<prompt> A 49-year-old man has a pulmonary embolism that completely blocks blood flow to his left lung. As a result, which of the following will occur?Ventilationperfusion VQ ratio in the left lung will be zeroSystemic aerial PO2 will be elevatedVQ ratio in the left lung will be lower than in the right lungAlveolar PO2 in the left lung will be approximately equal to the PO2 in inspired air  <response>: Alveolar PO2 in the left lung will equal the PO2 in inspired air-No blood flow to the left lung- No gas exchange between the alveolar air and the pulmonary capillary blood-Consequently, O2 is not added to the capillary blood. The ventilationperfusion VQ ratio in the left lung will be infinite not zero or lower than that in the normal right lung because Q the denominator is zero. Systemic aerial PO2 will, of course, be decreased because the left lung has no gas exchange. Alveolar PO2 in the right lung is unaffected. 