Question 1

Which of the following best describes the role of the stratum corneum in the first line of host defense?

Accepted Answer

It acts as a tough, waterproof barrier that prevents microbial invasion.

Question 2

A patient with severe burns is at increased risk for infection primarily because:

Accepted Answer

They have lost the physical barrier provided by the skin, compromising the first line of defense.

Question 3

Which of the following is NOT a function of the lymphatic system?

Accepted Answer

Producing red blood cells for oxygen transport.

Question 4

Which statement correctly distinguishes histiocytes from other macrophages?

Accepted Answer

Histiocytes are tissue-resident macrophages that remain in a specific tissue during their lifespan.

Question 5

Which of the following is a pro-inflammatory cytokine?

Accepted Answer

Interleukin-1 (IL-1)

Question 6

Which process involves the migration of white blood cells out of blood vessels into tissues?

Accepted Answer

Diapedesis

Question 7

Which of the following best explains the mechanism by which fever helps defend the body?

Accepted Answer

Fever inhibits multiplication of temperature-sensitive microorganisms and increases immune reactions.

Question 8

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

Accepted Answer

Chemotaxis → Ingestion → Phagolysosome formation → Destruction → Excretion

Question 9

Which of the following is a function of the complement system?

Accepted Answer

It forms membrane attack complexes that lyse offending cells.

Question 10

Which of the following is a characteristic of interferons?

Accepted Answer

They induce the production of proteins that inhibit viral multiplication.

Question 11

A patient is found to have a high neutrophil count in their blood. What is the most likely cause?

Accepted Answer

A bacterial infection

Question 12

Which of the following is NOT a component of the first line of defense?

Accepted Answer

Phagocytosis

Question 13

Which body system does NOT participate in the first line of defense?

Accepted Answer

Nervous system

Question 14

Which of the following is a correct statement about the classical complement pathway?

Accepted Answer

It is initiated by binding to antibodies that are already bound to microbes.

Question 15

Which of the following is a function of normal microbiota in the first line of defense?

Accepted Answer

They compete for nutrients and alter local pH to inhibit pathogen growth.

Question 16

Which of the following is a correct overview sentence about the complement system?

Accepted Answer

The complement system is a cascade of blood proteins that destroy bacteria and viruses by forming membrane attack complexes.

Question 17

Which of the following is a correct overview sentence about interferon?

Accepted Answer

Interferon is a host-derived protein that induces antiviral states in cells by inhibiting viral replication and modulating immune responses.

Question 18

Which of the following is a correct description of pathogen-associated molecular patterns (PAMPs)?

Accepted Answer

They are molecules shared by many microbes but not present in mammals, serving as 'red flags' for innate immunity.

Question 19

Which of the following is a correct statement about the movement of lymph in the lymphatic system?

Accepted Answer

Lymph moves only through the contraction of skeletal muscles.

Chapter 12: Host Defenses – Overview and Innate Defenses

Study Guide - Practice Questions