Podcast
Questions and Answers
What constitutes the first line of defense in innate immunity?
What constitutes the first line of defense in innate immunity?
Which bio-chemical barrier is NOT part of innate immunity?
Which bio-chemical barrier is NOT part of innate immunity?
What is the role of T helper cells in adaptive immunity?
What is the role of T helper cells in adaptive immunity?
Which of the following best describes the process of white blood cell (WBC) extravasation?
Which of the following best describes the process of white blood cell (WBC) extravasation?
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What type of cells are responsible for presenting antigens to T cells?
What type of cells are responsible for presenting antigens to T cells?
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Which physiological change occurs during the inflammatory response?
Which physiological change occurs during the inflammatory response?
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What defines a host in the context of infections?
What defines a host in the context of infections?
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What is the significance of the complement system in innate immunity?
What is the significance of the complement system in innate immunity?
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Study Notes
Host Defense Mechanisms
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Innate Immunity: The body's first line of defense against pathogens.
- First Line of Defense: Physical and mechanical barriers (skin, linings of GI/GU/Respiratory tracts; sloughing, mucus/cilia, coughing/sneezing) and biochemical barriers (sweat, saliva, tears, sebum, normal flora, antimicrobial peptides like defensins and collectins, complement system).
- Second Line of Defense: Inflammatory response triggered by infection, damage, etc. Characterized by local manifestations (redness, heat, swelling, pain, loss of function) and a vascular response (dilation, increased permeability, white blood cell extravasation—rolling, firm adhesion, transmigration).
- Cells of Innate Immunity:
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Neutrophils: Phagocytic cells; recognize and engulf bacteria.
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Monocytes/Macrophages: Phagocytic cells.
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Dendritic cells: Antigen-presenting cells.
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Natural Killer (NK) cells: Recognize altered host molecules.
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Adaptive Immunity: The body's specific response to pathogens.
- T cells: Crucial in adaptive immunity.
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T helper cells (CD4+): Orchestrate the adaptive immune response by activating other immune cells and differentiating between pathogens.
Infection, Colonization, and Virulence
- Host: An organism supporting the growth of another.
- Colonization: Establishing presence of an organism.
- Infection: Presence and multiplication of an organism within a host, causing injury.
- Virulence: Disease-producing potential of an organism.
Hypersensitivity Disorders
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Hypersensitivity: Inappropriate immune system activation.
- Type I (Allergic): IgE-mediated response, tissue damage (e.g., asthma).
- Type II: IgG or IgM mediated.
- Subtype 1: Complement and antibody-mediated, e.g., mismatched blood transfusion.
- Subtype 2: Complement and antibody inflammation, affecting extracellular tissue (e.g., lungs, kidneys).
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Subtype 3: Antibody-mediated cellular dysfunction (e.g., Graves disease, Myasthenia gravis).
- Type III: Massive antigen-antibody complexes, tissue damage/necrosis (e.g., Systemic lupus erythematosus, Serum sickness).
- Type IV (Cell-Mediated): Direct cell cytotoxicity, e.g., Hepatitis B, tuberculin test.
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Description
Explore the essential components of the body's immune system, focusing on innate immunity's first and second lines of defense. This quiz covers the roles of various immune cells and the body's biochemical barriers against pathogens. Gain a deeper understanding of how the immune system safeguards health.
