Question 1

Refer to the first image (disease progression curve). Which stage of infectious disease is highlighted in orange, and what is the main characteristic of this stage?

Accepted Answer

Acute phase; the disease reaches its peak severity and symptoms are most pronounced.

Question 2

The second image shows three overlapping circles representing the epidemiological triangle. What do the three circles represent?

Accepted Answer

Host, etiological agent, and environment

Question 3

In the third image, several structures are shown on the surface of a bacterium. Which structure is primarily responsible for immune system evasion by preventing phagocytosis?

Accepted Answer

Capsule

Question 4

The fourth image illustrates various portals of entry for pathogens. Which portal is most commonly associated with respiratory infections such as influenza and COVID-19?

Accepted Answer

Respiratory mucosa

Question 5

The fifth image shows portals of exit for pathogens. Which portal is most relevant for the transmission of urinary tract infections (UTIs)?

Accepted Answer

Urogenital

Question 6

In the sixth image, which of the following is NOT a step in the five-step process of infection for a successful pathogen?

Accepted Answer

Directly causing cancer in the host

Question 7

The seventh image summarizes the three lines of immune defense. Which line of defense is responsible for the production of antibodies?

Accepted Answer

Third-line (adaptive) defenses

Question 8

The eighth image highlights several first-line defenses. Which of the following is an example of a chemical barrier?

Accepted Answer

Lysozyme in tears and saliva

Question 9

The ninth image shows different types of leukocytes. Which cell type is highly phagocytic and is the first to arrive at the site of infection?

Accepted Answer

Neutrophils

Question 10

The tenth image outlines the phases of inflammation. Which phase is characterized by increased blood flow and vessel permeability due to vasoactive molecules?

Accepted Answer

Vascular changes

Question 11

The eleventh image shows leukocyte recruitment. What is the process called when leukocytes squeeze out of capillaries to enter inflamed tissue?

Accepted Answer

Diapedesis

Question 12

The twelfth image depicts the resolution phase of inflammation. What is the main event that occurs during this phase?

Accepted Answer

Inflammation signals decrease and tissue repair is initiated

Question 13

Which of the following best describes the role of cytokines in the immune response, as illustrated in the images?

Accepted Answer

They are signaling proteins that coordinate immune actions and recruit leukocytes.

Question 14

Based on the visual summary, which of the following is a function of complement proteins in the immune system?

Accepted Answer

Form membrane attack complexes to lyse cells

Question 15

Which of the following is a correct pairing of a hypersensitivity type and an example, as shown in the visual summary?

Accepted Answer

Type II hypersensitivity – blood transfusion reaction

Question 16

Which of the following best describes the difference between innate and adaptive immunity?

Accepted Answer

Innate immunity is nonspecific and immediate; adaptive immunity is specific and has memory.

Question 17

Which of the following is an example of artificially acquired passive immunity?

Accepted Answer

Antivenom administration

Question 18

Which of the following is a key feature of exotoxins, as compared to endotoxins?

Accepted Answer

They are proteins that can be neutralized by antibodies.

Question 19

Which of the following is a mechanism by which pathogens evade the host immune system?

Accepted Answer

Antigenic variation

Question 20

Which of the following best describes the function of antimicrobial peptides (AMPs) in innate immunity?

Accepted Answer

They directly target and destroy pathogens by disrupting membranes.

Principles of Infectious Disease, Epidemiology, and Immunity

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