Question 1

Macrophages arise from which of the following?
A) monocytes
B) eosinophils
C) basophils
D) neutrophils
E) lymphocytes

Accepted Answer

Macrophages arise from monocytes, which are produced in the bone marrow and are a type of white blood cell.

Question 2

A chill is a sign that
A) blood vessels are dilating.
B) body temperature is falling.
C) body temperature is not changing.
D) the metabolic rate is decreasing.
E) body temperature is rising.

Accepted Answer

A chill is a physiological response to a rising body temperature, often due to the body generating heat to fight off infection or maintain homeostasis.

Question 3

Which of the following statements about the classical pathway of complement activation is FALSE?
A) Cleaved fragments of some of the proteins act to increase inflammation.
B) The C1 protein complex is initiated by antigen-antibody complexes.
C) C3b causes opsonization.
D) C3 is not involved in the classical pathway.
E) C1 is the first protein activated in the classical pathway.

Accepted Answer

C3 is actually an important part of the classical pathway, as it is cleaved into C3a and C3b by the C1 complex and C4b2a complex. C3b then contributes to opsonization and the formation of the membrane attack complex.

Question 4

Several inherited deficiencies in the complement system occur in humans. Which of the following would be the MOST severe?
A) deficiency of C3
B) deficiency of C5
C) deficiency of C6
D) deficiency of C7
E) deficiency of C8

Accepted Answer

Deficiency of C3 is the most severe as it is the central component of the complement system, necessary for the activation of both the classical and alternative pathways. Deficiencies in C5-C9 result in an increased susceptibility to certain infections but are generally less severe than C3 deficiency.

Question 5

The lectin pathway for complement action is initiated by
A) mannose on host membranes.
B) gram- negative cell walls.
C) lectins of the microbe.
D) gram- positive cell walls.
E) mannose on the surface of microbes.

Accepted Answer

The lectin pathway for complement action is initiated by the presence of mannose on the surface of microbes, which is recognized by specific lectins. This leads to the activation of the complement system and subsequent destruction of the microbe. Therefore, choice E is the correct answer. Choices A, B, C, and D are not correct as they do not initiate the lectin pathway.

Question 6

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

Accepted Answer

Normal microbiota do not produce lysozyme. Lysozyme is an antibacterial enzyme found in tears, saliva, and mucus that helps protect against bacterial infections. However, normal microbiota do compete with pathogens for nutrients, produce antibacterial chemicals, make the environment unsuitable for nonresident bacteria, and can change the pH of the environment.

Question 7

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

Accepted Answer

Lysozymes are enzymes that break down bacterial cell walls and do not increase blood vessel permeability. The other options, leukotrienes, histamine, kinins, and prostaglandins, all increase blood vessel permeability.

Question 8

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

Accepted Answer

The lymphatic system helps to remove excess fluid and waste products from the tissues, including the fluid associated with inflammation. This fluid is transported through lymph capillaries and eventually returned to the blood.

Question 9

After ingesting a pathogen, lysosomal enzymes produce all of the following EXCEPT A) HOCl. B) OH·. C) complement. D) O₂^-. E) H₂O₂.

Accepted Answer

Lysosomal enzymes do not produce complement, as complement is part of the innate immune system and is produced by other cell types, such as macrophages and hepatocytes. The other choices are all products of lysosomal enzymes.

Question 10

All of the following are part of the mechanism of action of alpha and beta interferons EXCEPT
A) they disrupt stages of viral multiplication.
B) they initiate transcription.
C) they initiate manufacture of antiviral proteins.
D) they are effective for long periods.
E) they bind to the surface of uninfected cells.

Accepted Answer

Alpha and beta interferons are not effective for long periods. They have a short half-life in the body, usually a few hours to a day, and require continuous production to be effective against viral infection.

Question 11

Innate immunity includes all of the following EXCEPT
A) activation of complement.
B) phagocytosis.
C) inflammation.
D) production of interferon.
E) production of antibody.

Accepted Answer

Production of antibody is not part of innate immunity, it is a function of adaptive immunity.

Question 12

All of the following are components of the inflammatory process EXCEPT
A) diapedesis.
B) chemotaxis.
C) release of histamines and prostaglandins.
D) antibody synthesis.
E) dilation of blood vessels.

Accepted Answer

The answer of All of the following are components of...

Question 13

All of the following pertain to fever EXCEPT that it
A) stimulates T lymphocyte activity.
B) intensifies the effect of antiviral interferons.
C) is caused by interleukin- 1 and TNF- alpha coming into contact with the hypothalamus.
D) can be initiated by specific types of pathogens.
E) accelerates microbial growth by increasing iron absorption from the digestive tract.

Accepted Answer

Fever actually decreases microbial growth as it raises the body temperature above the optimal range for many pathogenic microbes to thrive. In addition, fever also causes the liver and spleen to sequester iron, making it less available for microbes to use. Therefore, it does not accelerate microbial growth by increasing iron absorption from the digestive tract.

Question 14

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

Accepted Answer

All of the other answer choices - chemotaxis, complement, opsonization, and trapping a bacterium against a rough surface - are mechanisms utilized by phagocytes to optimize their interaction with microorganisms. However, lysozyme is not used by phagocytes to interact with microorganisms, but rather to break down bacterial cell walls once they have been engulfed.

Question 15

Which non- specific defense mechanism is mismatched with its associated body structure or body fluid?
A) cerumen and sebum - ear
B) lysozyme - tears and saliva
C) keratin and tightly packed cells - skin
D) mucociliary escalator - intestines
E) very acidic pH- stomach

Accepted Answer

The mucociliary escalator is associated with the respiratory system, not the intestines.

Question 16

The complement protein cascade is the same for the classical pathway, alternative pathway, and lectin pathway beginning with the activation of
A) C1.
B) C2.
C) C3.
D) C5.
E) C6.

Accepted Answer

The complement cascade begins with the activation of C3 in all three pathways.

Question 17

Lysozyme and the antibiotic penicillin have similar mechanisms of action in that they both cause damage to the bacterial
A) DNA.
B) cell membrane.
C) ribosomes.
D) capsule.
E) cell wall.

Accepted Answer

Lysozyme and penicillin both target the bacterial cell wall, causing damage and eventually leading to bacterial death. Lysozyme breaks down the bonds between the sugar molecules in the cell wall, while penicillin interferes with the formation of the cell wall, ultimately leading to lysis of the bacterium.

Question 18

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) acidic skin secretions
C) lysozyme
D) mucociliary escalator
E) phagocytosis in the inflammatory response

Accepted Answer

Phagocytosis in the inflammatory response is a defense mechanism that will participate in eliminating contaminating microbes when the skin barrier is breached, as it involves immune cells engulfing and destroying pathogens.

Question 19

All of the following are iron- binding proteins found in humans EXCEPT
A) ferritin.
B) transferrin.
C) siderophorin.
D) hemoglobin.
E) lactoferrin.

Accepted Answer

Siderophorin is not an iron-binding protein found in humans, but is a type of small molecule synthesized by microorganisms to scavenge iron. The other options are all iron-binding proteins found in humans.

Question 20

The classical pathway for complement activation is initiated by
A) factors released from damaged tissues.
B) antigen-antibody reactions.
C) factors released from phagocytes.
D) lipid- carbohydrate complexes and C3.
E) C5-C9.

Accepted Answer

The classical pathway for complement activation is initiated by antigen-antibody reactions, specifically IgG or IgM binding to an antigen. This triggers a complex cascade of enzymatic reactions that ultimately results in the formation of the membrane attack complex (MAC) to lyse foreign cells.

Quiz 16: Innate Immunity: Nonspecific Defenses of the Host

Macrophages arise from which of the following?

A chill is a sign that

Which of the following statements about the classical pathway of complement activation is FALSE?

Several inherited deficiencies in the complement system occur in humans. Which of the following would be the MOST severe?

The lectin pathway for complement action is initiated by

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

All of the following increase blood vessel permeability EXCEPT

The swelling associated with inflammation decreases when the fluid

After ingesting a pathogen, lysosomal enzymes produce all of the following EXCEPT

All of the following are part of the mechanism of action of alpha and beta interferons EXCEPT

Innate immunity includes all of the following EXCEPT

All of the following are components of the inflammatory process EXCEPT

All of the following pertain to fever EXCEPT that it

Phagocytes utilize all of the following to optimize interaction with microorganisms EXCEPT

Which non- specific defense mechanism is mismatched with its associated body structure or body fluid?

The complement protein cascade is the same for the classical pathway, alternative pathway, and lectin pathway beginning with the activation of

Lysozyme and the antibiotic penicillin have similar mechanisms of action in that they both cause damage to the bacterial

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?

All of the following are iron- binding proteins found in humans EXCEPT

The classical pathway for complement activation is initiated by