Question 1

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

Accepted Answer

TLRs recognize pathogen-associated molecular patterns (PAMPs) and trigger cytokine release.

Question 2

A patient presents with a high white blood cell count. Which of the following is the most likely cause?

Accepted Answer

Bacterial infection

Question 3

Which of the following is NOT a physical factor involved in the first line of defense against pathogens?

Accepted Answer

Lysozyme in tears

Question 4

Which of the following statements about the complement system is TRUE?

Accepted Answer

It consists of over 30 proteins that act in a cascade to destroy microbes.

Question 5

A bacterial pathogen produces a capsule containing sialic acid. What is the most likely effect on the host's immune response?

Accepted Answer

Inhibition of complement activation and reduced opsonization

Question 6

Which of the following leukocytes is most abundant in normal blood and acts as a 'first responder' during bacterial infection?

Accepted Answer

Neutrophil

Question 7

Which process describes the movement of phagocytes from the bloodstream into infected tissues?

Accepted Answer

Diapedesis

Question 8

Which of the following is a function of fever in the immune response?

Accepted Answer

Slows the growth of pathogens and enhances the activity of phagocytes and T cells

Question 9

A patient with a genetic deficiency in C3 complement protein would be most susceptible to which of the following?

Accepted Answer

Recurrent bacterial infections

Question 10

Which of the following best explains why normal microbiota are important for innate immunity?

Accepted Answer

They compete with pathogens for nutrients and space, and may produce substances harmful to pathogens.

Question 11

Which chemical factor found in tears, saliva, and sweat is responsible for breaking down bacterial cell walls?

Accepted Answer

Lysozyme

Question 12

Which of the following is a correct sequence of events in phagocytosis?

Accepted Answer

Chemotaxis → Adherence → Ingestion → Digestion

Question 13

Which of the following is a vasoactive mediator released by mast cells that causes vasodilation and increased vascular permeability during inflammation?

Accepted Answer

Histamine

Question 14

Which of the following best describes the function of interferons (IFN-α and IFN-β) in viral infections?

Accepted Answer

They induce neighboring cells to produce antiviral proteins that inhibit viral replication.

Question 15

A patient with a fever of 40°C is at risk for which of the following complications if the fever continues to rise?

Accepted Answer

Seizures and coma

Question 16

Which of the following is a correct description of opsonization?

Accepted Answer

The coating of a microbe with serum proteins to enhance phagocytosis.

Question 17

Which of the following antimicrobial substances is produced by neutrophils and macrophages and can form pores in microbial membranes?

Accepted Answer

Defensins

Question 18

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

Accepted Answer

Their immune systems are less developed or weakened.

Question 19

Which of the following is a function of the lymphatic system in immunity?

Accepted Answer

It transports microbes to lymph nodes where immune cells can destroy them.

Question 20

A patient is given a probiotic supplement after antibiotic therapy. What is the most likely benefit of this intervention?

Accepted Answer

Restoration of normal microbiota to prevent overgrowth of harmful microbes

Innate Immunity: Nonspecific Defenses of the Host

Study Guide - Practice Questions

Study Guide - Flashcards