Heart - The Zang Organs

The channel of the heart, located in the thorax, leads to the small intestine, and heart is thus externally and internally related to the small intestine. (Each zang organ is linked with a fu organ by a channel, a situation known as external-internal relation.) The heart also opens into the tongue. (Each zang organ opens into a sense organe which indicates a close structural or physiological and pathological relationship between the internal organs and the sense organs.) The main physiological functions of the heart are controlling blood and vessels and housing the mind.

1. Controlling blood and vessels. Vessels are the site of blood containment and circulation, the impulse of the heart sending blood incessantly through the vessels to nourish the whole body. When blood supply is sufficient and blood circulation normal, the complexion will be rosy and lustrous, and vitality full. The tissues and organs are well nourished and function properly.
2. Housing the mind. The heart is considered the main organ governing mental activities and generalizing the physiological function of the brain. Spirit, consciousness, memory, thinking and sleep are well dominated by this function of the heart. The two function of the heart have a mutual effect and correlation. According to Neijing: “The heart dominates the vessels and the vessels supply the mind.”
3. Opening into the tongue. The two functions of the heart, i.e., controlling blood and vessels and housing the mind, are closely related to the color, form, motility, and sense of taste of the tongue. This is also expressed as “the tongue is the mirror of the heart”.