In TCM books, qi is always mentioned in the same breath with blood and body fluid, for they are all the fundamental substances constituting the human body and maintaining its life activities. However, among them qi is particularly important for the human body. That is why TCM often explains the life activities of the human body in the viewpoint of qi. For this reason, ZhangJingyue said: "Man's life relies entirely upon this qi." Classic onMedical Problems states:"qi is ihe root of the human body; once the root is damaged, the stem and leaves would turn withered". And, also, Basic Questions points out : "One's life is the combination of qi of heaven and earth".|
Qi in the human body is composed of congenital qi and acquired qi. The former is inherited from one's parents before birth,the latter is derived from cereal essence transformed by the spleen and stomach and fresh air inhaled from the natural world by the lung. Therefore, qi is a combination of three kinds of factors. It is easy to see that the source or production of qi is related to innate endowment, acquired nutrition and environmental conditions, and the actions of the kidney, spleen, stomach, lung as well.
Congenital qi and acquired qi complement each other. Congenital qi is the material foundation for the production of acquired qi, and acquired qi continuously supplements congenital qi with nourishments. Both of them are, therefore, described as an interdependent relation-congenital qi promoting acquired qi,which, in turn, nourishing congenital qi. There are all kinds of qi and, their functions are too intricate to be expounded in a few words .To provide a precise exposition, let's discuss them under six heads.
1 . Promoting Action of Qi 1.气的推动功能
Qi, as a sort of refined substance full of vigour, plays a promoting and activating role in the growth and development of the human body, the physiological activities of the zang-fu organs and meridians, the production and circulation of blood, as well as the production, distribution and excretion of body fluid. If the above functions are weakened due to qi-deficiency, the following pathologic changes will occur: tardy growth and development of the human body, hypofunction of the zang-fu organs and meridians, stagnation of blood, fluid retention, etc.
2. Warming Action of Qi 2.气的温煦功能
Whether man's body temperature is normal or not depends on the warming action of qi. Classic on Medical Problerns says:" Qi is responsible for warming." Only through the warming action of qi can all zang-fu organs，meridiarns and other structures perform their normal functional activities, and can such liquid substances as blood and body fluid circulate normally. As the saying goes: " Blood flows in warmth, while it coagulates in cold."For example, the insufficiency of yang-qi may impair the warming action of qi, causing an aversion to cold, cold limbs. Lowered body temperature and so on. Conversely, qi excess may result in the failure of qi to disperse heat, marked by preference for cold, fever, etc. Basic Questions states, "Qi excess preduces heat, while qi deficiency produces cold."
3. Defending Action of Qi 3.气的防御功能
Qi has defending function to defend the body surface against the exogenous pathogens and to combat with the invaded exogenous pathogens to drive them out of the body. The book Basic Questions, therefore, states:" When vital qi exists in the body, the exogenous pathogens can not attack the body." And " If the pathogens invade and occupy the body, qi-deficiency is bound to ensue." Thereby leading to illness.
4. Controlling Action of Qi 4.气的固摄功能
Qi also has controlling action, by which is meant the ability to control the liquid substances and fix the internal organs in the body. This is shown in the following aspects:
(1) Keeping the blood flowing within the vessels to prevent it from extravasating without reason.
(2) Controlling and regulating the secretion and excretion of sweat, urine, sperm, saliva, gastrointestinal juices, etc , to maintain a relative balance of water metabolism.
(3) Firming the internal organs in their normal positions without prolapse.
If this action is impaired, hemorrhage, premature ejaculation, spontaneous sweating, urinary incontinence, and spermatorrhea will occur. If this action fails to work normally,such prolapses as gastroptosis, nephroptosis, hysteroptosis will be brought about.
The promoting and controlling actions of qi are the two aspects of mutual opposition and mutual complement. Provided these two actions work harmoniously, blood circulation and water metabolism can be normally carried on.
5 . Action of Qi Transformation
Qi transformation may be defined as various kinds of changes brought about by the movement of qi. Concretely speaking, it refers to the respective metabolism of essence, qi, blood and body fluid and their reciprocal transformation. For instance, food is transformed into qi, blood and body fluid; body fluid are converted into sweat and urine by metabolizing, and the residues of food,after digestion and absorption, are turned into feces to be discharged from the body. All these processes are all the specific manifeatations of the action of qi transformation. If qi transformation is out of order, it will affect the digestion, absorpiion of food, the metabolism and transformation of essence, blood and body fluid, the excretion of sweat, urine and feces and so on .To put it briefly, qi transformation is actually the process in which the substances in the body are metabolized and intertransformed. Although the above five actions of qi differ from one another, they are indispensable to maintaining human life. Their harmonious cooperation and mutual support ensure that the physiological activities are completed smoothly.
The Movement of Qi is known as "qi ji", qi activity. Qi in the human body travels throughout the body and reach all the zang-fu organs and meridians to promote and activate the physiological activities of the human body.
Qi has four basic forms: ascending, descending, exiting and entering. These four forms are the basis of human's life activities.Once these movements stop, it means that the life activities ceaseand death ensues.
The ascending, descending, exiting and entering of qi are mainly embodied in the physiological activities of the zang-fu organs, meridians and other processes of metabolism. For example,the lung governs respiration, exhaling pertains to exiting, inhaling to entering; and dispersing pertains to ascending, lowering to descending. The spleen sends the clear upward and the stomach passes the turbid downward. So all kinds of physiological activities in the human body, essentially, are reflected in the four movements of qi.
According to the sources, functions and distributions, qi is divided into four types: primordial ( yuan qi), genuine qi (zhenqi) , pectoral qi (zong qi) , nutritive qi( ying qi) and defensive qi(wei ai) .
l . Primordial qi, also known as genuine qi (zhen qi) is the most important of the four kinds of qi. It is the primary motive force of life activities. Primordial qi derives from the congenital essence stored in the kidney, and depends on the acquired essence regenerated by the spleen and stomach. The book Miraculous Pivot makes it clear by saying, "Genuine qi (Zhen qi) is inherited from heaven ( the parents) and combined with cereal essence to replenish the body." 1.元气，也叫做真气是四种气中最重要的一种。它是人体活动的原动力。元气源于先天之精，储藏于肾中，依赖脾胃化生的后天之精滋养。《灵枢》中明确说：“真气者，所受于天，与谷气并而充身者也.。”
2. Pectoral qi is formed from a combination of the fresh air inhaled by the lung and the cereal essence conveyed by the spleen and stornach. Pectoral qi performs two main functions. One is traveling through the respiratory tract to prormote respiration and the sufficiency or insufficiency of pectoral qi influences the conditions the voice. speech or breath and so on. The other is running through the heart-meridians to promote the circulation of qi and blood. The vicissitude of Pectoral qi is related to the flow of qi and blood, the body temperature and the activities of the trunk and limbs, the visual and aural perceptibility, as well as the strength and rhythm of the heart beat. 2.宗气由肺吸入的清气和脾胃化生的谷气混合而成。宗气主要执行两种功能。一种是走息道以行呼吸,宗气的充足与否会影响到声音、言语和呼吸的状态。另一种是贯心脉以行气血,宗气的充足与否与气血的运行、体温、四肢活动、视觉、听觉能力以及心脏搏动的力量和节律有关。
3.Nutritive qi is the qi that circulates together with blood in the vessels. Nutritive qi originates from the pure part of cereal essence transformed by the spleen and stomach and bears responsibility for the blood production and the nutrition of the whole body. Nutritive qi is considered as yin, so it is also called nutritive yin ( ying-yin) . 3.营气是与血共同运行脉中的气。营气源于脾胃运化的水谷精微的纯净部分，并承担着血液的产生和濡养全身的职责。营气属于阴，所以也称作营阴。
4 . Defensive qi, like nutritive qi, comes from cereal essence,but, unlike nutritive qi, it runs outside the blood vessels. Defensive qi has the following functions: protecting the body surface against exogenous pathogens, controlling the opening and closing of the pores, adjusting the excretion of sweat, warming and nourishing the zang-fu organs. muscles and the skin with hairs, etc.,maintaining a relatively constant body temperature. It is given the name "defensive qi" precisely because of its antiexogenouspathogenic action. Defensive qi belongs to yang, so it has another name defensive yang ( wei-yang) ," which presents a strinking contrast with ying-yin as mentioned above. 4.卫气，如营气一般，来自水谷精微，但是却行于脉外，这与营气不同。卫气有以下功能：保护体表免受外邪侵犯，司毛孔的开合，调节汗液排泄，温养脏腑组织、肌肤毛发等和维持体温的恒定。“卫气”这一名字正是因为它有抗御外邪的功能。卫气属阳，所以别名叫“卫阳”,这正好与以上提及的营阴形成鲜明的对比。
THE TYPES OF QI AND THEIR MOVEMENTS
Types of Qi
Yuan Qi(Primordial Qi) starting from between the two kidneys, passing through tri-energizer and circulating through the while body, inward to zang- and fu-organs and outward to the muscles and skin. 元气
Zong Qi(Pectoral Qi) stored in the chest and poured into the meridians of the heart and the lung. 宗气
Ying Qi(Nutritive Qi) originating from tri-energizer, entering the meridians by way of the lung, and circulating all over the body. 营气
Wei Qi(Defensive Qi circulating outside but leaning against the meridians, vaporized to the diaphragm and scattered in the chest, travelling between the skin and flesh. 卫气
Special phrases 特殊短语
As the saying goes, As=in the way that，as the story goes/runs 或云；相传
as the matter stands 照目前情形
as the case may be 依照情况
as things are 照此情况
as things run 照通常顺序、情形、性质等