While the relationship among the zang-fu organs is quite a complicated matter--so much so that (so such an extent that )it deserves to be devoped a lot of pages, yet, thanks to TCM's concise and brilliant summarization, it may just as well be briefed in a broad outline. In TCM, the zang organs pertain to yin and are thought of as interior, while the fu-organs to yang and, naturally enough, as exterior. The interior-exterior relationship between them is formed by the connections of their meridians. This relationship as well as their physiological cooperation and pathological interaction can be clearly seen in the interrelations between the heart and the small intestine, the lung and the large intestine，the spleen and the stomach, the liver and the gallbladder and the kidney and the urinary bladder.|
The heart and the small intestine are connected by the heart meridian and the small intestine meridian to form an exterior-interior relationship. Thus making the two pathologically related to each other. The excessive heart-fire tends to go into the small intestine resulitng in oliguria, burning pains during urination,etc. Conversely, the excessive heat in the small intestine may go upward along the meridian to the heart and cause internal hyperactivity of heart-fire. Leading to dysphoria, crimson tongue, oral ulceration and so on.
The lung and the large intestine form an exterior-interior relationship by mutual connections of their meridians. The dispersing and deseending functions of the lung help the large intestine to perform its transporting task. When the lung functions normally, the large intestine does well. Conversely when the descending function of the lung qi do not work well, it will affect the functionof the large intestine in transportation, causing difficult bowel movements. On the other hand, loose stools and the stoppage of fu-qi may affect the descent of lung-qi, giving rise to asthmatic cough and chest distress.
Both the stomach and the spleen lie in the middle energizerand are connected by their meridians to form an exterior-interior relationship. The stomach governs the reception, while the spleen governs the transportation and transformation. The relationship between the two is that "the spleen conveys the booy fluid for the stomach". If pathogenic damp attacks the spleen, it will injure the transporting and transforming functions of the spleen and affect the reception and the descending action of the stomach, resulting in poor appetite, vomiting, nausea and gastric distention. So the spleen and the stomach share out the work and cooperate with each other to jointly accomplish the task of the digestion, absorption and distribution of food. On the contrary, intemperance of food intake (improper diet)and dyspeptic retention of the stomach will bring about both the dysfunction of the stomach in descent but that of the spleen's transportation and transformation, causing such symptoms as abdominal distention, diarrhea.
The gallbladder is attached to the liver, and they are connected by their meridians to form an exterior-interior relationship. Bile derives from surplus qi of the liver. It is stored and excreted by the gallbladder located under the liver. Only when the liver performs its function successfully can bile be secreted, stored and excreted normally. On the other hand, when bile is excreted properly, the liver can give full play to its function in regulating the normal flow of qi. Conversely, when bile fails to be excreted normally, the liver function will be affected, too. Therefore, the liver and gallbladder are closely related physiologically and pathologically. The diseases of liver often involve the gallbladder and the contrary is also true. Therefore, the liver and gallbladder cannot be completely separated physiologically and pathologically. For example, excessive fire of both the liver and the gallbladder may present such symptoms as qi-stagnation and heat-dampness.
The kidney and urinary bladder, like the other zang-fu organs, form an exterior-interior relationship through their meridians. The kidneys control opening and closing, while the urinarybladder governs storing and excreting urine. Both are related to water metablism. Whether the function of the urinary bladder is normal or not depends on the sufficiency or deficiency of kidney-qi. When kidney-qi is sufficient and its astringency is right, the urinary bladder will open and close regularly, thus maintaining normal water metabolism. In case kidney-qi is deficient, there will be the disturbance of its qi transformation and astrictive action, causing the irregular opening and closing of the urinary bladder, manifested as dysuria, incontinence of urine, enuresis and frequency of micturition.
So far the text has just briefly discussed the relationship between the five zang-and the six fu-organs. To have a thorough understanding of their interrelations and the zang-fu theory, it is also important to know the relationship between the five zang-organs and that between the six fu-organs as well, which, as space is limited, have to be reluctantly parted with here.
In short, although the zang-and fu-organs have different physiological functions, there is a close relationship between them in maintaining the normal functions of the body, and it is the meridian-collateral system that makes them internally-externally interconnected. Without the interconnecting pathways of the meridians and collaterals, each of the zang-fu organs would become an isolated and static organ and unable to perform its functional activities. A case in point to show the relationship is what is said in Basic Questions . "The zang-organs are all connected with the meridians to perform the circulation of qi and blood."