Question 1

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

Accepted Answer

TLRs attach to pathogen-associated molecular patterns (PAMPs) and induce cytokine release.

Question 2

A patient presents with a white blood cell count of 2,500/μl. Which of the following is the most likely cause?

Accepted Answer

Viral infection or severe bacterial infection

Question 3

Which physical factor of the first line of defense is most responsible for preventing microbial penetration into the lower respiratory tract?

Accepted Answer

Ciliary escalator

Question 4

Which chemical factor found in tears, saliva, and urine is responsible for destroying bacterial cell walls?

Accepted Answer

Lysozyme

Question 5

Normal microbiota protect the host by all of the following EXCEPT:

Accepted Answer

Directly phagocytosing invading bacteria

Question 6

Which of the following is an example of an opportunistic pathogen among the normal microbiota?

Accepted Answer

Escherichia coli

Question 7

Which leukocyte is most active in the early stages of a bacterial infection and is highly phagocytic?

Accepted Answer

Neutrophil

Question 8

During inflammation, which process describes the movement of phagocytes through the walls of blood vessels to reach the site of infection?

Accepted Answer

Diapedesis

Question 9

Which of the following is a function of acute-phase proteins released during inflammation?

Accepted Answer

Inducing local and systemic inflammatory responses

Question 10

A cytokine storm is most likely to result in which of the following clinical outcomes?

Accepted Answer

Significant tissue damage and multiorgan dysfunction

Question 11

Which of the following statements about fever is CORRECT?

Accepted Answer

Fever can enhance the activity of phagocytes and T cells.

Question 12

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

Accepted Answer

Classical pathway

Question 13

What is the main outcome of complement activation that directly leads to the lysis of microbial cells?

Accepted Answer

Formation of membrane attack complex (MAC)

Question 14

Which of the following is a mechanism by which some bacteria evade the complement system?

Accepted Answer

Having capsules that prevent complement activation

Question 15

Interferon-alpha ($$\mathrm{IFN}-\alpha) $$and interferon-beta ($$\mathrm{IFN}-\beta) $$are produced by viral-infected host cells and function by:

Accepted Answer

Inducing nearby cells to produce antiviral proteins (AVPs)

Question 16

Which iron-binding protein is found in blood and tissue fluids and helps limit pathogen growth by sequestering iron?

Accepted Answer

Transferrin

Question 17

Antimicrobial peptides such as defensins and cathelicidins protect the host by:

Accepted Answer

Forming pores in microbial membranes and inhibiting cell wall synthesis

Question 18

A patient with sickle cell trait is less susceptible to malaria due to which type of resistance?

Accepted Answer

Genetic resistance

Question 19

Which of the following best explains why the elderly are more susceptible to infectious diseases?

Accepted Answer

Their immune system function declines with age.

Question 20

Which process involves coating a microorganism with serum proteins to enhance phagocytosis?

Accepted Answer

Opsonization

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

Study Guide - Practice Questions