Physiological Function of the Spleen
1) Dominating Transportation and Transformation
"Transportation" implies assimilation and distribution. For example, conveying and distributing the essential substances of the body. "Transformation" implies changes, digestion and absorption, which mainly indicate digestion of food and assimilation of the essential substances of food and drink. The main physiological function of the spleen is to dominate transportation and transformation. Together with the stomach and small intestine, it is responsible for the digestion, assimilation and distribution of the essential substances of drink and food throughout the body. Thus Chapter 8 in the Plain Questions states.. "The spleen and stomach are barn officials who are responsible for transforming the five flavors. " This function of the spleen involves transportation and transformation of the drink and food on the one hand, and of water-dampness on the other.
All kinds of diets are implied under "drink and food. " The transportation and transformation function of this denotes that the spleen digests the diet and assimilates the nutrients. TCM holds that the digestive function of the body is related to the spleen, stomach and small intestine. For example, the diet taken into the stomach is decomposed by both the spleen and stomach, then sent downward into the small intestine to undergo the process of separating the clear from the turbid, The food essence is then conveyed throughout the body, so as to supply the nutrients for the viscera and all organs. The five zang-viscera is taken as the "core" in traditional Chinese medicine. From either the physiological aspect or the pathological, the spleen is a major organ of the digestive system,for the capacity of fulfilling these functions is chiefly attributable to the spleen. Thus Chapter 21 in the Plain Questions states. "Alimentary qi goes into the stomach, and the
essential substance is disseminated to the liver, and to nourish tendons, Alimentary qi goes into the stomach; the turbid essential qi goes up to the heart ; pure essence goes into the vessels, and the vessel-qi flows into the meridians. The lung, to which the meridian qi is subordinate and all vessels meet in the lung, the essential qi is distributed to the surface skin and body hair. " This is a brief explanation of the spleen, which transports and transforms the essential qi of drink and food to the whole body so as to maintain the physiological activities of the five zang-viscera and six fu-viscera, limbs, surface skin and body hair, tendons and bones, etc.
Transportation and transformation of water-dampness implies that the spleen has the function of absorbing, disseminating, and excreting water-dampness. Here, waterdampness refers to aqueous liquid within the body. The spleen plays an important role in regulating water metabolism and maintaining the balance of water metabolism. This function of the spleen is carried out in the following two aspects:
The drink taken into the body is transported and disseminated by the spleen, which is transformed into the body fluids, and conveyed to the lung and heart, here it is further disseminated throughout the body to nourish and moisten the viscera and all organs.
The spleen transmits unusable water-fluid from the metabolism to the relevant organs, such as the lung, kidney, urinary bladder, and surface body hair, etc. Then the excess water is eventually changed into sweat or urine to be excreted from the body.Hence, during the entire process of water metabolism, the spleen plays a pivotal role in promoting the circulation and excretion of water. Thus, Chapter 21 in the Plain Questions states: "Ingested fluids enter the stomach. Here, they are churned and their essential qi is strained off. The essential qi is then carried to the spleen and further distributed by the spleen-@ It goes up to the lung, which ensures regular flow through the water passage down to the bladder. In this way, water-essence is distributed throughout the body and the five meridians. " This is a highly condensed process of water metabolism.This functional activity mainly depends on the spleen-qi. Only when the spleen functions well, can the spleen's ability in digesting and assimilating the nutrients, and transporting and distributing the essential substances be flourishing, the transmission and excretion of water-fluid be normal. This maintains the relative balance of body fluid. Conversely,failure of the spleen in function not only leads to pathological changes of the digestive system, such symptoms as abdominal distension, diarrhea and lassitude, etc. , but also causes disorders of water metabolism. This further results in diseases caused by retention of water-dampness, such as edema, retention of phlegm and fluid, diarrhea, etc.
Drink and food provide a major source of the nutrients required by the body after
birth, and are also the material basis of qi and blood, the foundations of life. The fulfillment of this physiological activity, is mainly attributable to the transportation and transformation of the spleen. The spleen is there{ore considered to be the "acquired foundation", "the source of qi and blood. " In Jin and Yuan Dynasties, the well-known medical doctor Li Dong-yuan, is a representative of "'the school of invigorating the earth. " In his book, Treatise on the Spleen and Stomach, he pointed out that "The internal impairment of the spleen and stomach may lead to many kinds of diseases. " The spleen and stomach have great significance in prevention against diseases and preservation of health, because of being the "acquired foundation. " In daily life, more attention must be paid not only to dietary nutrition, but also to protection of the spleen and stomach.When using herbs in clinical practice, this should be taken into account.
2) In Charge of "Sending up"
"Sending up" refers to rising. Its function is characterized by leading up and ascending. Its content is composed of two parts. The first of these is that the spleen dominates sending the clear upward. "The clear" here, means the essential substances that are extracted from drink and food, and "Sending the clear upward" denotes the ascendance and distribution of the essential substances. The essential substances extracted from the diet is digested and assimilated by the spleen, stomach and small intestine, and is then sent up to the lung to be disseminated to all parts of the body via the heart and lung. This is referred to "sending the qi upward", and if this function of the spleen is normal, all the internal viscera and tissues will obtain enough nutrients and function well. If it is abnormal, dizziness, vertigo, and blurred vision may occur. If clear-yang fails to ascend, there may appear a downward pouring of a mixture of both the clear and turbid qi, producing nocturnal emission, morbid leucorrhea, abdominal distension, and diarrhea. A case of permanent diarrhea is usually accompanied by fatigue, lassitude, shortness of breath and dislike of speech, etc. This is the reason why Chapter 5 in the Plain Questions states:"Descending movement of elear-qi may cause swill diarrhea, ascending movement of turbid-qi may lead to abdominal distension. "
The second component involving the function of the spleen is that it plays a role in stabilizing the internal organs at their original locations. All internal organs of the human body have their own fixed locations, for example, the stomach is located in the epigastriurn, the kidneys in both sides of the loin, the uterus in the lower abdomen, and so on.Traditional Chinese medicine holds that this ability of the spleen to keep the internal organs within certain locations, is attributed to the physiological function of the spleen in domination of sending up. The reason behind this is that the vigor muscles, ligament and tendons that hold and fix the internal organs, also rely on the nourishment of the essential substance of drink and food, which is transported and transformed by the spleen. If spleen-qi descends instead of ascends, it may result in ptosis of the stomach, kidneys and uterus, and prolapse of the anus. The mechanism of pathological change responsible for this is a looseness of ligament and muscle, these being unable to operate the traction of
the internal organs. Ptosis of the internal organs is directly related to the degree in which the spleen is deficient. In treating this disease, one method which is often used is that of reinforcing the middle to maximize the qi while using herbs as the primary treatment.The Middle-Reinforcing and Qi-Benefiting Decoction is often used. Through experimentation, this formula has been shown to stimulate the ligaments and muscles of the internal organs to increase their tensions. Thus, it can be seen that the function of spleen-qi and in dominating ascending and in dominating transportation and transformation are interconnected, and inter-coordinated in both physiology and pathology.
3) Commanding the Blood
Commanding refers to controlling in this context. The phrase "commanding the
blood" means that the spleen functions in controlling the blood in its circulation through the blood vessels and in prevention of extravasation of blood. Its mechanism is referred to as the governing action of spleen-qi to the blood. Since the spleen is the source to growth and development of the qi and the blood, when it's qi is healthy, there is a plentiful supply of blood and qi in the body. The qi is capable of containing blood, thus the blood flows normally within the vessels. If the spleen-qi is unhealthy, the blood will flow abnormally within the vessels, often escaping from them, resulting in various types of hemorrhage, such as blood in the stool, hematuria, purpura, etc. This condition is described as "failure of the spleen to control the blood", and is characterized by prolonged bleeding in the lower parts of the body. In treating these disorders, there are two common clinical practices called: "invigorate the spleen to benefit the qi" and "conduct the blood back to
its vessels. "
