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?

An increase in white blood cells Signup and view all the answers

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

Flagellin in bacteria Signup and view all the answers

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

Eosinophils Signup and view all the answers

Which action does NOT occur during the inflammatory response?

Decreased permeability of blood vessels Signup and view all the answers

What indicates a decrease in white blood cell count?

Leukopenia Signup and view all the answers

What is the primary effect of histamine on blood vessels?

Vasodilation and increased permeability Signup and view all the answers

Which chemical specifically intensifies the effects of histamine and kinin?

Prostaglandins Signup and view all the answers

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

Endorphins Signup and view all the answers

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

They enhance phagocytic attachment and increase permeability. Signup and view all the answers

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

They reset the body's 'thermostat' to a higher temperature. Signup and view all the answers

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

Release of chemicals from damaged cells Signup and view all the answers

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

Blood clot formation Signup and view all the answers

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

By reducing the amount of iron in the blood. Signup and view all the answers

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

Endotoxins trigger a cytokine release from the macrophage. Signup and view all the answers

Which statement best describes the role of kinins in inflammation?

They contribute to vasodilation and increased vascular permeability. Signup and view all the answers

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

Pus accumulation as a result of immune response Signup and view all the answers

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

The hypothalamus of the brain. Signup and view all the answers

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

To produce a fever response. Signup and view all the answers

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

Increased reproduction of pathogens. Signup and view all the answers

What triggers the macrophage to produce cytokines?

Endotoxins released during bacterial degradation. Signup and view all the answers

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

It degrades the bacterium in a vacuole. Signup and view all the answers

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

Margination of phagocytes Signup and view all the answers

Which process directly follows the margination of phagocytes during inflammation?

Diapedesis Signup and view all the answers

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

Release of prostaglandins Signup and view all the answers

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

Vasoconstriction of blood vessels Signup and view all the answers

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

Crisis phase Signup and view all the answers

What role do endotoxins play in the inflammatory response?

Signal the release of cytokines from phagocytes Signup and view all the answers

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

Phagocytes engulfing and destroying bacteria Signup and view all the answers

What occurs immediately after vasodilation in response to inflammation?

Swelling and redness at the injury site Signup and view all the answers

What best describes susceptibility in the context of immunity?

Lack of resistance and vulnerability to disease. Signup and view all the answers

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

Intact skin and mucous membranes Signup and view all the answers

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

By directly killing phagocytes Signup and view all the answers

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

To initiate inflammation and combat pathogens Signup and view all the answers

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

Adaptive immunity Signup and view all the answers

What mechanism allows pathogens like Mycobacterium tuberculosis to evade phagocytosis?

Prevent phagosome-lysosome fusion Signup and view all the answers

What role do antimicrobial chemicals play in innate immunity?

They destroy pathogens directly or inhibit their growth. Signup and view all the answers

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

T cells and B cells Signup and view all the answers

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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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.