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RESPIRATORY PHYSIOLOGY

Intrapulmonary Circulatior

Pulmonary voin

Bfonchial artery (from left side of heart, via aorta)

Septum

Pulmonary artery (from right side of heart)

FlC.URE 5.13 iNTRAPULMONARy BlOOD ClRCULATION

Blood from the right ventricle ot the heart pcrfuses ihi* lungs (via the pulmonary artery) at a relativeły high ratę <approximately

5    L/min) but under Iow prcssure (driving pressure of about

6    mm Hg>. Pulmonary capillary plexu$es envelop the alveolar sacs, where most of thr gas ex<hange occurs. Pulmonary veins

rollect the oxygenated blood and return it to the left side of the heart for distribution to the sysiemic circulation. In a normal resting adult, the lungs contain about 75 niL of blood distributed variably ac ross its vasculature.

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