Suwen‧Lingcang Secret Classic Discussion records: "The heart is the official of the monarch, from which mental activity arises." Suwen-Tiaojing Lun: "The heart stores the spirit." The term "monarch" is a feudal term, signifying command and supremacy, meaning that the heart holds the primary position among the zang-fu organs. "Mental activity" or "spirit" refers to the functional activities of the higher central nervous system. These functions are presided over and manifested by the heart, hence the saying "the heart governs mental activity." This indicates that the ancients' understanding of the heart included the functions of the central nervous system. Under the influence of the heart's central nervous system activity, the zang-fu organs and the qi and blood of the human body carry out unified and coordinated physiological activities. If the heart is diseased and loses its commanding role over mental activity, the physiological functions of other zang-fu organs will also be affected.