Question 1

Which of the following best describes the primary function of surface barriers in the immune system?

Accepted Answer

They act as the first line of defense by physically blocking pathogen entry.

Question 2

Which immune cells are primarily responsible for humoral immunity, and what is their main target?

Accepted Answer

B cells; extracellular pathogens

Question 3

What is the main difference between innate and adaptive defenses?

Accepted Answer

Innate defenses provide immediate, nonspecific protection; adaptive defenses are slower but specific.

Question 4

Which of the following is NOT considered an internal innate defense?

Accepted Answer

Antibody production

Question 5

A patient receives a vaccine and later develops immunity to the disease. This is an example of:

Accepted Answer

Active artificial immunity

Question 6

Which type of T cell is primarily responsible for directly killing infected or cancerous cells?

Accepted Answer

Cytotoxic T cell

Question 7

What is the role of helper T cells (TH cells) in the activation of cytotoxic T cells (TC cells)?

Accepted Answer

They secrete cytokines that stimulate TC cell proliferation and activation.

Question 8

Which of the following best describes the function of interferons?

Accepted Answer

They signal neighboring cells to produce antiviral proteins.

Question 9

Which of the following is a characteristic of an antigen?

Accepted Answer

It is any substance that can trigger an immune response.

Question 10

What is the main function of memory cells in the adaptive immune system?

Accepted Answer

To provide a faster and stronger response upon subsequent exposures to the same antigen.

Question 11

Which of the following best describes the difference between MHC I and MHC II molecules?

Accepted Answer

MHC I presents endogenous antigens to cytotoxic T cells; MHC II presents exogenous antigens to helper T cells.

Question 12

Which of the following is a correct sequence of events during inflammation?

Accepted Answer

Vasodilation, increased permeability, phagocyte arrival, tissue repair

Question 13

Which of the following best explains why autoimmune diseases occur?

Accepted Answer

The immune system fails to recognize self-antigens and attacks the body's own tissues.

Question 14

A patient is given an injection of antibodies after exposure to a toxin. This is an example of:

Accepted Answer

Passive artificial immunity

Question 15

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

Accepted Answer

Enhancing phagocytosis and lysing pathogens

Question 16

Which of the following best describes the effect of aging on the immune system?

Accepted Answer

Immune function declines, increasing susceptibility to infections and cancer.

Question 17

Which of the following is the first phagocyte to arrive at the site of inflammation?

Accepted Answer

Neutrophil

Question 18

After clonal selection, most B cell clones become:

Accepted Answer

Plasma cells that secrete antibodies

Question 19

Which of the following best describes AIDS?

Accepted Answer

A disease caused by the human immunodeficiency virus (HIV), which destroys helper T cells

Question 20

Which of the following is a key function of antibodies?

Accepted Answer

Neutralizing toxins and marking pathogens for destruction

The Immune System: Innate and Adaptive Body Defenses

Study Guide - Practice Questions