<prompt> Type of blood flow seen in the apex of the lung isNo flow, PALV PpcIntermittent flow, PALV Ppc during diastoleIntermittent flow, PALV Ppc during systoleContinuous flow, PALV Ppc  <response>: Zone 2: Intermittent blood flow only during the peaks of pulmonary aerial pressure Ppc because the systolic pressure is then greater than the alveolar air pressure PALV, but the diastolic pressure is less than the alveolar air pressure. 