Question 1

Which of the following best describes the difference between innate and adaptive immune defenses?

Accepted Answer

Innate defenses provide immediate, nonspecific protection, while adaptive defenses target specific pathogens and require time to activate.

Question 2

A patient with a genetic defect in keratin production would MOST likely experience which of the following consequences?

Accepted Answer

Reduced effectiveness of the skin as a physical barrier, increasing susceptibility to infection.

Question 3

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

Accepted Answer

Adherence → Engulfment (phagosome formation) → Fusion with lysosome (phagolysosome) → Digestion → Exocytosis

Question 4

Which of the following surface barriers is correctly matched with its protective mechanism?

Accepted Answer

Nasal hairs – Trap microorganisms in nasal passages.

Question 5

A patient with a severe burn loses much of their skin barrier. Which FIRST line of defense is compromised, and what is the likely consequence?

Accepted Answer

Intact epidermis; increased risk of pathogen entry and infection.

Question 6

Which of the following is NOT a cardinal sign of acute inflammation?

Accepted Answer

Fever

Question 7

During the inflammatory response, what is the primary benefit of increased vascular permeability?

Accepted Answer

It allows exudate containing clotting factors and antibodies to enter tissues, promoting healing and isolating pathogens.

Question 8

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

Accepted Answer

They are receptors on phagocytes that recognize specific patterns on microbes, triggering immune responses.

Question 9

Which of the following is a function of natural killer (NK) cells?

Accepted Answer

They induce apoptosis in virus-infected and cancer cells before the adaptive immune system is activated.

Question 10

A patient is infected with a virus. Which of the following best describes how interferons help protect neighboring cells?

Accepted Answer

Interferons stimulate neighboring cells to produce proteins that block viral replication and degrade viral RNA.

Question 11

Which pathway of complement activation requires antibodies to bind to the pathogen surface?

Accepted Answer

Classical pathway

Question 12

What is the main function of the membrane attack complex (MAC) formed during complement activation?

Accepted Answer

To form a hole in the target cell membrane, causing cell lysis.

Question 13

Which of the following best describes the process of opsonization?

Accepted Answer

The coating of pathogens by antibodies or complement proteins to enhance phagocytosis.

Question 14

A patient with tuberculosis develops granulomas in their lungs. What is the significance of this finding?

Accepted Answer

It shows that macrophages have walled off bacteria that resist digestion, potentially remaining dormant.

Question 15

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

Accepted Answer

It increases the metabolic rate, speeding up tissue repair.

Question 16

Which inflammatory chemical is released by mast cells and promotes vasodilation and increased permeability of local capillaries?

Accepted Answer

Histamine

Question 17

During phagocyte mobilization, what is the correct order of events?

Accepted Answer

Leukocytosis → Margination → Diapedesis → Chemotaxis

Question 18

Which of the following is a direct effect of C3a and other complement protein cleavage products?

Accepted Answer

They stimulate mast cells and basophils to release histamine, amplifying inflammation.

Question 19

Which of the following best explains why swelling (edema) occurs during inflammation?

Accepted Answer

Increased capillary permeability allows exudate to leak into tissues, causing local swelling.

Question 20

Which of the following is NOT a function of the inflammatory response?

Accepted Answer

Directly produces antibodies against pathogens.

Innate Immunity: The First and Second Lines of Defense

Study Guide - Practice Questions