Chapter 8 of the Suwen: The Lung

肺 者 ， 相 傅 之 官 ， 治 節 出 焉 。

The lung holds the office of prime minister and instructor, the regulation of the knots comes from it.

As stated under many of the above symbols, the lung acts as the prime minister within the body, while the heart serves as Emperor. The prime minister is a diplomat, whose job it is to act as the agent or instrument to those that it serves. While it helps with the regulation of the heart through its activities, it is also responsible for the regulation of all of the organs that lay beneath it. It is the job of a minister to serve those who are in want or need of care and various sorts of aid. All of the oxygen in the body is provided by the lung, to the other organs. All of the carbon dioxide in the body is removed by the lung. In this process of breath, the lung serves the entirety of the body and is in constant communication with the other organs and uses its metal quality of judgment to determine what is needed and then translates those needs into the rhythm of the breath.
The lung uses its talents as a communicator in order to instruct the various organs and components of the body in their synchronous  dance. One example of how the lung does this is by regulating its pH balance in order to instruct the hemoglobin molecules to open themselves up for receiving oxygen or to contract themselves down.
節 is literally a picture of bamboo on top of food and a person facing that food about to eat it. The character means “node” or “knot” and it could be that this character symbolizes the idea of the choicest parts of the plant to eat. Within an animal, the choicest parts, or nodes, would be the organs and in the above mentioned way, the lung certainly regulates them by providing them with the much-needed oxygen. Most likely, the Po’s animal-like regulation quality is in charge of this.