Ch.16 Review
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Questions and Answers

What are Toll-like receptors (TLRs) primarily responsible for in innate immunity?

  • Enclosing the infected area with tissue fibers
  • Increasing blood flow to tissues
  • Attaching to pathogenic microbes (correct)
  • Producing toxins against viruses

Which of the following is NOT a characteristic of inflammation?

  • Rapid cell division (correct)
  • Heat
  • Swelling (edema)
  • Redness

What is the role of neutrophils in the immune response?

  • Phagocytosis (correct)
  • Killing parasitic worms
  • Releasing histamine
  • Producing antibodies

What does leukocytosis indicate?

<p>An increase in white blood cells (A)</p> Signup and view all the answers

Which of the following components are recognized as pathogen-associated molecular patterns (PAMPs)?

<p>Flagellin in bacteria (D)</p> Signup and view all the answers

Which type of white blood cell is primarily involved in killing parasites?

<p>Eosinophils (C)</p> Signup and view all the answers

Which action does NOT occur during the inflammatory response?

<p>Decreased permeability of blood vessels (A)</p> Signup and view all the answers

What indicates a decrease in white blood cell count?

<p>Leukopenia (D)</p> Signup and view all the answers

What is the primary effect of histamine on blood vessels?

<p>Vasodilation and increased permeability (C)</p> Signup and view all the answers

Which chemical specifically intensifies the effects of histamine and kinin?

<p>Prostaglandins (A)</p> Signup and view all the answers

Which of the following chemicals is NOT released by damaged cells?

<p>Endorphins (A)</p> Signup and view all the answers

Which of the following describes the role of leukotrienes in inflammation?

<p>They enhance phagocytic attachment and increase permeability. (A)</p> Signup and view all the answers

What role do cytokines play in the immune response initiated by macrophages?

<p>They reset the body's 'thermostat' to a higher temperature. (D)</p> Signup and view all the answers

What event occurs immediately following tissue damage in the inflammatory process?

<p>Release of chemicals from damaged cells (A)</p> Signup and view all the answers

Which step follows the release of inflammatory chemicals in the process of inflammation?

<p>Blood clot formation (C)</p> Signup and view all the answers

How does fever contribute to the body's defense against pathogens?

<p>By reducing the amount of iron in the blood. (D)</p> Signup and view all the answers

What is the outcome of a macrophage ingesting a gram-negative bacterium?

<p>Endotoxins trigger a cytokine release from the macrophage. (B)</p> Signup and view all the answers

Which statement best describes the role of kinins in inflammation?

<p>They contribute to vasodilation and increased vascular permeability. (A)</p> Signup and view all the answers

What is the outcome of the inflammatory process involving abscess formation?

<p>Pus accumulation as a result of immune response (D)</p> Signup and view all the answers

Where do the cytokines produced by macrophages travel to exert their effect?

<p>The hypothalamus of the brain. (B)</p> Signup and view all the answers

What is the primary function of the prostaglandins produced in response to cytokines?

<p>To produce a fever response. (A)</p> Signup and view all the answers

Which of the following processes is NOT associated with the body's fever response?

<p>Increased reproduction of pathogens. (D)</p> Signup and view all the answers

What triggers the macrophage to produce cytokines?

<p>Endotoxins released during bacterial degradation. (A)</p> Signup and view all the answers

What is the initial action taken by a macrophage once it ingests a gram-negative bacterium?

<p>It degrades the bacterium in a vacuole. (B)</p> Signup and view all the answers

What is the first step in the process of inflammation as described?

<p>Margination of phagocytes (D)</p> Signup and view all the answers

Which process directly follows the margination of phagocytes during inflammation?

<p>Diapedesis (D)</p> Signup and view all the answers

During a fever, what triggers the hypothalamus to reset to a higher temperature?

<p>Release of prostaglandins (C)</p> Signup and view all the answers

What physiological change occurs when the body temperature rises during a fever?

<p>Vasoconstriction of blood vessels (A)</p> Signup and view all the answers

What phase follows the resolution of an infection, characterized by a drop in body temperature?

<p>Crisis phase (B)</p> Signup and view all the answers

What role do endotoxins play in the inflammatory response?

<p>Signal the release of cytokines from phagocytes (C)</p> Signup and view all the answers

Which of the following describes the process of phagocytosis in inflammation?

<p>Phagocytes engulfing and destroying bacteria (C)</p> Signup and view all the answers

What occurs immediately after vasodilation in response to inflammation?

<p>Swelling and redness at the injury site (A)</p> Signup and view all the answers

What best describes susceptibility in the context of immunity?

<p>Lack of resistance and vulnerability to disease. (B)</p> Signup and view all the answers

Which of the following is considered a first line of defense in the body?

<p>Intact skin and mucous membranes (B)</p> Signup and view all the answers

How do leukocidins contribute to microbial evasion of the immune system?

<p>By directly killing phagocytes (D)</p> Signup and view all the answers

What is the primary role of the second line of defense in the immune system?

<p>To initiate inflammation and combat pathogens (D)</p> Signup and view all the answers

Which type of immunity is characterized by the body's ability to respond to specific pathogens?

<p>Adaptive immunity (A)</p> Signup and view all the answers

What mechanism allows pathogens like Mycobacterium tuberculosis to evade phagocytosis?

<p>Prevent phagosome-lysosome fusion (B)</p> Signup and view all the answers

What role do antimicrobial chemicals play in innate immunity?

<p>They destroy pathogens directly or inhibit their growth. (D)</p> Signup and view all the answers

Which cell types are specifically involved in the adaptive immune response?

<p>T cells and B cells (C)</p> Signup and view all the answers

Flashcards

Innate Immunity

The body's first line of defense against pathogens, providing general protection against a broad range of threats.

Resistance

The body's ability to ward off disease.

Susceptibility

The lack of resistance, making someone vulnerable to disease.

First Line of Defense

Barriers that prevent pathogens from entering the body (e.g., skin, mucous membranes, stomach acid).

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Second Line of Defense

Internal defenses that combat pathogens that break through the first line, including phagocytes and inflammation.

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Pathogen

A disease-causing agent, such as a bacterium or virus.

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Phagocytes

Cells that engulf and destroy pathogens.

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Inflammation

The body's response to tissue injury, characterized by redness, swelling, heat, and pain.

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Toll-like receptors (TLRs)

Protein receptors on the surface of immune cells like neutrophils, macrophages, and dendritic cells. They recognize specific patterns on pathogens, called PAMPs, triggering an immune response.

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Pattern-recognition receptors (PRRs)

A broad category of receptors, including TLRs, that recognize specific patterns on pathogens. They play a crucial role in initiating the innate immune response.

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Pathogen-associated molecular patterns (PAMPs)

Specific molecules found on pathogens but not on mammalian cells, recognized by PRRs. Examples include lipopolysaccharide (LPS) from bacteria and viral DNA.

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What do TLRs and PRRs do?

TLRs and PRRs bind to PAMPs on pathogens, activating the innate immune system. This triggers the release of signaling molecules and activates immune cells to fight the infection.

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Neutrophils

A type of white blood cell (WBC) that is a key player in the innate immune response. They are highly phagocytic, engulfing and destroying pathogens.

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Leukocytosis

An increase in the number of white blood cells in the bloodstream, often a sign of infection or inflammation.

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Vasodilation

The widening of blood vessels during inflammation, allowing more blood flow to the affected area and bringing in immune cells.

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Chemicals Released by Damaged Cells

When cells are damaged, they release chemicals like histamine, kinins, prostaglandins, and leukotrienes. These chemicals trigger various responses to protect the body.

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Histamine's Role

Histamine contributes to vasodilation (widening of blood vessels) and increased blood vessel permeability, allowing fluid and immune cells to reach the injured area.

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Kinins' Function

Kinins, similar to histamine, cause vasodilation and increased blood vessel permeability, facilitating the immune response.

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Prostaglandins' Effect

Prostaglandins amplify the effects of histamine and kinins, further promoting vasodilation and permeability, ultimately leading to inflammation.

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Leukotrienes' Function

Leukotrienes play a role in increasing blood vessel permeability and promoting phagocyte (immune cell) attachment to damaged tissue.

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What is Vasodilation?

Vasodilation is the widening of blood vessels, allowing for increased blood flow to the injured area.

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What is Increased Permeability?

Increased permeability means making blood vessels 'leaky', allowing immune cells and other substances to move from the bloodstream to the injured tissue.

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Inflammation's Purpose

Inflammation is a protective process that helps the body heal after injury or infection. It brings immune cells and other components to the area to fight pathogens and repair damaged tissue.

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Margination

Phagocytes (like neutrophils) stick to the inner lining of blood vessels (endothelium).

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Diapedesis

Phagocytes squeeze between endothelial cells and enter the injured tissue.

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Fever

An abnormally high body temperature caused by the hypothalamus resetting to a higher set point due to substances released by phagocytes.

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Hypothalamus

The part of the brain that acts like the body's thermostat, regulating body temperature.

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Prostaglandins

Substances released by the hypothalamus that reset the thermostat to a higher temperature, causing fever.

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Crisis

The phase when fever subsides after infection resolves.

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Endotoxin

A toxic component of the outer membrane of some bacteria, especially gram-negative bacteria. It is released when the bacteria die or are broken down.

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Macrophage

A type of white blood cell (WBC) that engulfs and destroys pathogens, cellular debris, and other foreign substances in the body.

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Cytokines

Small signaling molecules released by immune cells, like macrophages, to communicate with other cells and coordinate immune responses.

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How does endotoxin trigger fever?

When a macrophage engulfs a gram-negative bacterium, the endotoxin is released. This triggers the macrophage to produce cytokines. These cytokines travel to the hypothalamus in the brain, causing it to release prostaglandins that reset the body's 'thermostat' to a higher temperature.

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What is the role of the hypothalamus in fever?

The hypothalamus acts as the body's thermostat. When stimulated by cytokines, it releases prostaglandins, which reset the body's temperature to a higher level, causing fever.

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How does fever fight infection?

Fever helps fight infection by reducing iron levels in the blood, which slows the growth of pathogens. It also increases the activity of phagocytic white blood cells.

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What is the benefit of fever?

Fever helps protect against infection by creating conditions that are unfavorable for the growth of bacteria and fungi.

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Study Notes

Innate Immunity: Nonspecific Defenses of the Host

  • Innate immunity is the body's first and second line of defense against pathogens
  • Resistance is the body's ability to ward off disease
  • Resistance factors include: skin, stomach acid, and antimicrobial chemicals
  • Pathogenic microbes and host resistance determine disease contraction
  • Immunity (resistance) is the body's ability to ward off diseases
    • Innate immunity
    • Adaptive immunity

Body Defenses Against Infection

  • Pathogens are disease-causing agents
  • The body has three lines of defense against infection
    • Nonspecific defenses (first and second lines of defense) defend against many pathogens
    • Specific defenses (adaptive immunity, third line of defense) target specific pathogens with lymphocytes

Overview of Body Defenses

  • Innate Immunity (First Line of Defense):
    • Intact skin
    • Mucous membranes and their secretions
    • Normal microbiota
  • Innate Immunity (Second Line of Defense):
    • Phagocytes (neutrophils, eosinophils, dendritic cells, and macrophages)
    • Inflammation
    • Fever
    • Antimicrobial substances
  • Adaptive Immunity (Third Line of Defense):
    • Specialized lymphocytes (T cells and B cells)
    • Antibodies

Microbial Evasion of Phagocytosis

  • Pathogens can evade phagocytosis in several ways
  • Examples include inhibiting adherence, killing phagocytes, lysing phagocytes, escaping the phagosome, preventing phagosome-lysosome fusion, and surviving in phagolysosomes

Recognition of Pathogens by Immune Cells

  • Toll-like receptors (TLRs) and Pattern-recognition receptors (PRRs) are protein receptors on defensive host cells, such as neutrophils, macrophages, and dendritic cells
  • TLRs and PRRs recognize pathogen-associated molecular patterns (PAMPs) on pathogens

TLRs and PAMPs

  • TLRs recognize specific PAMPs (patterns) on pathogens
  • Different TLRs recognize different PAMPs
  • Recognition triggers an innate immune response

Differential White Cell Count

  • Normal proportions of different white blood cells in a sample
  • Includes percentages for neutrophils, basophils, eosinophils, monocytes, and lymphocytes
  • Variations in counts can indicate infection or other issues

Inflammation

  • A tissue response to a pathogen
  • Characterized by redness, swelling, heat, and pain
  • Major processes in inflammation:
    • Vasodilation (blood vessel widening)
    • Increased permeability of blood vessels
    • Invasion of white blood cells into the affected area
    • Formation of tissue fibers to prevent pathogen spread

Chemicals Released During Inflammation

  • Histamine
  • Kinins
  • Prostaglandins
  • Leukotrienes

The Process of Inflammation

  • Tissue damage initiates a chain of events
  • Chemicals like histamine, kinins, prostaglandins, leukotrienes, and cytokines are released
  • This causes vasodilation and increased permeability
  • Blood clots form, abscesses form, and phagocytes migrate to infected areas

Fever

  • Abnormally high body temperature
  • Hypothalamus (body's thermostat) is normally set at 37°C (98.6°F)
  • Gram-negative endotoxins trigger phagocytes to release cytokines, leading to the hypothalamus releasing prostaglandins
  • The hypothalamus increases body temperature
  • Vasoconstriction conserves heat
  • Increased metabolism
  • Shivering also raises body temperature
  • When infection subsides, vasodilation and sweating occur, lowering body temperature

Endotoxins and the Pyrogenic Response

  • Endotoxins cause macrophages to release cytokines, which trigger prostaglandins' release
  • This causes the hypothalamus to reset the body's temperature, resulting in fever
  • The fever response helps eliminate/slow the infection

Fever's Protective Effects

  • Fever reduces iron in the blood, hindering pathogen growth
  • Phagocytic white blood cells become more efficient at higher temperatures

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Ch 16 Notes - Innate Immunity PDF

Description

Test your knowledge on innate immunity, the body's first and second lines of defense against pathogens. Explore the resistance factors and the body's various defenses against infections. This quiz covers key concepts and mechanisms of the immune system.

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