Question 1

Which of the following is NOT considered a physical (mechanical) factor in the body's first line of defense against microbes?

Accepted Answer

Lysozyme in tears

Question 2

A patient with a genetic deficiency in complement protein C3 would most likely experience which of the following problems?

Accepted Answer

Impaired opsonization and increased susceptibility to bacterial infections

Question 3

Which leukocyte is primarily responsible for phagocytosis and is the most abundant in the blood during a bacterial infection?

Accepted Answer

Neutrophil

Question 4

During the process of phagocytosis, which stage involves the fusion of the phagosome with lysosomes to form a phagolysosome?

Accepted Answer

Digestion

Question 5

Which chemical factor found in sweat helps to inhibit microbial growth by lowering skin pH?

Accepted Answer

Lactic acid

Question 6

Which of the following best describes the role of Toll-like receptors (TLRs) in innate immunity?

Accepted Answer

They recognize pathogen-associated molecular patterns (PAMPs) and activate immune responses.

Question 7

A child develops a fever after a bacterial infection. Which cytokine is most directly responsible for inducing fever by acting on the hypothalamus?

Accepted Answer

Interleukin-1 (IL-1)

Question 8

Which of the following is a function of inflammation?

Accepted Answer

To confine and destroy microbes and initiate tissue repair

Question 9

Which antimicrobial substance is produced in response to viral infections and helps protect neighboring cells from viral replication?

Accepted Answer

Interferon

Question 10

Which of the following is NOT an outcome of complement activation?

Accepted Answer

Antibody production

Question 11

Which pathway of complement activation is initiated by the binding of antibodies to antigens?

Accepted Answer

Classical pathway

Question 12

Which of the following best explains why normal microbiota are considered part of the body's nonspecific defenses?

Accepted Answer

They compete with pathogens for nutrients and alter the environment to inhibit pathogen growth.

Question 13

A patient is infected with Shigella. Which microbial strategy does Shigella use to evade phagocytosis?

Accepted Answer

Escaping phagosome

Question 14

Which of the following is a chemical factor that destroys bacterial cell walls and is found in tears, saliva, and perspiration?

Accepted Answer

Lysozyme

Question 15

Which leukocyte is most likely to be elevated in a patient with a parasitic infection?

Accepted Answer

Eosinophil

Question 16

Which stage of phagocytosis involves the movement of phagocytes toward the site of infection in response to chemical signals?

Accepted Answer

Chemotaxis

Question 17

Which of the following best describes the function of antimicrobial peptides?

Accepted Answer

They inhibit cell wall synthesis and form pores in microbial membranes.

Question 18

Which of the following is a benefit of fever during infection?

Accepted Answer

It increases the production of transferrins that sequester iron, inhibiting bacterial growth.

Question 19

Which of the following equations correctly represents the formation of the membrane attack complex (MAC) in the classical pathway of complement activation?

Accepted Answer

$$C5b + C6 + C7 + C8 + C9 \rightarrow MAC$$

Question 20

Which of the following statements about interferons is TRUE?

Accepted Answer

Interferons are cell-specific, not virus-specific, and protect neighboring cells from viral replication.

Innate Immunity: Nonspecific Defenses of the Host (Chapter 16) – Study Notes

Study Guide - Practice Questions

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