Question 1

Which of the following best describes the role of keratin in the first line of defense against pathogens?

Accepted Answer

Keratin forms a physical barrier that is resistant to weak acids, bases, bacterial enzymes, and toxins.

Question 2

A patient presents with a cut that has become red, swollen, and painful. Which sequence of events best explains the acute inflammatory response?

Accepted Answer

Release of inflammatory chemicals, vasodilation and increased vascular permeability, phagocyte mobilization.

Question 3

Which of the following is NOT a function of the innate (nonspecific) defense system?

Accepted Answer

Producing antibodies that specifically target pathogens.

Question 4

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

Accepted Answer

Phagocyte forms pseudopods, phagosome fuses with lysosome, phagolysosome is acidified, indigestible material is exocytosed.

Question 5

Which chemical released during inflammation is primarily responsible for vasodilation and increased permeability of local capillaries?

Accepted Answer

Histamine

Question 6

What is the main benefit of moderate fever during an infection?

Accepted Answer

It increases metabolic rate, which enhances repair processes and causes liver and spleen to sequester iron and zinc.

Question 7

Which of the following best describes opsonization?

Accepted Answer

The process by which antibodies or complement proteins coat pathogens, enhancing phagocytosis.

Question 8

A virus-infected cell releases interferons. What is the primary effect of these interferons on neighboring cells?

Accepted Answer

They stimulate neighboring cells to produce proteins that block viral reproduction and degrade viral RNA.

Question 9

Which pathway of complement activation involves antibodies binding to invading organisms and then binding to complement components?

Accepted Answer

Classical pathway

Question 10

What is the function of the membrane attack complex (MAC) formed during complement activation?

Accepted Answer

MAC forms pores in the target cell membrane, causing lysis by allowing water to enter and cell contents to leave.

Question 11

Which of the following is a cardinal sign of acute inflammation?

Accepted Answer

Redness

Question 12

Which cell type is most abundant among phagocytes and becomes phagocytic upon exposure to infectious material?

Accepted Answer

Neutrophils

Question 13

What is the primary mechanism by which natural killer (NK) cells destroy cancer and virus-infected cells?

Accepted Answer

Inducing apoptosis in target cells

Question 14

Which of the following is a benefit of edema during inflammation?

Accepted Answer

Edema sweeps foreign material into lymphatic vessels for processing in lymph nodes and delivers clotting proteins to the area.

Question 15

Which step in phagocyte mobilization involves neutrophils clinging to the capillary wall in the inflamed area?

Accepted Answer

Margination

Question 16

Which antimicrobial protein family is used clinically to treat disorders such as hepatitis C, genital warts, and multiple sclerosis?

Accepted Answer

Interferons

Question 17

Which of the following is a mechanism by which helper T cells assist macrophages in killing pathogens resistant to lysosomal enzymes?

Accepted Answer

Triggering respiratory burst, releasing cell-killing free radicals and oxidizing chemicals

Question 18

Which of the following is NOT a protective mechanism of intact mucous membranes?

Accepted Answer

Keratinization of the membrane

Question 19

Which of the following best describes the role of Toll-like receptors (TLRs) in the immune system?

Accepted Answer

TLRs recognize and bind tightly to structures on microbes, triggering immune responses.

Question 20

Which complement protein is central to all three activation pathways and splits into two active pieces to initiate the terminal pathway?

Accepted Answer

C3

The Immune System: Innate and Adaptive Body Defenses

Study Guide - Practice Questions