Which of the following pressures must remain negative to prevent lung collapse?

atmospheric pressure
intrapulmonary pressure
intrapleural pressure
transpulmonary pressure

Which of the following maintains the patency (openness) of the trachea?

surface tension of water
surfactant production
pseudostratified ciliated epithelium
C-shaped cartilage rings

Which of the disorders below is characterized by destruction of the walls of the alveoli producing abnormally large air spaces that remain filled with air during exhalation?

pneumonia
coryza
emphysema
tuberculosis