Question 1

Which of the following is NOT a characteristic of the innate immune system?

Accepted Answer

It is pathogen-specific and has memory.

Question 2

Which structure acts as the most significant first line of defense against infection?

Accepted Answer

Skin

Question 3

The dermis layer of the skin provides defense against pathogens primarily by:

Accepted Answer

Containing tough fibers of collagen for strength and pliability

Question 4

Sweat glands contribute to the chemical defense of the skin by:

Accepted Answer

Secreting salt and antimicrobial peptides that inhibit pathogen growth

Question 5

Which of the following best describes the role of lysozyme in innate immunity?

Accepted Answer

It destroys the cell wall of bacteria.

Question 6

How do mucous membranes in the respiratory tract help prevent infection?

Accepted Answer

By producing cilia that propel mucus and trapped pathogens out of the lungs

Question 7

Normal microbiota protect the host from pathogens by all of the following EXCEPT:

Accepted Answer

Directly lysing viral particles in the bloodstream

Question 8

Which protein in plasma is responsible for transporting iron and making it unavailable to microbes?

Accepted Answer

Transferrin

Question 9

A patient’s CBC (Complete Blood Count) shows an increased number of eosinophils. This is most likely indicative of:

Accepted Answer

An allergy or parasitic worm infection

Question 10

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

Accepted Answer

Chemotaxis → Adherence → Ingestion → Maturation → Killing → Elimination

Question 11

Which immune cell is capable of killing microbes without phagocytosis by secreting toxins onto the surface of infected cells and tumors?

Accepted Answer

Natural Killer (NK) lymphocyte

Question 12

Neutrophils can kill bacteria by producing extracellular fibers called NETs. What is the main function of these NETs?

Accepted Answer

To bind and kill bacteria

Question 13

Which of the following statements about interferons is TRUE?

Accepted Answer

They nonspecifically inhibit the spread of viral infections.

Question 14

The complement system can be activated by all of the following pathways EXCEPT:

Accepted Answer

Phagocytic pathway

Question 15

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

Accepted Answer

Fever

Question 16

Fever is defined as a body temperature over $$37^\circ C$$ $$(98.6^\circ F). $$Which of the following is a physiological effect of fever?

Accepted Answer

Inhibits the growth of some microorganisms

Question 17

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

Accepted Answer

They are integral membrane proteins that bind pathogen-associated molecular patterns (PAMPs) and initiate defensive responses.

Question 18

A patient presents with a viral infection. Which change in white blood cell count would you expect to see in their CBC?

Accepted Answer

Increased lymphocytes

Question 19

Which of the following is a function of antimicrobial peptides secreted by sweat glands?

Accepted Answer

They form permeable channels in bacterial cytoplasmic membranes.

Question 20

Which of the following is a multi-step process that involves chemotaxis, adherence, ingestion, maturation, killing, and elimination?

Accepted Answer

Phagocytosis

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

Study Guide - Practice Questions