22.E: Respiratory System Infections (Exercises)
22.1: Anatomy and Normal Microbiota of the Respiratory Tract
The upper respiratory tract is colonized by an extensive and diverse normal microbiota, many of which are potential pathogens. Few microbial inhabitants have been found in the lower respiratory tract, and these may be transients. Members of the normal microbiota may cause opportunistic infections, using a variety of strategies to overcome the innate nonspecific defenses (including the mucociliary escalator) and adaptive specific defenses of the respiratory system.
Multiple Choice
Which of the following is not directly connected to the nasopharynx?
- middle ear
- oropharynx
- lacrimal glands
- nasal cavity
- Answer
-
C
What type of cells produce the mucus for the mucous membranes?
- goblet cells
- macrophages
- phagocytes
- ciliated epithelial cells
- Answer
-
A
Which of these correctly orders the structures through which air passes during inhalation?
- pharynx → trachea → larynx → bronchi
- pharynx → larynx → trachea → bronchi
- larynx → pharynx → bronchi → trachea
- larynx → pharynx → trachea → bronchi
- Answer
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B
The ___________ separates the upper and lower respiratory tract.
- bronchi
- larynx
- epiglottis
- palatine tonsil
- Answer
-
C
Which microbial virulence factor is most important for attachment to host respiratory tissues?
- adhesins
- lipopolysaccharide
- hyaluronidase
- capsules
- Answer
-
A
Fill in the Blank
Unattached microbes are moved from the lungs to the epiglottis by the _______ effect.
- Answer
-
mucociliary escalator
Many bacterial pathogens produce _______ to evade phagocytosis.
- Answer
-
capsules
The main type of antibody in the mucous membrane defenses is _______.
- Answer
-
IgA
_______ results from an inflammation of the “voice box.”
- Answer
-
Laryngitis
_______ phagocytize potential pathogens in the lower lung.
- Answer
-
Alveolar macrophages
Short Answer
Explain why the lower respiratory tract is essentially sterile.
Explain why pneumonia is often a life-threatening disease.
Critical Thinking
Name each of the structures of the respiratory tract shown, and state whether each has a relatively large or small normal microbiota.
(credit: modification of work by National Cancer Institute)
Cystic fibrosis causes, among other things, excess mucus to be formed in the lungs. The mucus is very dry and caked, unlike the moist, more-fluid mucus of normal lungs. What effect do you think that has on the lung’s defenses?
Why do you think smokers are more likely to suffer from respiratory tract infections?
22.2: Bacterial Infections of the Respiratory Tract
The respiratory tract can be infected by a variety of bacteria, both gram positive and gram negative. Although the diseases that they cause may range from mild to severe, in most cases, the microbes remain localized within the respiratory system. Fortunately, most of these infections also respond well to antibiotic therapy.
Multiple Choice
Which of the following does not involve a bacterial exotoxin?
- diphtheria
- whooping cough
- scarlet fever
- Q fever
- Answer
-
D
What disease is caused by Coxiella burnetii ?
- Q fever
- tuberculosis
- diphtheria
- walking pneumonia
- Answer
-
A
In which stage of pertussis is the characteristic whooping sound made?
- convalescence
- catarrhal
- paroxysmal
- prodromal
- Answer
-
C
What is the causative agent of Q fever?
- Coxiella burnetii
- Chlamydophila psittaci
- Mycoplasma pneumoniae
- Streptococcus pyogenes
- Answer
-
A
Which of these microbes causes “walking pneumonia”?
- Klebsiella pneumoniae
- Streptococcus pneumoniae
- Mycoplasma pneumoniae
- Chlamydophila pneumoniae
- Answer
-
C
Fill in the Blank
Calcified lesions called _______ form in the lungs of patients with TB.
- Answer
-
Ghon complexes
An inflammation of the middle ear is called _______.
- Answer
-
otitis media
The _______ is used to serologically identify Streptococcus pneumoniae isolates.
- Answer
-
quellung reaction
_______ is a zoonotic infection that can be contracted by people who handle birds.
- Answer
-
Psittacosis
The main virulence factor involved in scarlet fever is the _______.
- Answer
-
erythrogenic toxin
Short Answer
Name three bacteria that commonly cause pneumonia. Which is the most common cause?
How does smoking make an individual more susceptible to infections?
How does the diphtheria pathogen form a pseudomembrane?
Critical Thinking
Why might β-lactam antibiotics be ineffective against Mycoplasma pneumoniae infections?
Why is proper antibiotic therapy especially important for patients with tuberculosis?
22.3: Viral Infections of the Respiratory Tract
Viruses cause respiratory tract infections more frequently than bacteria, and most viral infections lead to mild symptoms. The common cold can be caused by more than 200 viruses, typically rhinoviruses, coronaviruses, and adenoviruses, transmitted by direct contact, aerosols, or environmental surfaces. Due to its ability to rapidly mutate through antigenic drift and antigenic shift, influenza remains an important threat to human health. Two new influenza vaccines are developed annually.
Multiple Choice
Which of the following viruses is not commonly associated with the common cold?
- coronavirus
- adenovirus
- rhinovirus
- varicella-zoster virus
- Answer
-
D
Which of the following viral diseases has been eliminated from the general population worldwide?
- smallpox
- measles
- German measles
- influenza
- Answer
-
A
What term refers to multinucleated cells that form when many host cells fuse together during infections?
- Ghon elements
- Reye syndrome
- Koplik’s spots
- syncytia
- Answer
-
D
Which of the following diseases is not associated with coronavirus infections?
- Middle East respiratory syndrome
- German measles
- the common cold
- severe acute respiratory syndrome
- Answer
-
B
Which of these viruses is responsible for causing shingles?
- rubella virus
- measles virus
- varicella-zoster virus
- variola major virus
- Answer
-
C
Fill in the Blank
The _______ virus is responsible for causing German measles.
- Answer
-
rubella
A(n) _______ is an uncontrolled positive feedback loop between cytokines and leucocytes.
- Answer
-
cytokine storm
In cases of shingles, the antiviral drug _______ may be prescribed.
- Answer
-
acyclovir
The slow accumulation of genetic changes to an influenza virus over time is referred to as _______.
- Answer
-
antigenic drift
The _______ vaccine is effective in controlling both measles and rubella.
- Answer
-
MMR
Short Answer
Since we all have experienced many colds in our lifetime, why are we not resistant to future infections?
Critical Thinking
What role does the common cold have in the rise of antibiotic-resistant strains of bacteria in the United States?
Why is it highly unlikely that influenza A virus will ever be eradicated, like the smallpox virus?
22.4: Respiratory Mycoses
Fungal pathogens are ubiquitous in the environment. Serological studies have demonstrated that most people have been exposed to fungal respiratory pathogens during their lives. Yet symptomatic infections by these microbes are rare in healthy individuals. This demonstrates the efficacy of the defenses of our respiratory system. In this section, we examine some of the fungi that can cause respiratory infections.
Multiple Choice
Which of these infections is also referred to as Valley fever?
- histoplasmosis
- coccidioidomycosis
- blastomycosis
- aspergillosis
- Answer
-
B
Which of the following is not caused by a dimorphic fungus?
- histoplasmosis
- coccidioidomycosis
- blastomycosis
- aspergillosis
- Answer
-
D
Which of the following is caused by infections by bread molds?
- mucormycosis
- coccidioidomycosis
- cryptococcosis
- Pneumocystis pneumonia
- Answer
-
A
In the United States, most histoplasmosis cases occur
- in the Pacific northwest.
- in the desert southwest.
- in the Mississippi river valley.
- in Colorado river valley.
- Answer
-
C
Which of the following infections can be diagnosed using a skin test similar to the tuberculin test?
- histoplasmosis
- cryptococcosis
- blastomycosis
- aspergillosis
- Answer
-
D
Fill in the Blank
In coccidioidomycosis, _______ containing many endospores form in the lungs.
- Answer
-
spherules
In cryptococcosis, the main fungal virulence factor is the _______, which helps the pathogen avoid phagocytosis.
- Answer
-
capsule
In some mycoses, fungal balls called _______ form in the lungs
- Answer
-
aspergillomas
Most US cases of coccidioidomycosis occur in _______.
- Answer
-
the desert southwest
Coccidioidomycosis may develop when Coccidioides immitis _______ are inhaled.
- Answer
-
arthrospores
Short Answer
Which pulmonary fungal infection is most likely to be confused with tuberculosis? How can we discriminate between these two types of infection?
Compare and contrast aspergillosis and mucormycosis.
Critical Thinking
Why are fungal pulmonary infections rarely transmissible from person to person?