. affect phagocytes during an immune response?
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What defines the clinical manifestation of disorders like cyclic neutropenia?
What defines the clinical manifestation of disorders like cyclic neutropenia?
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Study Notes
Nonspecific Defense Mechanisms
- Skin is a physical barrier that's normally impervious to bacteria and viruses, cuts or abrasions can allow pathogens to enter.
- Mucous Membranes line body cavities and passages, secrete mucus that traps pathogens.
-
Saliva contains several antimicrobial substances:
- Salivary Peroxidase System
- Hydrogen Peroxide
- Lactoferrin
- Lysozyme
-
Gingival Crevicular Fluid
- Bathes the gingival sulcus, washing away bacteria and their products.
- Contains inflammatory mediators, protease inhibitors, and host defense agents.
Immune Cells
- Interferons are proteins secreted by virus-infected cells that inhibit neighboring cells from making new viruses.
- Complement Proteins are involved in both nonspecific and specific defense, initiating inflammation, opsonization, and cell lysis.
Inflammation
- Triggered by tissue damage, injured cells release histamine, dilating blood vessels and increasing capillary permeability.
- This allows phagocytic white blood cells to enter the interstitial fluid.
Self-Tolerance
- Lymphocytes bearing antigen receptors mature in the thymus and bone marrow.
- Lymphocytes with receptors for self molecules are destroyed or inactivated.
Major Histocompatibility Complex (MHC)
- Biochemical fingerprint unique to each individual.
- Class I MHC is found on all nucleated cells.
-
Class II MHC is found on specialized cells of
the immune system.
Phagocytosis
- Ingestion of invading particles by certain white blood cells.
- Neutrophils: 60-70% of white blood cells, attracted by chemical signals, destroy microbes and often self-destruct in the process.
- Monocytes mature into macrophages.
Macrophages
- Largest phagocytic cells, move through tissues and engulf cellular debris and pathogens.
- Stimulate lymphocytes and other immune cells to respond to pathogens.
- Located at strategic points where microbial invasion is likely (e.g., lymph nodes, spleen).
Humoral and Cell-Mediated Immunity
- Humoral immunity relies on antibodies circulating in the blood and lymph, defending against extracellular threats.
- Cell-mediated immunity targets transplanted tissue and cancer cells.
Inflammation in Response to Bacterial Infection
- Innate factors, including complement, leukocytes, and mast cells, initiate inflammation by signaling endothelium.
- Neutrophils control bacteria within the gingival crevice and epithelium.
- Macrophages and lymphocytes protect the host within the connective tissues, preventing systemic infection.
Role of Neutrophils in Controlling Bacterial Invasion
- Neutrophils are the first leukocytes to arrive at the site of inflammation and are the dominant cell type within the junctional epithelium and gingival crevice.
- Neutrophil functions, including chemotaxis, transepithelial migration, opsonization, phagocytosis, and intracellular killing, must be intact to effectively control bacterial infections.
- Disorders of neutrophils are linked to invasive periodontal infection and aggressive periodontitis.
- Neutrophil transepithelial migration depends on a chemotaxin gradient.
- P. gingivalis can prevent transepithelial migration and inhibit IL-8 secretion.
Opsonization and Phagocytosis
- Opsonization: coating bacteria with host proteins to facilitate phagocytosis.
- IgG isotype facilitates direct phagocytosis by binding to the neutrophil Fc receptor.
- Antigen-presenting cells (APCs) transport antigen to lymph nodes, promoting IgG antibody production.
- Scaling and root planing stimulates antibody production against microorganisms like P. gingivalis and A.a.
Role of Antibodies in Periodontal Health
- Antibodies facilitate clearance of periodontal pathogens, promoting opsonization and phagocytosis.
- Neutralize bacterial components involved in colonization and host cell interactions.
- Antibodies specific to P. gingivalis prevent recolonization of deep periodontal pockets.
Immune System and Periodontal Disease
- Periodontal pathogens can evade phagocytic cells as a virulence mechanism (e.g., leukotoxin of A.a.).
- Specific antibodies to A.a. or antileukotoxin serum protect neutrophils from leukotoxin-mediated injury, enabling phagocytosis.
- Periodontal manifestations of neutrophil disorders
can include:
- Cyclic neutropenia: reduction in circulating neutrophils.
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Description
Test your knowledge on the nonspecific defense mechanisms of the immune system, focusing on physical barriers like skin and mucous membranes, as well as the role of immune cells. This quiz also covers inflammatory responses and the functions of various proteins involved in immunity.
