The Small Intestine
1. Receiving and Absorbing the Food and Drink
Chapter 8 in the Plain Question states. "The small intestine is a receiver in charge of transformation. " The small intestine receives food and drink which have been decomposed by the stomach. Thus, it is like a container for food digested by the stomach, where the pre-digested food remains for a longer time and is further digested, allowing food and drink to be transformed into the essential substances and nourish the whole body. Its dysfunction may lead to disorders of digestion and absorption characterized by abdominal distention, diarrhea, and loose stools, etc.
2. Separation of the Clear and the Turbid
The clear refers to the essential substances, while the turbid denotes the waste after the digestion and absorption of the diet. It consists of three aspects. The first is that it transforms the food already being decomposed by the stomach, which then enters the small intestine to be digested completely. This process is called "transforming food" in TCM. This also refers to the function of the small intestine in separating the clear and the turbid. After separation, the digestate is divided into three parts, the essential substances, waste, and unwanted water containing the waste. The second aspect is that it absorbs the essential substance of food and drink, and transports the waste to the large intestine, The third is that it sends unwanted water into the urinary bladder where it becomes urine.
Thus the small intestine plays an important role in promoting digestion. When this function is normal, the clear and turbid are respectively separated and dealt with. The essential substances are disseminated throughout the body, and the waste descends to the large intestine, while the unwanted water flows to the urinary bladder. If the small intestine is diseased, it leads not only to dysfunction of the digestion, characterized by abdominal pain, and distension, but also affects the excretion of urine and feces, resulting in such symptoms as dysuria, loose stools, etc. Treatment includes what is known as "prcmoting urination to treat diarrhea. "
