19 Questions
What is the main cause of the development of pulmonary edema?
Increased left atrial pressure exceeding plasma colloid osmotic pressure
What happens when alveolar O2 decreases to ~70% of normal?
Adjacent vessels constrict, increasing resistance by 5x
What is the mean pulmonary capillary pressure?
About 7 mm Hg
What happens to the pulmonary capillaries when alveoli apply little to no pressure at end-exhalation?
Pulmonary capillaries are compressed
What is the main effect of alveolar vs extra-alveolar vessels on pulmonary vascular resistance?
Alveoli-filled alveoli compress capillaries, whereas larger vessels are pulled open further by elastic recoil
What happens to the resistance when alveolar O2 decreases to ~70% of normal?
Adjacent vessels constrict, increasing resistance by 5x
What happens to the cardiac output during exercise?
It can increase 4-7 times
What is the main accommodation to increased cardiac output?
Increase number of open capillaries ('Recruitment')
What are the outward fluid pressures from capillaries into interstitium?
Capillary pressure, 7 mm Hg
What happens as left atrial pressure rises in the development of pulmonary edema?
Pulmonary capillary pressures rise by about 1-2 mm Hg more
What is the effect of increased left atrial pressure exceeding plasma colloid osmotic pressure?
Fluid begins to accumulate in the lungs
Which of the following best describes the major functions of the bronchial circulation?
Supplying oxygenated blood to the conducting airways and supporting lung tissue metabolism
In which zone of the lung do alveolar pressure exceed pulmonary vascular pressure?
Zone one
How does pulmonary vascular resistance change with alterations in cardiac output or pulmonary arterial pressure?
It may change due to distention and recruitment of pulmonary vessels
What is the consequence of hypoxic pulmonary vasoconstriction on the distribution of pulmonary blood flow?
It redirects blood flow away from poorly-ventilated areas of the lung
How does inspired nitric oxide affect pulmonary vascular resistance and hypoxic vasoconstriction?
It decreases pulmonary vascular resistance and inhibits hypoxic vasoconstriction
Which of the following best describes the regional differences in pulmonary blood flow in an upright person?
Greater blood flow to the base of the lung compared to the apex
What describes zone two in the lung with respect to pulmonary vascular pressure and alveolar pressure?
Pulmonary vascular pressure exceeds alveolar pressure but is less than arterial pressure
How does pulmonary vascular resistance change with alterations in lung volume?
It changes due to alterations in alveolar and extra-alveolar blood vessels
Test your knowledge of pulmonary blood flow with this quiz covering the major functions of the bronchial circulation, the contrast between systemic and pulmonary circulations in response to hypoxia, and the regional differences in pulmonary blood flow. Ideal for respiratory physiology students and those studying Guyton's Ch. 39.
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