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Ch. 11 - Innate Immunity
Norman-McKay- Microbiology: Basic and Clinical Principles 2nd Edition
Norman-McKay2nd EditionMicrobiology: Basic and Clinical PrinciplesISBN: 9780137661619Not the one you use?Change textbook
All textbooksNorman-McKay 2nd EditionCh. 11 - Innate ImmunityProblem 21
Chapter 11, Problem 21

Which of the following is a chemical defense found in tears? Select all that apply.
a. Water
b. Lysozyme
c. Antimicrobial peptides
d. Neutrophils

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1
Understand that tears provide a chemical defense as part of the body's innate immune system to protect the eyes from microbial infection.
Identify the components listed that are chemical substances versus cellular components. Chemical defenses are molecules, while cells like neutrophils are part of the cellular immune response.
Recognize that water (option a) is primarily a physical medium and does not have antimicrobial properties by itself, so it is not considered a chemical defense.
Recall that lysozyme (option b) is an enzyme present in tears that breaks down bacterial cell walls, making it a key chemical defense.
Know that antimicrobial peptides (option c) are small proteins that can disrupt microbial membranes and are also part of the chemical defenses in tears, whereas neutrophils (option d) are immune cells and not a chemical defense.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Chemical Defenses in Tears

Tears contain various chemical substances that protect the eyes from microbial infection. These include enzymes and peptides that can directly kill or inhibit the growth of pathogens, forming part of the innate immune system.
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Lysozyme

Lysozyme is an enzyme abundant in tears that breaks down the peptidoglycan layer of bacterial cell walls, especially in Gram-positive bacteria, leading to their destruction. It is a key antimicrobial agent in the chemical defense of mucosal surfaces.
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Antimicrobial Peptides

Antimicrobial peptides are small proteins found in tears that disrupt microbial membranes, causing cell death. They provide broad-spectrum defense against bacteria, fungi, and viruses, complementing other chemical defenses like lysozyme.
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Related Practice
Textbook Question

Which of the following shows a correct chronological order of events in inflammation?

a. Neutrophil recruitment, macrophage recruitment, vascular changes, resolution

b. Vascular changes, resolution, neutrophil recruitment, macrophage recruitment

c. Vascular changes, macrophage recruitment, neutrophil recruitment, resolution

d. Vascular changes, macrophage recruitment, resolution, neutrophil recruitment

e. Vascular changes, neutrophil recruitment, macrophage recruitment, resolution

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Textbook Question

Why is innate immunity considered a generalized defense?

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Textbook Question

Select all the false statements about fever.

a. It is generated by pyrogens

b. It is an innate immune defense

c. It is accompanied by a decrease in metabolism

d. It can be reduced by anti-inflammatory drugs

e. It can accompany inflammation

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Textbook Question

Which of the following are formed elements of the blood? Select all that apply.

a. Platelet

b. Leukocyte

c. Plasma

d. Erythrocyte

e. Complement proteins

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Textbook Question

Match the following fever terms to their proper definition; not all definitions will be used.

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