From Plain Questions (素问 sù wèn, líng lán mì diǎn lùn). The heart holds the office of sovereign, and the lung is its assistant. The heart governs the blood, whereas the lung governs qì; the lung therefore helps the heart to carry blood to all parts of the body so that they are all nourished. The ability to influence the heartbeat by controlling respiration as in qì-gong may be further evidence for this relationship. The Inner Classic (内经 nèi jīng) expressed the functions of organs in terms of analogy to government. The lung’s action of conveying essence to the skin and body hair, its connection with defense qì, its role in the production of blood, its regulation of the waterways through all three burners, means that it has a supporting role in many functions within the economy of the body.