Passage IV

The respiratory cycle for resting humans who are breathing normally has been studied by physiologists. The figure shows 4 average measures of the cycle: lung volume, air flow (the rate at which air flows into or out of the lungs), pleural pressure (the pressure in the area between the lungs and the chest wall), and alveolar pressure (the pressure in the alveoli, small sacs in the lungs where air exchange takes place). Pleural pressure and alveolar pressure are represented as values above or below atmospheric pressure (1,033 cm H2O). The next inspiration begins at the end of the pause.

22. According to the information provided, which of the following statements best describes the relationship between alveolar pressure, atmospheric pressure, and the direction of air flow during most of expiration ?

Answer and Explanation

Your Answer is

Correct Answer is J

Explanation

Focus on the fourth line corresponding to the stage of expiration. At this time, alveolar pressure>atmospheric pressure, so exclude F & G;

In addition, if you don’t know expiration, you must also know the prefix ex-. This is what outward means (ie export, exile, extrovert), so of course this is exhaling outward, the gas leaving the lungs