Question 1

Innate immunity
A) provides increased susceptibility to disease.
B) involves T cells and B cells.
C) is slower than adaptive immunity in responding to pathogens.
D) is nonspecific and present at birth.
E) involves a memory component.

Accepted Answer

Innate immunity is the body's first line of defense, present at birth, and acts nonspecifically against pathogens. It does not involve T cells and B cells, which are part of adaptive immunity, nor does it have a memory component.

Question 2

TLRs attach to all of the following EXCEPT
A) LPS.
B) peptidoglycan.
C) PAMPs.
D) AMPs.
E) flagellin.

Accepted Answer

TLRs (Toll-like receptors) recognize PAMPs (pathogen-associated molecular patterns) such as LPS, peptidoglycan, and flagellin. AMPs (antimicrobial peptides) are not recognized by TLRs.

Question 3

Which of the following statements is TRUE?
A) Alpha interferon acts against specific viruses.
B) Beta interferon attacks invading viruses.
C) Gamma interferon causes bactericidal activity by macrophages.
D) All three types of interferons have the same effect on the body.
E) Alpha interferon promotes phagocytosis.

Accepted Answer

Gamma interferon is known to activate macrophages, enhancing their ability to kill bacteria and other pathogens.

Question 4

Margination refers to
A) adherence of phagocytes to the lining of blood vessels.
B) the adherence of phagocytes to microorganisms.
C) the chemotactic response of phagocytes.
D) dilation of blood vessels.
E) the movement of phagocytes through walls of blood vessels.

Accepted Answer

Margination is the process where phagocytes adhere to the endothelial lining of blood vessels during inflammation, preparing to exit the bloodstream and enter tissue.

Question 5

The antimicrobial effects of AMPs include all of the following EXCEPT
A) lysis of bacterial cells.
B) inhibition of cell wall synthesis.
C) pore formation in bacterial membranes.
D) inhibition of phagocytosis.
E) destruction of nucleic acids.

Accepted Answer

Antimicrobial peptides (AMPs) do not inhibit phagocytosis; they primarily target microbial cells directly through mechanisms like lysis, pore formation, and destruction of nucleic acids.

Question 6

The function of the ʺciliary escalatorʺ is to
A) remove microorganisms from the lower respiratory tract.
B) propel inhaled dust and microorganisms toward the mouth, away from the lower respiratory tract.
C) trap inhaled dust and microorganisms in mucus and propel it away from the lower respiratory tract.
D) remove microorganisms from the gastrointestinal tract.
E) trap microorganisms in mucus in the upper respiratory tract.

Accepted Answer

The ciliary escalator traps inhaled dust and microorganisms in mucus and propels it away from the lower respiratory tract, helping to keep the airways clear.

Question 7

All of the following increase blood vessel permeability EXCEPT
A) prostaglandins.
B) histamine.
C) kinins.
D) lysozymes.
E) leukotrienes.

Accepted Answer

Lysozymes are enzymes that break down bacterial cell walls and do not play a role in increasing blood vessel permeability.

Question 8

The swelling associated with inflammation decreases when the fluid
A) is excreted in urine.
B) is transported into macrophages.
C) goes into lymph capillaries.
D) returns to the blood.
E) is lost as perspiration.

Accepted Answer

The swelling decreases when excess fluid is drained away by the lymphatic system, entering lymph capillaries and eventually returning to the bloodstream.

Question 9

Normal microbiota provide protection from infection in each of the following ways EXCEPT
A) they make the chemical environment unsuitable for nonresident bacteria.
B) they produce antibacterial chemicals.
C) they produce lysozyme.
D) they change the pH of the environment.
E) they compete with pathogens for nutrients.

Accepted Answer

Normal microbiota do not produce lysozyme; lysozyme is an enzyme found in bodily secretions like tears and saliva that breaks down bacterial cell walls.

Question 10

A child falls and suffers a deep cut on her leg. The cut went through her skin and she is bleeding. Which of the following defense mechanisms will participate in eliminating contaminating microbes?
A) normal skin flora
B) lysozyme
C) acidic skin secretions
D) mucociliary escalator
E) phagocytosis in the inflammatory response

Accepted Answer

Phagocytosis in the inflammatory response is a defense mechanism that actively participates in eliminating microbes that enter through a cut, as phagocytes engulf and destroy pathogens at the site of injury.

Question 11

Each of the following provides protection from phagocytic digestion EXCEPT
A) M protein.
B) leukocidins.
C) formation of phagolysosomes.
D) capsules.
E) biofilms.

Accepted Answer

Formation of phagolysosomes is a process that occurs within phagocytes to digest engulfed pathogens, not a mechanism for protection against phagocytic digestion.

Question 12

Which of the following exhibits the highest phagocytic activity?
A) neutrophils
B) erythrocytes
C) macrophages
D) eosinophils
E) basophils

Accepted Answer

Macrophages exhibit the highest phagocytic activity as they are specialized cells designed to engulf and digest cellular debris and pathogens.

Question 13

A differential cell count is used to determine each of the following EXCEPT
A) the numbers of each type of white blood cell.
B) leukopenia.
C) leukocytosis.
D) the number of red blood cells.
E) the total number of white blood cells.

Accepted Answer

A differential cell count is used to determine the numbers of each type of white blood cell, leukopenia, leukocytosis, and the total number of white blood cells, but not the number of red blood cells.

Question 14

Phagocytes utilize all of the following to optimize interaction with (getting to and getting hold of) microorganisms EXCEPT
A) chemotaxis.
B) complement.
C) trapping a bacterium against a rough surface.
D) opsonization.
E) lysozyme.

Accepted Answer

Lysozyme is an enzyme that breaks down bacterial cell walls, not a mechanism for optimizing interaction with microorganisms.

Question 15

Which of the following statements about fixed macrophages is FALSE?
A) They are mature monocytes.
B) They gather at sites of infection.
C) They are cells of the mononuclear phagocytic system.
D) They develop from neutrophils.
E) They are found in certain tissues and organs.

Accepted Answer

Fixed macrophages do not develop from neutrophils; they develop from monocytes. Neutrophils are a different type of white blood cell.

Question 16

All of the following protect the skin and mucous membranes from infection EXCEPT
A) saliva.
B) tears.
C) multiple layers of cells.
D) HCl.
E) the ʺciliary escalator.ʺ

Accepted Answer

Hydrochloric acid (HCl) is found in the stomach and aids in digestion, not directly in protecting skin and mucous membranes from infection.

Question 17

The complement protein cascade is the same for the classical pathway, alternative pathway, and lectin pathway after the point in the cascade where the activation of takes place.
A) C2
B) C6
C) C1
D) C3
E) C5

Accepted Answer

The complement protein cascade converges at the activation of C3, which is common to the classical, alternative, and lectin pathways.

Question 18

Which of the following is found normally in serum?
A) leukocytosis-promoting factor
B) histamine
C) complement
D) TLRs
E) interferon

Accepted Answer

Complement is a group of proteins normally present in serum that play a role in immune responses.

Question 19

Each of the following is an effect of complement activation EXCEPT
A) increased blood vessel permeability.
B) opsonization.
C) interference with viral replication.
D) bacterial cell lysis.
E) increased phagocytic activity.

Accepted Answer

Complement activation does not directly interfere with viral replication; it primarily targets bacteria and other pathogens through mechanisms like opsonization, cell lysis, and enhancing phagocytosis.

Question 20

Which of the following is an effect of opsonization?
A) increased diapedesis of phagocytes
B) increased margination of phagocytes
C) increased adherence of phagocytes to microorganisms
D) cytolysis
E) inflammation

Accepted Answer

Opsonization enhances the adherence of phagocytes to microorganisms by marking them for phagocytosis, making it easier for the immune cells to recognize and engulf them.

Quiz 16: Innate Immunity: Nonspecific Defenses of the Host

Innate immunity

TLRs attach to all of the following EXCEPT

Which of the following statements is TRUE?

Margination refers to

The antimicrobial effects of AMPs include all of the following EXCEPT

The function of the ʺciliary escalatorʺ is to

All of the following increase blood vessel permeability EXCEPT

The swelling associated with inflammation decreases when the fluid

Normal microbiota provide protection from infection in each of the following ways EXCEPT

A child falls and suffers a deep cut on her leg. The cut went through her skin and she is bleeding. Which of the following defense mechanisms will participate in eliminating contaminating microbes?

Each of the following provides protection from phagocytic digestion EXCEPT

Which of the following exhibits the highest phagocytic activity?

A differential cell count is used to determine each of the following EXCEPT

Phagocytes utilize all of the following to optimize interaction with (getting to and getting hold of) microorganisms EXCEPT

Which of the following statements about fixed macrophages is FALSE?

All of the following protect the skin and mucous membranes from infection EXCEPT

The complement protein cascade is the same for the classical pathway, alternative pathway, and lectin pathway after the point in the cascade where the activation of takes place.

Which of the following is found normally in serum?

Each of the following is an effect of complement activation EXCEPT

Which of the following is an effect of opsonization?