气

Qi, blood and body fluid, the essential substances for life activities, flow constantly inside the body and all originate from the viscera. They are produced by qi-transforming activities of the viscera and infused into the viscera to nourish the organs and tissues of the body.

Among the three, qi is the most active but invisible substance; blood and body fluid are visible, but must depend on the propelling action of qi to circulate in the whole body.

The basic concept of qi

The classic Chinese philosophy believes that the primary state of the universe is qi, the constant movement of which produces all the things in the universe, including life. Thus people in ancient China thought that the accumulation of qi would produce life while the dispersion of qi would put an end to life.

Qi is very active and in constant motion. Qi is also extremely fine and invisible.

Qi is the most essential substance that makes up the body and maintains life activities. All vital substances in the body are transformed by constant motion and change of qi. The viscera, the meridians, the five sensory organs, the nine orifices and the body itself are formed by the motion, transformation and accumulation of qi.

The production of qi

Qi exists right after the formation of individual life. This kind of qi is inherited from kidney-qi of the parents during pregnancy. So it is called "congenital qi" which is the foundation of the development of new life.

After birth, the human body keeps absorbing nutrients from the external world to nourish the congenital qi. This is the acquired source of qi, also known as "acquired qi". Acquired qi originates from food nutrients and fresh air inhaled into the body.

In fact, the "congenital qi"; and "acquired qi" are just two material sources of qi. The process of qi production also involves the other viscera. The inter-transformation among essence, qi, blood and body fluid influences the production of qi.

The physiological functions of qi

Qi is the essential substance that makes up the body and maintains various physiological activities. Qi in different viscera and organs functions differently. Generally speaking, there are five physiological functions of qi.

1. Propelling function

Qi is the motivation of the physiological functions of all the viscera and organs in the body. The propelling function of qi can stimulate and maintain the physiological functions of the viscera and other organs. That is why qi is called the root of life. Qi in different viscera and organs functions differently. For example, kidney-qi promotes the development of the body and reproduction, transform water and receive lung qi; heart-qi promotes blood circulation; lung-qi governs respiration and regulates water passage; spleen-qi promotes digestion and absorption of food and commands blood; liver-qi regulates various functions by smoothng the activity of qi. Weakness of qi in promotion will lead to hypofunction of the viscera and other organs and cause various deficiency problems.

2. Warming function

Qi warms the body and is the source of heat energy in the body. It is very important in maintaining normal body temperature and ensuring the physiological functions of all the viscera and organs. Since qi can warm the body, it is similar to yang in nature. So the kind of qi that warms the body is called "yang-qi";. All the five zang-organs have yang-qi respectively. For example, heart-yang warms and dredges blood vessels to promote blood circulation; lung-yang warms and nourishes skin and muscular interstices, preventing exogenous pathogenic factors from invading the body; spleen-yang warms and transforms food and water, promoting digestion and absorption; liver-yang steams and fumigates qi, promoting qi transformation in the five zang-organs and the six fu-organs; kidney-yang warms life-gate, stimulates reproduction and transforms water. If the warming function of qi is weakened, it will lead to stagnation of internal cold, unsmooth circulation of qi and blood and devitalization of the visceral functions.

3. Protecting function

Qi can protect the body, resisting the invasion of various pathogenic factors and preventing disease. As to pathogenic factors, the kind of qi that protects the body is called "healthy qi"; or "genuine qi". Healthy qi functions to protect the whole body against the invasion of pathogenic factors and, after the invasion of pathogenic factors into the body or onset of disease, to fight against the pathogenic factors to promote healing of disease. If the protecting function of qi is weakened, it mainly leads to decline of body resistance and susceptibility of the body to invasion of pathogenic factors.

4. Fixating function

Fixation of qi means that qi can astringe and control liquid substances, such as blood, body fluid and sperm, to prevent them from losing. To be specific, qi fixating blood means that qi keeps blood to flow inside the vessels and prevent it from flowing out of the vessels; qi fixating sweat, urine and saliva means that qi controls the secretion and excretion of these liquids so as to restrict the excretion and prevent loss; qi fixating sperm means that qi balances sex function and prevents seminal emission. Besides defecation and location of the viscera are under the influence of the fixating function of qi. If the fixating function of qi is weakened, it will lead to loss of blood, body fluid and sperm. The weakness of the qi fixation may also lead to protracted diarrhea, incontinence of urine and stool as well as proctoptosis and hysteroptosis.

5. Qi-transforming function

Qi-transformation means changes caused by the movement of qi, which is the essential cause of the conception, development, growth and decline of life. Life activities concerned with qi-transformation can be divided into three categories. Firstly, through food and respiration the body absorbs nutrients from the external world and transforms them into essence, qi, blood and body fluid essential to the body. Secondly, inter-promotion among the refined substances (essence, qi, blood and body fluid etc.) is the process of automatic regulation, improvement and balance of life. Thirdly, waste substance and turbid qi are excreted out of the body in the process of life. If qi-transformation is weakened, the whole process of life will be in disorder or decline, leading to various diseases. The declination of qi-transformation even leads to death.

The moving styles of qi

Movement of qi is known as qi activity. It includes four forms, i. e., ascending, descending, exiting and entering. Upward movement of qi means ascending while downward movement of qi means descending. Though ascending and descending are opposite, they can be transformed into each other. When qi ascends to the supreme point, it begins to descend. Such a transformation is known as "extreme ascending changes into descending". When qi descends to the lowest point, it begins to ascend. Such a transformation is known as "extreme descending turns into ascending";. This is the upward and downward movement of qi under normal conditions.

Coming in and going out, two opposite moving styles of qi, take place alternately. When qi disperses outward (going out) to a certain degree, it begins to restrain itself inward (coming in). When qi restrains itself inward(coming in) to a certain degree, it begins to disperse outward (going out). This is the external and internal movement of qi under normal conditions.

Ascending and descending, coming in and going out are two types of the motion of yin and yang, which coordinate with each other. For example, the activities of ascending and going out pertain to yang; the activities of descending and coming in pertain to yin. So ascending coordinates with going out while descending coordinates with coming in.

The ascending, descending, coming in and going out activities of qi are accomplished by the viscera and meridians. Each zang-organ or fu-organ may differ from others in the moving style of qi. For example, liver-qi is ascending, lung-qi is descending, spleen-qi is ascending and stomach-qi is descending, etc. The zang-organs and the fu-organs, though different from each other in the moving styles of qi, coordinate with each other and form a special system for regulating qi activity. For example, the liver and the lung restrict but coordinate with each other in ascending and descending; the spleen and the stomach associate and cooperate with each other in ascending and descending, etc. The meridians and collaterals are the important routes for qi to flow. With the different running directions of the meridians, the ascending and descending activities of qi also become different. The meridians of the viscera run from the internal to the external, qi in these meridians flows outward accordingly. If the meridians run from the external to the internal of the body, qi in these meridians will flow from the external to the internal. If the meridians run from the head to the lower part of the body, qi in these meridians will accordingly flow from the upper to the lower. If the meridians run from the feet upward, qi in these meridians will certainly flow upward.

The ascending, descending, coming in and going out activities of qi are very important to life. If these activities of qi are normal, the functions of the viscera and the meridians will be normal. If these activities are abnormal, the functions of the viscera and meridians will be in disorder. If these activities of qi stop, death will occur.

The classification of qi and its production, distribution and functional characteristics

There are various classifications and names of qi. Usually qi is classified into yuan-qi ( the primordial qi), zong-qi (the pectoral qi), ying-qi (the nutrient qi) and wei-qi ( the defensive qi).

Yuan-qi (primordial qi)

The primordial qi, also called primary qi or genuine qi, is the most essential qi in the body and the vital foundation of life.

1. The production of the primordial qi
   The primordial qi mainly comes from kidney-qi of the parents during pregnancy. That is why TCM usually calls the primordial qi "the congenital qi". The power and quantity of the primordial qi are already fixed after birth. However, after birth the primordial qi still needs further nourishment and enrichment to enable it to be distributed to the whole body and to exert normal physiological effect. The primordial qi transformed from food nutrients provided by the spleen and stomach is called "acquired qi".

2. The distribution of the primordial qi
   The primordial qi is stored in the kidney and distributed to all parts of the body through the triple energizer. The primordial qi transformed from food nutrients provided by the spleen and stomach must be stored in the kidney so that it can be distributed to the whole body. Though the primordial qi is distributed to all parts of the body, it originates from the kidney.

3. The functional characteristics of the primordial qi
   The primordial qi shares the common functions of qi, such as propelling, warming, protecting, fixating and qi-transforming, etc. The functions of the primordial qi are different if its location is different. The characteristics of the primordial qi in the kidney include three aspects: to promote the growth and development of the body and maintain reproductive functions of the body; to promote qi transformation to regulate water metabolism and excretion of urine; to fixate sperm and inhaled fresh air to ensure the functions of the kidney to store essence and receive qi. The primordial qi distributed to all parts of the body warms and promotes all the viscera so as to bring their physiological functions into full play. For example, the spleen governs transportation and transformation; the lung governs respiration; the heart dominates blood; the liver controls dredging and dispersing; the stomach is responsible for reception ancl digestion, etc. These are all the concrete manifestations of the effect of the primordial qi on the viscera. Thus the primordial qi is the vital qi in the body and is the motivation of all life activities. The state of the primordial qi decides the state of life.

Zong-qi (the pectoral qi)

The pectoral qi is a kind of essential qi in the body. Since it is produced after birth, it is a kind of acquired essential qi. The pectoral qi accumulates in the chest. When transported from the chest, it is divided into ying-qi ( the nutrient qi) and wei-qi (the defensive qi) which are distributed to the whole body.

1. The production of the pectoral qi
   The pectoral qi is produced by combining the fresh air inhaled by the lung with the food nutrients absorbed and transported by the spleen. The respiratory function of the lung and the transporting and transforming functions of the spleen influence the production of the pectoral qi.

2. The distribution of the pectoral qi
   Since the pectoral qi accumulates in the chest, the chest is called "the sea of qi". Because the heart and the lung are located in the chest, the pectoral qi infuses into the heart and the lung and flows in the vessels and respiratory tract. So the state of the pectoral qi influences the functions of the heart vessels, the lung and the respiratory tract.

3. The functinal characteristics of the pectoral qi
   The pectoral qi has two functions. One is to warm and nourish the heart vessels to maintain their functions in transporting qi and blood. The other is to warm and nourish the lung and the upper respiratory tract to maintain their functions in governing respiration and vocalization. If the pectoral qi is insufficient, it will lead to palpitation, shortness of breath and weak voice, etc.

Ying-qi (nutrient qi) and wei-qi (defensive qi)

The nutrient qi and the defensive qi all come from the pectoral qi and are closely related to each other in production and circulation. The nutrient qi pertains to yin and the defensive qi pertains to yang. So the nutrient qi and the defensive qi are also called ying-yin (nutrient yin) and wei-yang (defensive yang).

1. the production ot the nutrient qi and the defensive qi
   Both the nutrient qi and the defensive qi come from the pectoral qi. The pectoral qi flows to the whole body from the chest in the form of the nutrient qi and the defensive qi. In terms of the production, the nutrient qi and the defensive qi, just like the pectoral qi, is produced by combining the fresh air inhaled by the lung with the food nutrients absorbed and transported by the spleen. The only difference lies in food nutrients. The nutrient qi comes from the "most essential part" of the food nutrients while the defensive qi comes from "the most active and powerful part" of the food nutrients.

2. The distribution of the nutrient qi and the defensive qi
   The nutrient qi and the defensive qi are different in nature. The former, pertaining to yin in nature, flows inside the vessels while the latter, pertaining to yin in nature, flows outside the vessels. That also explains why the nutrient qi distributes in the internal organs while the defensive qi distributes over the surface of the body. Certainly there is the defensive qi in the internal organs and there is the nutrient qi in the superficies. But the nutrient qi mainly flows inside the internal organs and the defensive qi mainly circulates in the superficies.

3. The functional characteristics of the nutrient qi and the defensive qi
   The nutrient qi and the defensive qi are different from each other in functional characteristics. The functional characteristics of the nutrient qi are marked by transformation into blood to nourish the whole body, especially nourishing the internal organs to maintain their physiological functions. The functional characteristics of the defensive qi are marked by warming and nourishing the body and protecting the body against pathogenic factors, especially warming and nourishing the muscles and superficies as well as regulating sweat so as to protect the body against pathogenic factors. The defensive qi pertains to yang. That is why it can warm the body. But it regulates sweat to excrete excessive yang-heat so as to maintain a constant body temperature.