Lung governs regulation of the waterways

Also lung governs movement of water. The spleen, lung, kidney, intestines, and bladder are jointly responsible for regulating water metabolism. The specific role of the lung is called governing regulation of the waterways, and represents a combination of the two functions of diffusion and depurative downbearing. By the diffusion of lung qì, fluids are distributed throughout the body, particularly to the skin, where they leave the body in the form of sweat. By depurative downbearing, waste water is conveyed down to the kidney and bladder to be discharged from the body. For this reason, it is said, The lung is the upper source of water. If diffusion is impaired, then the interstices will close up, and thereby prevent sweating. If downbearing is impaired, there may be water swelling and inhibited urination or scant urine.