The lungs are situated in the thoracic cavity and have the throat as their door and the nose as their outlet. They are a yin organ, and form a yin/yang relationship with the large intestine, which is yang. The lungs are in charge of the respiratory energy or vital Qi of the air. The flow of vital Qi in your body begins when you take your first breath, and ends when you exhale your last breath. When the lungs fail to control respiratory Qi properly, this causes a cough, asthma or difficult breathing.
After foods have passed through the stomach and spleen and have been digested properly, they are mixed with the clear energy of the lungs to become important ingredients of true energy or vital Qi for distribution throughout the entire body. When the lungs fail to distribute this Qi properly, you have symptoms such as fatigue, weakness, shortness of breath, feeling too tired to talk and having excessive perspiration. These are all symptoms of the syndrome called Qi deficiency of the lungs.
The lungs should be able to expand so that air can go in through the nose and mouth easily. When the lungs fail to expand, you have a congested or constricted chest.The lungs should be able to push energy downward through the motion of the diaphragm and when they fail to do so, cough, asthma, scanty urine or edema may occur.
The lungs are in charge of opening and regulating waterways. The circulation of the body fluids is a function of many organs working together as a team, including the lungs. Under normal circumstances, the lungs are capable of sending fluids downward to the kidneys, which pass the fluids to the bladder for excretion. When a pathogenic energy attacks the lungs to impair their normal functions it will lead to symptoms as diminished urination and edema, which is why in Chinese medicine we often say that the lungs are the upper source of water in the body.
The lungs are also in charge of the voice, because the production of the voice and the functions of the lungs are closely related to one another. When the lungs are full of Qi or energy, the voice will be loud, when the lungs are suffering from Qi deficiency, the voice will be feeble. Cold and wind may attack the lungs to cause Qi congestion in the lungs, which will give rise to hoarseness or the loss of voice.
The lungs use the nose as an outlet. The nose is the passage through which air comes and goes, so it is directly related to the lungs. While the lungs are functioning normally, air will go through the nose very smoothly and there will be a normal sense of smell. When the lungs are diseased, it will give rise to nasal congestion, nasal discharge and an impaired sense of small. In severe cases there may be a flaring of the nostrils and difficult breathing.
The lungs are in charge of the skin and the hair. The skin and hair are the outermost regions of the human body and the lungs send defensive Qi and body fluids to them for nourishment. When the Qi of the lungs is healthy and normal, the skin and hair will be moist and smooth and the pores will be well guarded. But as soon as the Qi of the lungs becomes deficient, there will be a shortage of defensive Qi and the outermost regions will not be guarded properly, which will give rise to excessive perspiration or dry flaky skin and the common cold.
Both the lungs and the heart are situated above the diaphragm, with the lungs in charge of Qi (energy) and the heart in charge of the blood. When the Qi flows, the blood circulates and when Qi congestion or stagnation occurs, blood circulation is impaired (cold hands and feet, varicose veins....) The lungs and the heart work together to control energy flow and blood circulation.
The lungs are in charge of Qi and the spleen can produce Qi (called post-natal Qi). This means that lung diseases can, in many cases, be treated by tonifying or boosting the spleen energy or Qi. For example, a chronic cough with a great deal of white phlegm or sputum can be treated this way.
The lungs and the large intestine form a yin-yang relationship with each other. Therefore a cough and asthma due to excessive heat in the lungs can be treated by sedating the large intestine to clear up the sputum heat, so the energy of the lungs will move downward, producing relief in the cough/asthma. And constipation, which is a symptom of the large intestine, may be due to Qi deficiency of the lungs, in which care the Qi of the lungs should be strengthened to relieve the constipation.