Question 1

Which of the following BEST describes the role of keratinization in the epidermis as a barrier defense?

Accepted Answer

It forms a layer of dead, keratin-filled cells that are difficult for microbes to penetrate.

Question 2

A patient with impaired ciliary movement in the respiratory tract is MOST likely to experience which of the following consequences?

Accepted Answer

Impaired clearance of trapped pathogens due to a dysfunctional mucociliary escalator.

Question 3

Which chemical barrier is responsible for the destruction of most ingested pathogens in the stomach?

Accepted Answer

Gastric acid with a pH as low as $$1-2$$

Question 4

How does lactoferrin in body secretions contribute to innate immunity?

Accepted Answer

By binding iron and preventing bacterial growth through iron starvation.

Question 5

Which of the following is an example of a biological barrier in innate immunity?

Accepted Answer

The presence of commensal microbiota that outcompete pathogens for resources.

Question 6

A patient with impaired keratinization but an intact microbiome is MOST likely to first experience which of the following?

Accepted Answer

Increased bacterial colonization on the skin surface.

Question 7

Which of the following BEST represents a DAMP-mediated inflammatory trigger?

Accepted Answer

Extracellular ATP detection after tissue injury.

Question 8

Why are Pathogen Associated Molecular Patterns (PAMPs) ideal targets for innate immune recognition?

Accepted Answer

They are conserved and essential for microbial survival.

Question 9

Which of the following scenarios would most strongly activate endosomal Toll-like receptors (TLRs) rather than cytoplasmic PRRs?

Accepted Answer

Phagocytosis of a virus followed by detection of its nucleic acids in vesicles.

Question 10

A mutation prevents recognition of cytosolic DNA but leaves all other PRRs intact. Which infection is MOST likely to evade detection initially?

Accepted Answer

DNA virus replicating in cytoplasm.

Question 11

If vasodilation occurs but diapedesis fails during inflammation, which outcome is MOST likely?

Accepted Answer

Increased blood flow without effective immune cell infiltration.

Question 12

Which mechanism BEST explains how the microbiota prevent pathogen colonization?

Accepted Answer

Competitive exclusion and bacteriocin production.

Question 13

Which of the following is a function of lysozyme in innate immunity?

Accepted Answer

Hydrolyzing peptidoglycan in bacterial cell walls, leading to cell lysis.

Question 14

Pattern Recognition Receptors (PRRs) are essential for innate immunity because:

Accepted Answer

They allow immediate response without prior exposure to pathogens.

Question 15

Which of the following is a direct effect of histamine release during the inflammatory response?

Accepted Answer

Vasodilation and increased vascular permeability.

Question 16

A patient with a genetic defect in the complement system would MOST likely have difficulty with which of the following?

Accepted Answer

Directly lysing bacteria and opsonizing pathogens for phagocytosis.

Question 17

Which of the following is a Pathogen Associated Molecular Pattern (PAMP) detected by TLR4?

Accepted Answer

Lipopolysaccharide (LPS)

Question 18

Which of the following is MOST likely to occur if the skin’s desquamation process is impaired?

Accepted Answer

Accumulation of microbes on the skin surface.

Question 19

Which of the following is a DAMP (Damage Associated Molecular Pattern) that signals tissue injury?

Accepted Answer

Extracellular ATP

Question 20

Which of the following is a key difference between acute and chronic inflammation?

Accepted Answer

Acute inflammation is short-term and promotes healing, while chronic inflammation is long-term and can damage healthy tissue.

lec 25:Inflammation and Innate Immunity: The Body’s First Line of Defense

Study Guide - Practice Questions