Innate Immunity Overview
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What role does body temperature play in innate immunity?

  • It alters the pH of cellular environments.
  • It can inhibit the growth of certain pathogens. (correct)
  • It enhances the activity of T-cells.
  • It directly stimulates the production of antibodies.

    • How does gastric acidity function as a barrier to infection?

  • It induces fever to fight pathogens.
  • It enhances nutrient absorption in the intestines.
  • It kills most ingested microorganisms due to low pH. (correct)
  • It activates antimicrobial proteins in the gut.

    • What is the primary function of collectins in the immune response?

  • To phagocytose and digest microorganisms
  • To enhance the signaling of immune cells
  • To disrupt the cell wall of pathogens (correct)
  • To produce secretory proteins

    • What are pathogen-associated molecular patterns (PAMPs)?

    <p>Molecules that trigger innate immune responses.</p> Signup and view all the answers

    What role do antimicrobial proteins and peptides play in innate immunity?

    <p>They provide ongoing protection against pathogens.</p> Signup and view all the answers

    What type of receptors are essential for detecting pathogens in the innate immune system?

    <p>Pattern recognition receptors (PRRs)</p> Signup and view all the answers

    Why are newborns more susceptible to certain infections compared to adults?

    <p>Their stomach contents are less acidic.</p> Signup and view all the answers

    What is the role of phagocytic cells in the immune response?

    <p>To induce vascular leakage and promote inflammation</p> Signup and view all the answers

    How do epithelial barriers contribute to innate immunity?

    <p>By physically isolating the body's interior from pathogens</p> Signup and view all the answers

    What is the primary role of NOD1 and NOD2 in the immune system?

    <p>They contribute to the elimination of cytosolic bacteria via autophagy.</p> Signup and view all the answers

    What components are included in the external anatomical barriers of innate immunity?

    <p>Skin and mucous membranes</p> Signup and view all the answers

    Which statement accurately describes the NOD-like receptors (NLRs)?

    <p>They are activated by intracellular PAMPs and substances signifying danger.</p> Signup and view all the answers

    What is the primary function of keratin in the epidermis?

    <p>To waterproof and protect skin cells</p> Signup and view all the answers

    What is the significance of damage-associated molecular patterns (DAMPs)?

    <p>They signal tissue damage to immune cells.</p> Signup and view all the answers

    What consequence can result from certain NLRs triggering inflammation?

    <p>Extensive tissue damage and the development of disease.</p> Signup and view all the answers

    What are the specialized cells involved in the process of phagocytosis?

    <p>Blood monocytes and tissue macrophages</p> Signup and view all the answers

    What happens when there are breaks in the physical barriers of the body?

    <p>Pathogenic microbes can exploit these breaks if not properly defended.</p> Signup and view all the answers

    What key feature distinguishes the epidermis from the dermis?

    <p>The thickness and cellular composition</p> Signup and view all the answers

    Which of the following illustrates a cardinal sign of inflammation?

    <p>Swelling (tumor).</p> Signup and view all the answers

    What is primarily secreted by the body’s epithelial surfaces to combat pathogens?

    <p>Antimicrobial peptides and proteins</p> Signup and view all the answers

    What is the approximate number of NLR genes present in the human genome?

    <p>23</p> Signup and view all the answers

    How do molecular components of microbes, such as LPS, elicit an immune response?

    <p>Through interaction with cell surface receptors.</p> Signup and view all the answers

    According to Celsus, what are the 'four cardinal signs' of inflammation?

    <p>Redness, swelling, heat, and pain.</p> Signup and view all the answers

    What complex series of events is triggered by tissue damage caused by a wound or pathogen?

    <p>The inflammatory response.</p> Signup and view all the answers

    What physiological change results in tissue redness and increased temperature during the inflammatory response?

    <p>Vasodilation</p> Signup and view all the answers

    What is the primary purpose of increased capillary permeability during inflammation?

    <p>To allow fluid and cells to enter the tissue</p> Signup and view all the answers

    Which process describes the movement of phagocytes through the tissue toward the site of invasion?

    <p>Chemotaxis</p> Signup and view all the answers

    What role do acute-phase proteins play in the inflammatory response?

    <p>Increase dramatically in response to tissue damage</p> Signup and view all the answers

    Which cells are primarily responsible for the adherence and subsequent emigration during the inflammatory cascade?

    <p>Phagocytes</p> Signup and view all the answers

    How are chemical mediators involved in the inflammatory response?

    <p>They consist of a complex interplay of various sources.</p> Signup and view all the answers

    Which of the following best describes margination in the context of the inflammatory response?

    <p>The sticking of phagocytes to the endothelial cells</p> Signup and view all the answers

    Which acute-phase protein is notably produced by the liver in response to tissue damage?

    <p>C-reactive protein</p> Signup and view all the answers

    What role does C-reactive protein play in the immune response?

    <p>It activates the complement system to enhance pathogen clearance.</p> Signup and view all the answers

    What is the primary action of histamine in response to tissue injury?

    <p>Causes vasodilation and increases capillary permeability.</p> Signup and view all the answers

    How do kinins contribute to the inflammatory response?

    <p>They stimulate pain receptors and promote vasodilation.</p> Signup and view all the answers

    Which of the following best describes the function of fibrin in the inflammatory response?

    <p>It walls off the injured area to prevent the spread of infection.</p> Signup and view all the answers

    What is the main characteristic of phagocytosis compared to other forms of endocytosis?

    <p>It forms large vesicles called phagosomes.</p> Signup and view all the answers

    What initiates the tissue repair process after the inflammatory response?

    <p>The clearance of debris by phagocytic cells.</p> Signup and view all the answers

    Which type of endocytosis is primarily responsible for fluid uptake?

    <p>Pinocytosis.</p> Signup and view all the answers

    What is the protective function of pain during the inflammatory response?

    <p>It prompts individuals to avoid the injured area.</p> Signup and view all the answers

    Study Notes

    Innate Immunity Overview

    • The body's first line of defense against pathogens.
    • Consists of barriers that prevent pathogen entry and mechanisms that combat pathogens that breach these barriers.

    Anatomical Barriers

    • The most obvious component of innate immunity.
    • Comprised of epithelial layers of skin and tissues.
    • Includes mucous epithelial layers lining the respiratory, gastrointestinal, and urogenital tracts
    • Epithelial barriers prevent pathogen entry into the body's interior.
    • These barriers function as a "living plastic wrap" that protects the body from infection.

    Epithelial Barriers

    • Skin: Constitutes the outermost physical barrier, with two layers: epidermis and dermis.
    • Epidermis: Contains tightly packed epithelial cells; its outer layer consists of dead cells filled with keratin.
    • Keratin is a waterproofing protein that helps maintain skin integrity.

    Physiological Barriers

    • Include temperature, pH, and various soluble and cell-associated molecules.
    • Normal body temperature inhibits the growth of certain pathogens.
    • Gastric acidity is a barrier to infection as many ingested microorganisms cannot survive the low pH of the stomach.
    • Newborns are susceptible to diseases that adults are not due to less acidic stomach contents.

    Antimicrobial Proteins and Peptides

    • Epithelial cells secrete a broad spectrum of antimicrobial proteins and peptides to combat pathogens.
    • These molecules contribute to the defense of barrier layers against pathogens.
    • The continuous production of antimicrobial agents helps control microbial populations on these surfaces.

    Cellular Innate Response Receptors and Signaling

    • Pattern recognition receptors (PRRs) play crucial roles in detecting pathogens and activating innate immune responses.
    • PRRs bind to pathogen-associated molecular patterns (PAMPs) that trigger cellular responses.
    • Some PRRs reside on the plasma membrane, recognizing extracellular pathogens, while others are found inside cells, detecting endocytosed pathogens or cytoplasmic bacteria and viral nucleic acids.
    • PRRs ensure the recognition of PAMPs from virtually any pathogen, both extracellular and intracellular.

    Nod-Like Receptors (NLRs)

    • A large family of cytosolic proteins crucial in innate immunity.
    • Activated by intracellular PAMPs and DAMPs (damage-associated molecular patterns).
    • Contribute to activating beneficial innate immune and inflammatory responses.

    NLR Function

    • NLRs trigger autophagy, a process where the endoplasmic reticulum engulfs bacteria to form autophagosomes.
    • Autophagosomes fuse with lysosomes, leading to the destruction of bacteria.

    Inflammation: A Complex Sequence of Events

    • Tissue damage from wounds or pathogens initiates the inflammatory response.
    • LPS (lipopolysaccharide), a microbial component, can trigger inflammation through interaction with cell surface receptors.
    • The goal of inflammation is to orchestrate a specific immune response or eliminate the invader using innate immune system components.

    Cardinal Signs of Inflammation

    • Rubor (Redness): Engorged capillaries due to vasodilation.
    • Tumor (Swelling): Fluid accumulation (exudate) in the tissue causes edema.
    • Calor (Heat): Increased tissue temperature due to engorged capillaries.
    • Dolor (Pain): Stimulation of pain receptors in the skin.
    • Functio Laesa (Loss of Function): Impairment of tissue function.

    Major Events of Inflammation

    • Vasodilation: Increase in blood vessel diameter to enhance blood flow to the site of inflammation.
    • Increased Capillary Permeability: Allows fluid and cells to leak from blood vessels into the tissue.
    • Influx of Phagocytes: Movement of phagocytic cells from the blood into the tissue to ingest pathogens.

    Mediators of Inflammation

    • A complex interplay of chemical mediators initiates the inflammatory response.
    • These mediators include molecules from invading microorganisms, damaged cells, plasma enzyme systems, and white blood cells.

    Acute-Phase Proteins

    • Serum proteins that increase dramatically in tissue-damaging infections.
    • C-reactive protein (CRP) is a major acute-phase protein produced by the liver.
    • CRP binds to bacterial and fungal cell wall components, activating the complement system.

    Histamine: Key Inflammatory Mediator

    • Released by various cells in response to tissue injury.
    • Causes vasodilation and increased permeability by binding to receptors on capillaries and venules.

    Kinins: Important Inflammatory Mediators

    • Small peptides normally present in inactive form in blood plasma.
    • Activated by tissue injury, causing vasodilation, increased permeability, and pain stimulation (bradykinin).

    Blood-Clotting System

    • Enzymes from the blood-clotting system enter injured tissue, activating an enzyme cascade that forms fibrin strands.
    • Fibrin strands wall off the injured area, preventing infection spread.

    Tissue Repair and Regeneration

    • Following inflammation resolution, tissue repair and regeneration begin.

    Phagocytosis

    • A type of endocytosis, where cells engulf particulate matter, including pathogens, to form phagosomes.
    • Primarily performed by specialized cells like monocytes, neutrophils, and macrophages.
    • Other forms of endocytosis include receptor-mediated endocytosis and pinocytosis.

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    Innate Immunity PDF

    Description

    This quiz covers the fundamental aspects of innate immunity, focusing on the body's first line of defense against pathogens. It details anatomical and physiological barriers that play a critical role in preventing pathogen entry and combating infections. Understanding these components is essential for grasping the basics of immune system functionality.

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