TCM Physiological Theory


The Yang Energy System

There are 2 types of qi. One is congenital qi ( Hsiantian ) and the other is acquired qi ( Houtian ). Congenital qi is qi of the organs and channels, and it is acquired from the parents. In acquired qi, there is nutrient qi ( Yingqi ) which circulates in the vessels and supplies mainly the viscera, and defensive qi (Weiqi) which circulates outside the vessels and is mainly distributed in the muscles and skin. It (Weiqi) nourishes the subcutaneous tissues, controls the opening and closing of the pore and defends the body against infection.

Both acquired qi and congenital qi meet in the chest at the centre cavity ( Zhongiao ) of the middle warmer of the Sanjiao to form the essential qi ( zongqi ) which nourishes the heart and lung to promote blood circulation and respiration respectively.


The liver is situated at the right hypochondriac region, its connecting fu organ is the gall bladder. The functions of the liver are:

It regulates the blood flow to the tissues and organs and also influences menstruation. During rest, part of the blood remains in the liver, while during activity, blood is released and this release of blood is controlled by the liver.

Prolonged anger weakens the qi of the liver so that the liver will not function properly leading to headache, upset of stomach and costal region pain, fainting spells and even vommitting of blood. On the other hand a dysfunction of the liver leads to constant anger.

The liver promotes the function of the spleen and stomach in digestion and absorption. It affects the secretion of bile and excretion into the intestine.

When there is sufficient qi in the liver the tendons are strong and extension and flexion are free.

The liver controls the eyes and the growth of the nail.

Anger and the taste of sourness will affect the liver. The colour green relates to the liver and responds to the tendon system.


The Yin Energy System

Blood and qi are closely related. The formation and circulation of blood depend on the qi while formation and distribution of qi depend on the blood to carry it to the various organs. A deficiency of blood will lead to a deficiency of qi, while a deficiency of qi will lead to a deficiency of blood. A stagnation of qi will bring about a stagnation of blood and a stagnation of blood will lead to a stagnation of qi causing pain to the organs.

Blood is formed from:
The essence of the kidney which produce bone marrow which in turn produce blood.

The qi of the kidney promotes the transportation of essence of food, absorbed by the spleen and stomach, to the lung where waste qi is given up and clean qi is inhaled. This essence is sent to the heart which pumps it to all parts of the body to nourish the body. The liver stores the blood which controls its release. The spleen governs its circulation within the blood vessels.


The heart is situated in the thorax, its connecting fu organ is the small intestine. The functions of the heart are :

It pumps out blood through the blood vessels to the tissue and organs carrying nutrient to nourish the tissue and organs for the proper functioning of the tissue and organs.

It governs the mental activities and physiological function of the brain. Spirit, consciousness, memory, sleep and thinking are all dominated by the heart.

The essence of the heart comes to the tongue, and this energy can be seen in the face. A pink face shows proper circulation of the qi, a red face indicates the qi is too active and a pale face indicates a lack of qi of the heart.

Excessive joy and the taste of bitterness will affect the heart.

The colour red relates to the heart and responds to the vessel and brain function.


The kidney is situated at the lumbar region. The connecting fu organ of the kidney is the urinary bladder. The functions of the kidney are:

The qi of the kidney consists of congenital qi and acquired qi and it is this essence called the life force of the body which influences the production, the growth and the development of human body. It stores the congenital qi of the five viscera.

The kidney stores essence which can produce marrow inlcuding the spinal cord and bone marrow. The spinal cord connects to the brain, while the bone marrow nourishes the bone and manufactures blood.

The kidney divides the body fluid, sent down by the lung’s descending function, into clear fluid which is retained in the body and turbid fluid which flow into the urinary bladder and excreted as urine.

When air is inhaled by the lung, its distribution to the whole body depends on the kidney’s energy of reception and control. If the kidney’s energy or life force is weak, breathlessness will occur.

The kidney opens into the ear and hearing depends on the qi of the kidney. The qi of the kidney also controls the growth of hair on the head.

Fear and the taste of saltiness will affect the kidney.

The colour black indicates the kidney and influence the bones, joints and nerve system.


The spleen is situated at the left hypochondriac region, its communicating fu organ is the stomach. The functions of the spleen are :

It is responsible for the digestion and absorption of food and carrying its essential substances to the heart and lung where they are sent to nourish the whole body.

The spleen governs the blood circulating within the blood vessels to prevent abnormal bleeding.

The spleen qi ascends and as such sends the nutrient to the lung to transform into blood and qi. In the process of transforming and transporting, it enables the muscles to receive the nutrients from the food.

The spleen opens at the mouth, and if the spleen function is normal, the appetite is good, the lips will be red and lustrous.

The taste of sweetness and worry will affect the spleen and the colour yellow relates to the spleen and influence the muscles and soft-tissue.


The sanjiao is not an organ but it has strong influence to the metabolic system. It is divided into 3 parts, hence its name – the upper, the middle and the lower portions. The upper portion represents the chest, its function is to transport the qi and blood to various organs. The middle portion is the epigastrium and umbilical regions. Its main function is to digest and absorb essential substances. The lower portion is the hypogastrium. Its main function is to excrete waste substances. The zang organ of the sanjiao is the pericardium and is responsive to the metabolic and lymphatic system.


The stomach is situated at the epigastrium. Its main function is to receive food, partially digest them and temporarily store them before sending them down to the small intestine. The qi of the stomach is a downward process. Its zang organ is the spleen and influence the muscles and soft-tissue system.


The pericardium is the outer covering the heart, and it protects the heart, at the same time influenced by the heart, liver and gall bladder. Its connecting fu meridian is the Sanjiao and the functions of the pericardium are similar to the heart.

Gall Bladder

The gall bladder is attached to the liver. Its main function is to store bile and help in digestion. The zang organ of the gall bladder is the liver and is responsive to the nail and tendon system.

Large Intestine

The large intestine is situated in the abdomen. Its main function is to transport waste substances from the small intestine to the anus to be excreted as faeces. In the process of transporting the waste substance, the large intestine also absorbs a part of its fluid content. Its zang organ is the lung and is responsive to the skin and hair system.

Small Intestine

The small intestine is situated in the abdomen, its main function is to further digest the food from the partially digested food in the stomach and absorb the essential substances and water from food and send the residues together with water to the large intestine, its zang organ is the heart. and is responsive to the brain and the vessel function.

Urinary Bladder

The urinary bladder is situated in the lower abdomen. Its main function is to store urine and discharge it when it has reached a certain amount. The zang organ of the urinary bladder is the kidney and is responsive to the bone and nerve system.

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