Question 1

Which of the following mechanisms is primarily responsible for keeping the lower respiratory tract nearly sterile?

Accepted Answer

The ciliary escalator that moves particles toward the throat via ciliary action

Question 2

A patient presents with a sore throat, fever, and a tough grayish membrane in the throat. Gram-positive rods are cultured from the membrane. Which pathogen is most likely responsible for these symptoms?

Accepted Answer

Corynebacterium diphtheriae

Question 3

Which of the following best describes the pathogenesis of tuberculosis in the lungs?

Accepted Answer

Bacteria are isolated in walled-off tubercles, which may later rupture and disseminate bacteria

Question 4

Which laboratory test is considered the 'gold standard' for diagnosing streptococcal pharyngitis?

Accepted Answer

Throat culture

Question 5

Which of the following is a key virulence factor of Streptococcus pyogenes that allows it to evade phagocytosis?

Accepted Answer

M protein on the cell surface

Question 6

A child develops a red rash, a 'strawberry' tongue, and peeling skin after a sore throat. Which toxin is responsible for these symptoms in scarlet fever?

Accepted Answer

Erythrogenic toxin

Question 7

Which of the following statements about the DTaP vaccine is correct?

Accepted Answer

It contains diphtheria toxoid to protect against diphtheria

Question 8

Which of the following best explains why antibiotics are not effective in treating the common cold?

Accepted Answer

The causative agents are viruses, not bacteria

Question 9

A 27-year-old man with asthma is hospitalized with a 4-day history of cough and spiking fevers. Gram-positive diplococci are cultured from his blood. Which organism is most likely responsible?

Accepted Answer

Streptococcus pneumoniae

Question 10

Which of the following is a distinguishing feature of Mycoplasma pneumoniae compared to other bacterial pneumonia pathogens?

Accepted Answer

It lacks a cell wall

Question 11

Which of the following is the primary mode of transmission for Legionella pneumophila?

Accepted Answer

Inhalation of aerosols from contaminated water sources

Question 12

Which of the following best describes the structure of the influenza virus?

Accepted Answer

Eight RNA segments enclosed in a protein capsid and lipid envelope with HA and NA spikes

Question 13

Which process is responsible for the emergence of new pandemic influenza strains?

Accepted Answer

Antigenic shift due to reassortment of RNA segments

Question 14

A patient with AIDS develops pneumonia. Microscopy reveals cysts in the alveoli. Which organism is most likely responsible?

Accepted Answer

Pneumocystis jirovecii

Question 15

Which of the following is a common feature of all four major fungal diseases of the lower respiratory system discussed in the chapter?

Accepted Answer

They are all acquired by inhalation of spores or conidia

Question 16

Which of the following statements about COVID-19 is correct?

Accepted Answer

It is primarily transmitted by airborne droplets and aerosols

Question 17

Which of the following best explains why the BCG vaccine is not widely used in the United States?

Accepted Answer

It causes a positive tuberculin skin test and has uneven effectiveness

Question 18

Which of the following is a primary indicator of AIDS in a patient presenting with respiratory symptoms?

Accepted Answer

Pneumocystis pneumonia

Question 19

Which of the following best describes the function of the ciliary escalator in the respiratory system?

Accepted Answer

It moves particles toward the throat to be swallowed or expelled

Question 20

Which of the following is a distinguishing feature of Chlamydia psittaci infection (psittacosis) compared to Chlamydia pneumoniae?

Accepted Answer

It is transmitted by inhaling elementary bodies from bird droppings

Microbial Diseases of the Respiratory System: Structure, Function, and Pathogenesis

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