Question 1

Which of the following is an example of a physical barrier in the body's defense system?

Accepted Answer

Skin preventing entry of pathogens

Question 2

Which chemical barrier is responsible for killing many pathogens in the stomach?

Accepted Answer

Stomach acid

Question 3

A patient has a genetic disorder that prevents the production of mucus in the stomach. Which consequence is most likely?

Accepted Answer

Higher likelihood of localized stomach infections

Question 4

Which of the following best describes the role of phagocytes in the innate immune system?

Accepted Answer

They engulf and digest pathogens and damaged host cells.

Question 5

Which statement about the adaptive immune system is correct?

Accepted Answer

It targets specific pathogens using B and T cells.

Question 6

If a person is exposed to a pathogen for the second time, which cells are primarily responsible for a faster immune response?

Accepted Answer

Memory cells

Question 7

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

Accepted Answer

Producing antibodies specific to pathogens

Question 8

A person has a deficiency in Helper T cells. Which process would be most affected?

Accepted Answer

Triggering production of B cells and killer T cells

Question 9

Which equation best represents the relationship between the number of pathogens ($$P) $$and the effectiveness of the immune response ($$E$$), assuming $$E$$ increases as $$P$$ increases up to a threshold $$T$$?

Accepted Answer

$$E = \frac{P}{T}$$ for $$P \u003c T$$, $$E = 1$$ for $$P \geq T$$

Question 10

Which of the following statements about antigens is correct?

Accepted Answer

Antigens are substances that trigger an immune response when identified as foreign.

Question 11

A patient is infected with a virus that mutates rapidly, changing its surface antigens. Which branch of the immune system is most challenged by this?

Accepted Answer

Adaptive immune system

Question 12

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

Accepted Answer

Helper T cells trigger B cell production, B cells produce antibodies, Memory cells are formed

Question 13

Which of the following is a plausible consequence if the mucus lining in the respiratory tract is damaged?

Accepted Answer

Increased risk of airborne infections

Question 14

Which cell type is responsible for directly attacking and destroying infected cells in the adaptive immune system?

Accepted Answer

Killer T cells

Question 15

Which of the following is a correct statement about inflammation?

Accepted Answer

Inflammation can cause swelling, pain, and heat as part of the immune response.

Question 16

If $$N is $$the number of natural killer cells and $$I is $$the number of infected cells, which formula best represents the rate $$R at $$which infected cells are destroyed, assuming each natural killer cell destroys one infected cell per unit time?

Accepted Answer

$$R = N$$

Question 17

Which of the following is NOT a role of B cells in the adaptive immune system?

Accepted Answer

Engulfing pathogens directly

Question 18

A person recovers from an infection and is exposed to the same pathogen months later. Which process allows for a faster and stronger immune response?

Accepted Answer

Activation of memory cells

Question 19

Which of the following statements is incorrect about the function of the immune system?

Accepted Answer

Question 20

Which of the following best explains why the adaptive immune system is slower to respond than the innate immune system?

Accepted Answer

It must first identify specific antigens and produce targeted cells and antibodies.

Body's Defense System: Physical, Chemical, and Immune Barriers

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