$$\text{Peptidoglycan} \xrightarrow{\text{Lysozyme}} \text{Disrupted cell wall}$$

$$\text{Antigen} + \text{Antibody} \rightarrow \text{C1 activation}$$

$$\text{Pyrogens} \xrightarrow{\text{Hypothalamus}} \text{Increased body temperature}$$

Question 1

Which of the following is NOT a mechanism by which the skin acts as a first-line defense against pathogens?

Accepted Answer

High skin pH promotes bacterial growth

Question 2

A patient presents with elevated eosinophil counts. Which condition is most likely indicated by this lab result?

Accepted Answer

Parasitic worm infestation

Question 3

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

Accepted Answer

They compete with pathogens for nutrients and create unfavorable environments

Question 4

During phagocytosis, which step involves the movement of phagocytes toward the site of infection?

Accepted Answer

Chemotaxis

Question 5

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

Accepted Answer

Complement activation results in lysis of foreign cells

Question 6

A scientist is studying the effects of lysozyme on bacteria. Which equation best represents the action of lysozyme on bacterial cell walls?

Accepted Answer

$$	ext{Peptidoglycan} \xrightarrow{	ext{Lysozyme}} 	ext{Disrupted cell wall}$$

Question 7

Which of the following is a function of acute inflammation?

Accepted Answer

Facilitates tissue repair and increases blood vessel permeability

Question 8

Which cell type is most involved in adaptive immunity?

Accepted Answer

Lymphocytes

Question 9

A viral infection triggers the release of interferons. What is the primary effect of interferons?

Accepted Answer

They inhibit the spread of viral infections by signaling neighboring cells

Question 10

Which of the following equations best represents the activation of complement via the classical pathway?

Accepted Answer

$$	ext{Antigen} + 	ext{Antibody} ightarrow 	ext{C1 activation}$$

Question 11

Which of the following is a characteristic of the body's second line of defense?

Accepted Answer

It operates only when pathogens penetrate the first line of defense

Question 12

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 13

Which equation best represents the effect of pyrogens on body temperature?

Accepted Answer

$$	ext{Pyrogens} \xrightarrow{	ext{Hypothalamus}} 	ext{Increased body temperature}$$

Question 14

Which of the following is a plausible outcome if the complement cascade is not properly inactivated on host cells?

Accepted Answer

Host cells would be lysed by membrane attack complexes

Question 15

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

Accepted Answer

Chemotaxis → Adherence → Ingestion → Maturation → Killing → Elimination

Question 16

Which of the following is a function of neutrophil extracellular traps (NETs)?

Accepted Answer

They bind to and kill bacteria

Question 17

Which of the following best describes microbial antagonism?

Accepted Answer

Normal microbiota compete with pathogens for nutrients and space

Question 18

Which of the following is a plausible effect of increased vascular permeability during inflammation?

Accepted Answer

More antimicrobial chemicals and clotting proteins enter the tissue

Question 19

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

Accepted Answer

It is triggered by antigen-antibody complexes

Question 20

Which of the following is a characteristic symptom of acute inflammation?

Accepted Answer

Redness, heat, swelling, and pain

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

Study Guide - Practice Questions