Question 1

Which of the following best describes the primary function of skin as a surface membrane barrier in the immune system?

Accepted Answer

It forms a mechanical barrier that prevents entry of pathogens and other harmful substances.

Question 2

A patient with a genetic defect in Toll-like receptors (TLRs) would most likely have difficulty with which aspect of innate immunity?

Accepted Answer

Recognizing invaders and initiating inflammation.

Question 3

Which of the following is NOT a function of natural killer (NK) cells?

Accepted Answer

Phagocytosis of bacteria.

Question 4

During an acute inflammatory response, which of the following is a direct physiological effect of histamine release?

Accepted Answer

Increased capillary permeability.

Question 5

A child presents with frequent respiratory infections. Upon examination, it is found that their nasal passages do not effectively filter and trap microorganisms. Which first line of defense is most likely compromised?

Accepted Answer

Surface membrane barriers.

Question 6

Which of the following best explains why fever can be beneficial during an infection?

Accepted Answer

It increases the metabolic rate of tissue cells, enhancing repair processes.

Question 7

Interferons are important in the immune response because they:

Accepted Answer

Block viral replication in uninfected cells.

Question 8

A granuloma forms in tissue as a result of:

Accepted Answer

Macrophages containing bacteria that resist digestion, surrounded by other immune cells and a fibrous capsule.

Question 9

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

Accepted Answer

Adherence to pathogen, formation of phagosome, fusion with lysosome, digestion of pathogen.

Question 10

Which of the following best describes the role of complement proteins in innate immunity?

Accepted Answer

They enhance opsonization, promote inflammation, and lyse microorganisms.

Question 11

A patient with a severe burn loses much of their skin barrier. Which of the following is the most immediate risk to their immune defense?

Accepted Answer

Increased susceptibility to pathogen entry due to loss of mechanical barrier.

Question 12

Which of the following is a hallmark sign of acute inflammation?

Accepted Answer

Redness and heat at the site of injury.

Question 13

Which of the following best explains why the acidic pH of the stomach is an effective defense mechanism?

Accepted Answer

It destroys most pathogens through concentrated hydrochloric acid and protein-digesting enzymes.

Question 14

A patient is diagnosed with a deficiency in complement protein C3. Which of the following immune processes would be most directly impaired?

Accepted Answer

Opsonization and lysis of pathogens.

Question 15

Which of the following is a real-world example of the first line of defense failing, leading to activation of internal defenses?

Accepted Answer

A cut on the skin allows bacteria to enter, triggering inflammation.

Question 16

Which of the following best describes the role of opsonins in phagocytosis?

Accepted Answer

They coat pathogens, enhancing their recognition and ingestion by phagocytes.

Question 17

A patient with multiple sclerosis (MS) is sometimes treated with interferons. What is the primary reason for this therapy?

Accepted Answer

Interferons modulate the immune response and have antiviral effects.

Question 18

Which of the following equations best represents the relationship between body temperature (T), metabolic rate (M), and rate of tissue repair (R) during fever?

Accepted Answer

$$M \propto T$$ and $$R \propto M$$

Question 19

Which of the following is a correct statement about the difference between innate and adaptive immunity?

Accepted Answer

Innate immunity responds to pathogens non-specifically, while adaptive immunity targets specific antigens.

Question 20

A patient with a chronic bacterial infection develops a walled-off area of pus surrounded by fibrous tissue. What is this structure called, and what is its significance?

Accepted Answer

Granuloma; it contains bacteria that resist digestion and prevents their spread.

Innate Defenses of the Immune System: Structure and Function

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