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, develops memory, and takes several days to respond.

Question 2

A patient presents with a bacterial infection. Laboratory results show an elevated neutrophil count. What is the most likely explanation for this finding?

Accepted Answer

Neutrophils are the main phagocytic cells in innate immunity and increase in response to bacterial infections.

Question 3

Which of the following is an example of a mechanical first-line defense against pathogens?

Accepted Answer

The movement of cilia in the respiratory tract to trap and remove microbes

Question 4

Which statement best describes the function of the complement system in innate immunity?

Accepted Answer

It is a series of proteins that, when activated, lead to opsonization, cytolysis, and inflammation.

Question 5

A researcher is studying the effects of iron-binding proteins on bacterial growth. Which of the following best explains how these proteins contribute to innate immunity?

Accepted Answer

They sequester iron, making it unavailable to pathogens and thereby limiting their growth.

Question 6

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

Accepted Answer

Fever

Question 7

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

Accepted Answer

They signal neighboring cells to heighten their 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 lymph nodes that are sites of immune response activation.

Question 9

Which leukocyte is most likely to increase in number during a parasitic infection and is also involved in allergic responses?

Accepted Answer

Eosinophils

Question 10

A patient develops a low-grade fever after surgery. Which of the following best explains the potential benefit of this fever?

Accepted Answer

It enhances phagocytosis, interferon activity, and tissue repair, aiding in recovery.

Question 11

Which of the following best describes the three phases of inflammation?

Accepted Answer

Vascular changes, leukocyte recruitment, resolution

Question 12

A scientist blocks the action of chemokines in a mouse model. Which of the following immune processes would be most directly affected?

Accepted Answer

Recruitment of white blood cells to sites of infection

Question 13

Which of the following is a correct sequence of events in the activation of the complement system via the classical pathway?

Accepted Answer

Antibody binds antigen $$\rightarrow$$ complement proteins activated $$\rightarrow$$ opsonization/cytolysis/inflammation

Question 14

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

Accepted Answer

It consists of tightly packed epithelial cells that prevent pathogen entry.

Question 15

A patient with a genetic deficiency in NK (natural killer) cells would be most susceptible to which of the following?

Accepted Answer

Viral infections and certain cancers, due to impaired innate immune surveillance

Question 16

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

Accepted Answer

They act as antigen-presenting cells, bridging innate and adaptive immunity.

Question 17

A patient with a severe burn loses a large area of skin. Which aspect of their immune defense is most compromised?

Accepted Answer

Physical barrier

Question 18

Which of the following is a function of tumor necrosis factors (TNFs) in innate immunity?

Accepted Answer

They regulate inflammatory responses and can induce cell death.

Question 19

A patient is exposed to a pathogen for the first time. Which line of defense will respond first, and what is a key feature of this response?

Accepted Answer

First-line defense; immediate, non-specific barrier action

Question 20

A laboratory test shows increased levels of lactoferrin in a patient's secretions. What is the likely effect of this increase?

Accepted Answer

Decreased availability of iron for pathogens, limiting their growth

Innate Immunity: The First Lines of Host Defense

Study Guide - Practice Questions

Study Guide - Flashcards