Chapter 15 mastering questions

Phagocytic cells associated with the epidermis are called __________.
goblet cells
neutrophils
erythrocytes
dendritic cells

Dendritic cells are phagocytic cells in the epidermis with fingerlike projections that form a network used to intercept invaders.

Erythrocytes, leukocytes, and platelets are formed by a process called __________.
diapedesis
hematopoiesis
margination
phagocytosis

Hematopoiesis is the production of the formed elements of the blood by stem cells in the bone marrow.

Tears contain which of the following antibacterial substances?
sebum
hydrogen peroxide
mucus
lysozyme

lysozyme. In addition to their cleansing action, tears contain lysozyme, an enzyme that breaks down the peptidoglycan in bacterial cell walls.

Which of the following leukocytes is primarily responsible for an immune response against helminths?
neutrophils
basophils
eosinophils
lymphocytes

eosinophils

Why are smokers more likely to have infections with respiratory pathogens?
Respiratory pathogens produce substances that react with tobacco smoke.
Smokers do not produce as much mucus as do nonsmokers.
Poisons in tobacco smoke damage ciliated columnar cells.
Smokers do not produce lysozyme in their mucus.

Poisons in tobacco smoke damage ciliated columnar cells. Tobacco smoke contains substances that damage ciliated cells in the respiratory tract. This makes it more difficult for smokers to clear their lungs of potential pathogens.

A differential white blood cell count that shows elevated levels of eosinophils probably indicates which of the following in the patient?
viral infection
cancer
allergies
bacterial infection

allergies. Although their exact function in allergies is disputed, eosinophils are usually present in large numbers during allergic reactions.

Why is the alternative pathway of complement useful in the early stages of an infection?
It is faster than the other complement pathways.
It does not result in a MAC.
It can recognize pathogens specifically.
It does not rely on activation by antibodies.

Because it does not rely on activation by antibodies, the alternative pathway is useful in the early stages of infection, when antibody production has not reached its maximal levels yet.

Which of the following is a way that antimicrobial peptides are used in the second line of defense?
They punch holes in the cytoplasmic membranes of pathogens.
They serve as chemotactic factors for leukocytes.
They interrupt internal signaling in cells.
They are found on the skin and mucous membranes.

By serving as chemotactic factors for leukocytes, antimicrobial peptides can play a role in such processes as phagocytosis, a component of the second line of defense.

All of the following are ways that neutrophils can directly or indirectly kill cells EXCEPT __________.
by producing nitric oxide
by producing NETs
by forming MACs
by producing superoxide radical

MACs, or membrane attack complexes, are used in the complement system.

Due to the action of tears, potential pathogens of the eyes and its membranes usually end up where?
the skin
the lungs
the stomach
the bloodstream

Tears (and the microbes collected by them) flow into the nose through a series of canals and ducts; here, they mix with nasal mucus and pass into the pharynx, where they are swallowed.

Which of the following is the third step in phagocytosis?
enzymatic destruction of the microbe
ingestion
adherence
fusion of vesicles with lysosomes

fusion of vesicles with lysosomes

What will happen if an animal raised in an axenic environment is exposed to a pathogenic microbe later in life?
The animal’s immune system will respond normally to the pathogen.
The animal’s second line of defense will respond normally, but the first line of defense will be compromised.
The animal will exhibit a very poor immune response to the pathogen.
The animal’s immune system will produce an excessive response to the pathogen.

The animal will exhibit a very poor immune response to the pathogen. Animals raised in axenic environments have immune systems that respond poorly, if at all, to microbial invaders because they have not been constantly stimulated by the presence of normal microbiota.

What would be the likely outcome if a microbe could prevent the activation of C3 in the complement cascade?
The microbe would be unaffected by complement.
Inflammation would be the only outcome of complement activation if C3 activation is blocked.
The microbe would be killed by the membrane attack complex.
The microbe would be opsonized.

Inflammation would be the only outcome of complement activation if C3 activation is blocked.

Malfunctioning goblet cells would result in which of the following problems?
reduced chemotaxis of neutrophils
death of normal microbiota
increased respiratory infections
abnormally slow phagocytosis

increased respiratory infections. Without the mucus produced by goblet cells, the respiratory tract would be at greater risk of infection by respiratory pathogens.

A human cell that maintains an antiviral state induced by alpha or beta interferons for too long will die because __________.
it cannot engage in glucose metabolism
it cannot make proteins
it cannot repair its cytoplasmic membrane
it cannot move

it cannot make proteins. Even though the antiviral state results in the cessation of protein synthesis in a cell, it is not deleterious to the cell because it normally lasts only a few days.

A microbiologist has isolated a bacterium from the skin and wishes to determine whether it might be a member of the normal microbiota. Which of the following would NOT be evidence for such a conclusion?
The bacterium is resistant to lysozyme.
The bacterium is an acidophile.
The bacterium is extremely salt tolerant.
The bacterium produces a number of virulence factors.

The bacterium produces a number of virulence factors. A member of the normal microbiota of the skin would be expected to be salt and acid tolerant, as well as resistant to the body’s defensive chemicals such as lysozyme.

Which of the complement pathways employs properdin?
Classical pathway
Alternative pathway
Lectin pathway
Alternative and lectin pathways all employ properdin.
Classical, alternative, and lectin pathways all employ properdin.
The classical and alternative pathways both require properdin.

Alternative pathway

In the classical pathway, which of the following directly activates cellular responses?
C3a and C5a
C2aC4b
C4aC2bC3b
C5bC6C7
C3b
C3a, C5a, and C5bC6C7

C3a, C5a, and C5bC6C7

Antibodies from cellular immune responses are used in..
the lectin pathway.
the alternative pathway.
the classical pathway.
both the classical and alternative pathways.

the classical pathway.

Which of the complement pathways was discovered first?
The lectin pathway
The classical pathway
The alternative pathway

The classical pathway

Which of the following are functions of lectins?
They produce factor P (properdin).
They act as opsonins for phagocytosis, they attach to carbohydrates on some bacterial and viral surfaces, and they activate C2 and C4.
They act as opsonins for phagocytosis.
They attach to carbohydrates on some bacterial and viral surfaces.
They can activate C2 and C4.
They produce antibodies.

They act as opsonins for phagocytosis, they attach to carbohydrates on some bacterial and viral surfaces, and they activate C2 and C4.

What cellular macromolecules make up the complement pathway?
Carbohydrates
Proteins
Lipids
Nucleic acids

Proteins

Where are the complement proteins found in the body?
The spleen
The blood serum
The thymus
In every cell
The liver

The blood serum

Based on the animation, which of the following is cleaved by C1?
C5 and C4
C2
C4
C2 and C4
C5

C2 and C4

Based on the animation, which of the following is responsible for cleaving C3?
C1
C5bC6C7
C2aC4b
C4aC2b

C2aC4b

Based on the animation, which of the complement proteins can directly bind to the surface of a bacterial cell?
C2b
C5b
C2a
C3b
C4a

C3b

How does cytolysis occur via the complement pathway?
Formation of the MAC in invading cells, killing them
Stimulation of the inflammatory response
Triggering the release of histamine
Disrupting cell wall of pathogens

Formation of the MAC in invading cells, killing them

Which complement protein is used as an opsonin?
C3b
C5b
C2a
C4a
C7
C3a

C3b

If a person lacked the ability to form C5, what direct result of complement could still occur?
Opsonization
Cytolysis
Chemotaxis

Opsonization

If a person could not form C2, which result of complement would be affected?
Chemotaxis and inflammation
Cytolysis
Cytolysis, chemotaxis, inflammation, and opsonization
Opsonization

Cytolysis, chemotaxis, inflammation, and opsonization

What complement result involves the use of phagocytes?
Cytolysis
Opsonization
Chemotaxis
Chemotaxis and opsonization

Chemotaxis and opsonization

The absence of C5 means that the molecule is not present to be activated. What happens in normal serum when C5 is "activated"?
C5 binds to Factor B.
C5 becomes a protein-digesting enzyme that splits C3 into two fragments, C3a and C3b.
C5 is bound to the membrane-attack complex.
C3b is a part of enzyme that splits C5 into two fragments, C5a and C5b.

C3b is a part of enzyme that splits C5 into two fragments, C5a and C5b.

If a microbe were capable of preventing a phagosome from fusing with a lysosome, which of the following would occur?
The microbe would cause the phagocyte to go through apoptosis.
The microbe would be expelled from the residual body.
The microbe would survive inside the phagocyte.
The microbe would be killed by the lysosome’s enzymes.

The microbe would survive inside the phagocyte.

The events of fever are antagonistic to which of the following processes?
interferon activity
vasodilation
tissue repair
phagocytosis

vasodilation. The vasoconstriction associated with fever can in some ways be antagonistic to the vasodilation that occurs as an integral event in inflammation.

The skin and the mucous membranes are similar in which of the following aspects?
outer layer of dead cells
production of mucus
epithelial cells packed closely together
multiple layers of epidermal cells

epithelial cells packed closely together

Humans have species resistance to feline immunodeficiency virus for which of the following reasons?
Feline immunodeficiency virus is a nonpathogenic virus.
Human cells produce a special type of interferon that protects against feline immunodeficiency virus.
Human cells do not have the chemical receptors required for attachment by feline immunodeficiency virus.
Human phagocytes are extremely effective at eliminating feline immunodeficiency virus from the body.

Human cells do not have the chemical receptors required for attachment by feline immunodeficiency virus.

Basophils, platelets, and _____ are all capable of secreting histamines.
mast cells
monocytes
neutrophils
complement

Mast cells are found in the tissues outside of the blood and release histamine in response to complement.

Which of the following groupings contain things that are all true indicators of inflammation?
redness, heat, edema, pain, fever
redness, heat, edema, pain
blueness, coolness, edema, pain
redness, coolness, numbness, fever

The redness and heat are due to the increased blood flow attributed to vasodilation, and the edema and pain are due to the increased permeability that allows fluids to leak into the surrounding tissues.

Increased permeability of the vessels leads to _____ and pain.
redness
fever
heat
edema

edema. The excess fluid collects in the tissues and leads to edema or swelling, which in turn exerts pressure on the nerves, causing the pain associated with inflammation.

The process of blood clotting leads to the formation of _____ a potent mediator of inflammation.
eukotriene
bradykinin
histamine
prostaglandin

bradykinin

Histamines are released when mast cells are exposed to _____, which are fragments of complement proteins.
bradykinins
platelets
C3 and C5
C3a and C5a

The complement proteins C3a and C5a lead to the release of histamines, resulting in inflammation and chemotaxis.

Inflammatory mediators such as bradykinin and histamine cause blood vessels to _____.
increase permeability
lengthen
vasodilate
vasoconstrict

Vasodilation of the blood vessel causes the diameter to increase and allow the flow of more blood to the site of inflammation.

Leukocytes have the ability to cross the vessel wall out of the blood stream and into the tissues. This process is known as _____.
diapedesis
apoptosis
phagocytosis
phagocytosis

Diapedesis means "across" and "foot," which explains how the leukocytes use a false foot to cross through gaps between the endothelial cells.

Acute and chronic inflammations differ in that acute inflammation _____.
develops quickly, ends quickly, and is typically beneficial
always involves a fever
develops slowly, lasts a long time, and is potentially damaging
involves the formation of pus

Acute inflammation has a quick onset and is quick to heal with a mostly beneficial purpose.

A response that is uniquely directed against pathogenic Bordetella pertussis would involve what component?
Inflammation
Skin barrier
Antibodies
The complement system

Antibodies

First line defenses have what aspect in common with each other?
They are physical barriers against invading pathogens.
They involve unique cells that attack invading pathogens.
They involve the production of antibodies.
They recognize specific pathogens.

They are physical barriers against invading pathogens

Both the innate and adaptive defenses of the immune system work to prevent
colonization by pathogens.
penetration by invading pathogens.
disease.
the penetration and colonization by pathogens, and the diseases they cause.

the penetration and colonization by pathogens, and the diseases they cause.

If a new bacterial pathogen entered a human body through an accidental needle stick, the first cell that would try to kill the pathogen would likely be
an antibody-producing cell.
a phagocyte.
a cytotoxic T cell.

a phagocyte

An inflammatory response would result from which of the following?
A headache
Vomiting
Jellyfish sting

Jellyfish sting

If a person turns their ankle, how would one determine if damage to the tissue in the ankle has occurred?
The ankle is very warm to the touch.
The ankle is red.
The ankle swells.
The ankle is red, swollen, and warm to the touch.

The ankle is red, swollen, and warm to the touch.

What is the function of inflammation in response to a burn from a hot iron?
To repair the damaged tissue
To destroy the agent causing injury
To destroy the agent causing injury, to limit the effects of the agent on the rest of the body, and to repair the damaged tissue
To limit the effects of the agent on the rest of the body

To repair the damaged tissue

Phagocytosis is defined as
cells of the immune system that ingest pathogens.
the uptake of liquid material by a eukaryotic cell.
the ingestion of solid material by a eukaryotic cell.
the feeding of protozoans.

the ingestion of solid material by a eukaryotic cell.

How is phagocytosis in the immune system different from protozoan phagocytosis?
There is no difference between the two.
Protozoan phagocytosis is used to fight infection; phagocytosis by immune cells is used to feed the cells.
Protozoan phagocytosis is used for feeding; phagocytosis by immune cells is used to fight infection.

Protozoan phagocytosis is used for feeding; phagocytosis by immune cells is used to fight infection.