Question 1

Which of the following best explains why humans are resistant to the majority of plant and animal pathogens?

Accepted Answer

Humans lack the correct chemical receptors required by most pathogens.

Question 2

Which of the following is NOT a function of the skin in innate immunity?

Accepted Answer

Production of antibodies against pathogens.

Question 3

A patient presents with an elevated eosinophil count. Which of the following is the most likely cause?

Accepted Answer

Parasitic worm infection

Question 4

Which of the following best describes the role of normal microbiota in innate immunity?

Accepted Answer

They compete with pathogens for nutrients and create an unfavorable environment for pathogen survival.

Question 5

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

Accepted Answer

Chemotaxis → Adherence → Ingestion → Maturation → Killing → Elimination

Question 6

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

Accepted Answer

It can be activated by the classical, alternative, or lectin pathways.

Question 7

A scientist observes that a patient’s cells are producing large amounts of interferon. What is the most likely reason?

Accepted Answer

The patient has a viral infection.

Question 8

Which of the following is a function of acute inflammation?

Accepted Answer

Dilation and increased permeability of blood vessels to allow phagocyte migration.

Question 9

Which of the following best describes the action of lysozyme?

Accepted Answer

It destroys the cell wall of bacteria.

Question 10

Which of the following is a distinguishing feature of natural killer (NK) lymphocytes?

Accepted Answer

They secrete toxins onto the surface of virally infected cells and tumors.

Question 11

Which of the following is a correct statement about fever?

Accepted Answer

It is triggered when pyrogens signal the hypothalamus to increase body temperature.

Question 12

Which of the following is a role of antimicrobial peptides in innate immunity?

Accepted Answer

They act against a variety of microbes by disrupting their membranes.

Question 13

Which of the following best describes the function of Toll-like receptors (TLRs)?

Accepted Answer

They bind pathogen-associated molecular patterns (PAMPs) and initiate defensive responses.

Question 14

A patient with a viral infection is found to have increased lymphocyte counts. This is most likely due to which of the following?

Accepted Answer

Lymphocytes are most involved in adaptive immunity and respond to viral infections.

Question 15

Which of the following is a correct description of the classical pathway of complement activation?

Accepted Answer

It is initiated by the binding of antibodies to antigens.

Question 16

Which of the following is a characteristic of granulocytes?

Accepted Answer

They contain large granules that stain different colors with specific dyes.

Question 17

Which of the following is a direct result of increased vascular permeability during inflammation?

Accepted Answer

More fluid and antimicrobial chemicals enter the tissues.

Question 18

Which of the following best explains why the body’s own cells are not destroyed by the complement cascade?

Accepted Answer

Proteins on body cells bind and break down activated complement proteins.

Question 19

Which of the following is a function of monocytes after they leave the blood?

Accepted Answer

They mature into macrophages and phagocytize pathogens.

Innate Immunity: The Body’s First and Second Lines of Defense

Study Guide - Practice Questions