Question 1

Which of the following best describes the role of keratin in the skin as a surface barrier?

Accepted Answer

Keratin is a protein that is resistant to weak acids, bases, and bacterial enzymes, providing a physical barrier to most microbes.

Question 2

A patient with a genetic defect in mucin production would be most susceptible to which of the following?

Accepted Answer

Increased risk of infections in the digestive and respiratory tracts due to impaired trapping of microbes.

Question 3

Which of the following is NOT a function of inflammation?

Accepted Answer

Directly produces antibodies to neutralize pathogens.

Question 4

During the process of phagocytosis, what is the correct sequence of events after a phagocyte binds to a pathogen?

Accepted Answer

The phagocyte engulfs the pathogen, forms a phagosome, which then fuses with a lysosome to form a phagolysosome for digestion.

Question 5

Which of the following best explains why fever can be beneficial during an infection?

Accepted Answer

Fever increases the metabolic rate, enhancing tissue repair and T lymphocyte production.

Question 6

A patient receives a vaccine containing inactivated viral particles. Which type of immunity is being established?

Accepted Answer

Artificially acquired active immunity

Question 7

Which of the following statements about antigens is correct?

Accepted Answer

Antigens are substances that can provoke an immune response and are usually foreign to the body.

Question 8

A newborn receives antibodies from its mother through breast milk. This is an example of:

Accepted Answer

Naturally acquired passive immunity

Question 9

Which immunoglobulin class is most abundant in plasma and can cross the placental barrier to provide passive immunity to the fetus?

Accepted Answer

IgG

Question 10

A patient is unable to produce class II MHC proteins. Which of the following immune functions would be most directly impaired?

Accepted Answer

Activation of helper T cells by antigen-presenting cells

Question 11

Which of the following best describes the process of opsonization?

Accepted Answer

Antibodies or complement proteins coat pathogens, enhancing their recognition and ingestion by phagocytes.

Question 12

Which of the following is a correct statement about the difference between humoral and cellular immunity?

Accepted Answer

Humoral immunity targets extracellular pathogens with antibodies, while cellular immunity targets infected or abnormal cells using T lymphocytes.

Question 13

A patient with a deficiency in helper T cells would likely experience which of the following?

Accepted Answer

Impaired activation of both B cells and cytotoxic T cells, leading to weakened humoral and cellular immune responses.

Question 14

Which of the following equations best represents the relationship between antibody concentration ($$[Ab]$$), rate of antibody production ($$r$$), and time ($$t) $$during the primary immune response, assuming a constant rate of production and no degradation?

Accepted Answer

$$[Ab] = r 	imes t$$

Question 15

Which of the following best explains why tissue transplants (allografts) require immunosuppressive therapy?

Accepted Answer

To prevent the recipient's immune system from attacking the transplanted tissue due to recognition of foreign MHC antigens.

Question 16

A patient is exposed to a bacterial pathogen for the first time. Which of the following best describes the expected timeline and features of the primary immune response?

Accepted Answer

There is a lag period of 3-6 days before antibody production, with peak levels at about 10 days.

Question 17

Which of the following best describes the function of regulatory T cells (Treg)?

Accepted Answer

They dampen the immune response by direct contact or by secreting inhibitory cytokines, helping prevent autoimmune reactions.

Question 18

Which of the following is a correct match between a cell type and its primary function in the immune system?

Accepted Answer

Dendritic cell: Most effective antigen-presenting cell, captures antigens and presents them to T cells in lymph nodes.

Question 19

Which of the following best explains the process of clonal selection in B lymphocytes?

Accepted Answer

A B cell is activated by binding to its specific antigen, then proliferates and differentiates into plasma cells and memory cells.

Chapter 21: The Immune System – Innate and Adaptive Body Defenses

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