Question 1

Which of the following best distinguishes innate immunity from adaptive immunity?

Accepted Answer

Innate immunity provides an immediate, non-specific response and lacks memory, while adaptive immunity is antigen-specific, slower to respond, and has memory.

Question 2

A patient presents with a bacterial infection and laboratory results show an elevated neutrophil count. This is an example of which clinical diagnostic tool?

Accepted Answer

Leukocyte differential

Question 3

Which of the following is NOT a function of the complement system in innate immunity?

Accepted Answer

Production of antibodies

Question 4

A child scrapes their knee and the area becomes red, swollen, and warm. Which phase of inflammation is primarily responsible for these cardinal signs?

Accepted Answer

Vascular changes phase

Question 5

Which of the following best describes the role of iron-binding proteins in innate immunity?

Accepted Answer

They limit pathogen growth by sequestering iron, making it unavailable for microbial use.

Question 6

Which of the following is a mechanical barrier in the first line of immune defense?

Accepted Answer

Cilia in the respiratory tract

Question 7

A patient with a viral infection is found to have increased levels of interferons. What is the primary function of interferons in innate immunity?

Accepted Answer

Signaling to neighboring cells to heighten antiviral defenses

Question 8

Which of the following best describes the organization and function of the lymphatic system in immunity?

Accepted Answer

It filters lymph, facilitates immune cell movement, and contains sites for immune response activation such as lymph nodes and spleen.

Question 9

Which leukocyte is primarily responsible for phagocytosis and is the most abundant in the blood during acute bacterial infections?

Accepted Answer

Neutrophil

Question 10

A patient develops a low-grade fever after a minor infection. Which of the following is a benefit of this fever?

Accepted Answer

It enhances interferon activity and tissue repair.

Question 11

Which of the following is a correct sequence of events in the inflammatory response?

Accepted Answer

Vascular changes → leukocyte recruitment → resolution

Question 12

Which of the following best describes the function of dendritic cells in innate immunity?

Accepted Answer

They are antigen-presenting cells that bridge innate and adaptive immunity.

Question 13

Which of the following cytokines is primarily involved in recruiting white blood cells to sites of infection?

Accepted Answer

Chemokines

Question 14

A patient with a parasitic worm infection is likely to have an increase in which type of leukocyte?

Accepted Answer

Eosinophils

Question 15

Which of the following is a chemical barrier in the first line of immune defense?

Accepted Answer

Lysozyme in saliva

Question 16

Which of the following statements about natural killer (NK) cells is correct?

Accepted Answer

They are lymphocytes involved in innate immunity and kill virus-infected or abnormal cells.

Question 17

A patient with a genetic deficiency in complement proteins is most likely to experience which of the following?

Accepted Answer

Impaired opsonization and increased susceptibility to bacterial infections

Question 18

Which of the following best explains why the skin is considered a physical barrier in the first line of defense?

Accepted Answer

It is composed of tightly packed epithelial cells that prevent pathogen entry.

Question 19

Which of the following is a correct statement about the three lines of immune defense?

Accepted Answer

The second line includes leukocytes and molecular defenses such as cytokines and complement.

Question 20

A patient with a high fever (above 40°C) is at risk for which of the following complications?

Accepted Answer

Potential tissue and organ damage due to excessive temperature

Innate Immunity: The Body's First Lines of Defense

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