TCM refers the gallbladder, the stomach, the large intestine, the small intestine, the urinary bladder and the triple energizer to the six fu-organs. it is not only that, besides the functions of their own, they are characterized by their common role ofdecomposing and digesting water and food, and discharging the wastes, but that, in the process of digesting and absorbing food and excreting the wastes, they are closely related to each other both physiologically and pathologically. Their functional feather is excretion without storage and taking descending and unobstruction as their normal functional state. TCM’s rational knowledge of the interrelationship of the six fu-organs is well grounded on ancient anatomical knowledge, the observation of the physiological and pathological changes of the six fu-organs and the summarization of long-term and rich medical experience.

Food entering the stomach is decomposed into chyme which after digested by the stomach, is transported to the small intestine in which it is further digested by means of bile excreted by the gallbladder. The small intestine “separates the clear from turbid”.The clear, refers to food essence, is transported and distributed to all parts of the body by the spleen; while the turbid is the residues of water and food. Of them waste water goes into the kidney, and then into the urinary bladder where it is turned into uruie to be excreted from the body. And the other is conveyed to the large intestine where it is changed into feces and leaves the body via the anus. In the whole process of the transportation and transformation of water and food, the triple energizer dominates qi transformation and qi movement of the whole body.

The triple energizer is one ot the six fu-organs, and among all the zang-fu organs, it is the largest fu-organ in the human body. Huangdi’s Classic on Medicine holds: “The triple energizer is separated from the zang-fu organs and yet is within the body. It encloses all organs and is the largest one.” And the book also advanced a viewpoint that “The triple energizer exists in name only but is not the entity”. Triple energizer has no exterior-interior relationships with the zang-organs, it is therefore called “solitary fu-organ”. Its main functions are to pass various kinds of qi and to serve as the pathway for body fluid. It is divided into three parts: the upper energizer, middle energizer and lower energizer. The triple energizer with the related zang-fu organs, each having its own function to perform, accomplish jointly a complicated physiological process in the digestion, absorption, distribution and excretion.

The upper energizer refers usually to the part above the diaphragm, including the heart, lungs and head as well. Its main physiological function is to distribute essence-qi throughout the body. In other words, in combination with the heart and the lung, the upper energizer distributes essence-qi to the whole body to warm and nourish the skin and muscles, tendons and bones. This function is described in Miraculous Pivot “The upper energizer resembles a sprayer.” This is a metaphor, which is used to describe the function of the upper energizer to sprinkle fog-like cereal essence.

The middle energizer refers mainly to the abdorminal part between the diaphragm and umbilicus, and includes such zang-fu organs as the spleen, stomach, liver and gallbladder. Its main physiological functions are to decompose food and transform nutrient substances into qi and blood, and to discharge the wastes and steam body fluid. This function is mentioned in Miraculous Pivot: “The middle energizer is likened to a fermentation tun.” By “fermentation tun” is meant the place where food is decomposed and digested.

The lower energizer refers, generally, to the portion located below the stomach, including the small intestine, large intestine, kidneys, urinary bladder. etc. Its main function is to discharge food residuces and urine. So there is also a saying in Miraculous Pivot, “The lower energizer works like a sewer.” Here “sewer” is used to describe the function to excrete the wastes. However, with the development of visceral manifestations (zang xiang), essence and blood of the liver and kidney as well as primordial qi are generally attributed to the lower energizer by later generations.

In short, the triple energizer dominates all kinds of qi and qi transformation of the human body, and serves as the pathway for water. Therefore, Basic Questions says: “The triple energizer, as the waterways, is an organ in charge of the water circulation, flowing along the waterways.”

While the six fu-organs transport and tranform water and food, the process of reception, digestion, transportation and excretion are also in progress. The six fu-organs are usually in a state of the alternations between emptiness and fullness. And they transform food into essence but not store it. That’s why TCM believes: ” the six fu-organs function well when they are unobstructruction, the unobstructed is the normal functional state for the six fu-organs; where the regular descent is their normal functional activities.”Pathologically, disorders among the six fu-organs often affect each other. For instance, when body fluid is consumed because of excessive heat in the stomach, the large intestine is bound to have trouble in transportation, and, in consequence, constipation occurs. A disturbance of the large intestine in transmission and transformation not only leads to the obstruction of the large intestine itself, but also affects the regular descent of stomach-qi, causing repeated vomiting. A dominant gallbladder fire often interferes with the stomach and results in vomiting bitter fluid.Dampness and heat accumulated in the stomach and spleen burn and steam the liver and the gallbladder. This may cause the bile to overflow, and give rise to jaundice.

Apart from the six fu-organs, there are the brain, marrow, bones, vessels, gallbladder and uterus termed the “extraordinary fu-organs”. Like the fu organs morphology, the extraordinary fu-organs are mostly hollow but not the pathways for the digestion and excretion of cereal food and, like the zang argans functionally, they also store essence-qi. With the exception of the gallbladder, they have no exterior-interior relationships.

The brain is located in the skull and connects with the spinal marrow. It is the organ of spirit, consciousness and thinking. Basic Question says: “The head is the house of intelligence”.(，the head is the residence of intelligence)Li Shizhen of the Ming Dynasty pointee out, “The brain is the seat of the mind”, and the heart governs all funcctions of the whole body, including mental activities. In the Qing Dynasty, Wang Qingren stated: “The intelligence and memory onginate from the brain but not from the heart.” And he also considered: “Thinking, memory, vision, hearing, smelling and speaking are all controlled by the brain.” Although TCM has some knowledge of the brain’s physiology and pathology, it still ascribes the functions of the brain to the heart, the liver and respectively to the five zang-organs, and holds that spirit, consciousness and thinking are related to the five zang-organs.

The uterus, or womb(wu：m), situated in the lower abdomen posterior to the urinary bladder in women, is an inverted pear-shaped organ where menstruation occurs and the foetus is bred. They are two complex physiological processes in which tiangui, a kind of refined nutritious substance transformed from the kidney-essence, plays the most important role. Both Chong and Ren meridians originate from the uterus. The uterus is also closely related to the heart, liver and spleen, because normal menstruation and the nourishment of the foetus rely on the blood dominated by the heart, stored by the liver and controlledby the spleen. Therefore the dysfunction of the above organs will affect the normal functions of the uterus, bring about menstrual disorder and sterility.

It should be pointed out that according to the theory of visceral manifestation, the names of the zang-fu organs correspond to those of the modern human anatomy and refers to the substantial internal organs. However, in the physiology and patholoty, the knowledge of TCM differs greatly from that of western medicine, which has been learnt a lot from the above.