TCM Organ System or Zang Fu

The Zàng-Fǔ organs are functional entities stipulated by Traditional Chinese medicine (TCM). They constitute the centrepiece of TCM’s general concept of how the human body works.

The term zàng (脏) refers to the organs considered to be yin in nature – Heart, Liver, Spleen, Lung, Kidney – while fǔ (腑) refers to the yang organs – Small Intestine, Large Intestine, Gall Bladder, Urinary Bladder, Stomach and Sānjiaō.

Zang Fu (Internal Organs)

Zang Organs (Yin)

Fu Organs (Yang)

Large Intestine
Small Intestine
Urinary Bladder
San Jiao
Gall Bladder

The Internal Organs are paired as Yin (internal organ) and Yang
(external organ)
Lungs paired with Large Intestine ; Spleen paired with Stomach; Heart paired with Small Intestine; Kidneys paired with Urinary Bladder; Liver paired with Gall Bladder; Pericardium paired with San Jiao


The Pericardium and San Jiao are paired together.

The Pericardium

Functions of the Pericardium

The Heart Protector or Heart Governor

It is the outer membrane around the heart that protects it from attacks by exogenous pathogenic factors.

The pericardium is capable of being attacked by exogenous Heat, but the Heart is not (directly).

In TCM theory and herbology, this is the only way the Pericardium is usually distinguished from the Heart.

In Acupuncture however, the Pericardium has it’s own meridian and is just as important as the heart Channel itself. Many points on the Pericardium Channel are used to treat the Heart, and many strongly influence the mental state.

Pericardium influences relationships with other people: Points on its channel are often used to treat emotional problems from relationship issues.

Pericardium channel particularly influences the area in the centre of the thorax.


San jiao

The San Jiao as a Yang organ:

· “The San Jiao is the official in charge of irrigation and it controls the water passages.” (Simple Questions).

In this thought, the San Jiao has form like all the other organs.

It helps to receive food, digest it, transform and transport it, and excrete the wastes.

The San Jiao moves fluids in the upper Jiao through the defensive Qi, through the mid Jiao as nutritive Qi, and through the low Jiao as body fluids.

The ability of the Stomach, Lungs, and Kidneys and Bladder to disperse their fluids is dependant on the San Jiao.

Therefore malfunction of the San Jiao can Manifest in blockage of the upper, mid, or low Jiao.

This can cause sneezing, abdominal distension, and retention of urine.

The San Jiao is where the Yuan Qi flows:

In this theory, the San Jiao has no form, it is not an organ, it is a collection of functions.

The Classic of Difficulties says that the Yuan Qi resides between the Kidneys and spreads to the Zang Fu via the San Jiao, it then enters the twelve meridians and emerges at the Yuan-source points.

The Yuan Qi can only make possible all body functions through its spreading by the San Jiao. Therefore it greatly effects the warming for digestion, and excretion.

The San Jiao as three divisions of the body:

This theory comes from both the Spiritual Axis and The Classic of Difficulties.

1. The upper Jiao is from the diaphragm up (Heart, Lungs, Pericardium, throat and head),

2. The mid Jiao is from the diaphragm to the umbilicus (Stomach, Spleen, and Gallbladder), and

3. The area below the umbilicus is the low Jiao (Liver, Kidneys, Intestines, and Bladder).

  • Upper Jiao: distributes the fluids in a mist-like form all over the body through the use of the Lungs.
  • Mid Jiao: digests and transports the essential nourishment from food and drink to the whole body.
  • Low Jiao: separates the essences from the dirty in our foods and fluids. This functions ensures excretion of urine.


The Internal Organ Relationships

Heart and Lungs
Heart and Liver
Heart and Kidneys
Liver and Lungs
Liver and Spleen Liver and Kidneys
Spleen and Lungs
Spleen and Kidneys
Lungs and Kidneys
Spleen and Heart

Heart and Lungs

Heart governs Blood, Lungs govern Qi: relationship is that of Qi and Blood.

Qi and Blood are interdependent. Blood nourishes Qi but Qi pushes the Blood.

Heart moves the Blood but relies on Lung Qi to assist.

Lungs produce Ying (and Wei) Qi. Ying Qi flows with the Blood in the Vessels.

Heart and Lung connect via the Zong Qi (Chi of the Chest)

Deficient Lung Qi can lead to stagnation of Qi in the Heart and this can lead to stagnation of Blood of the Heart, with symptoms such as palpitations, chest pain, blue lips.

Excessive Heart Fire can dry up Lung fluids and cause dry cough, dry nose and thirst.

In practice, Heart and Lung Qi are often deficient at the same time because of their close relationship.

Sadness often depletes both Lung and Heart Qi.

Heart and Liver

The heart and the Liver are related via Blood.

Heart governs Blood, Liver stores Blood and regulates its volume. These two activities must be coordinated and harmonized. If Heart Blood is deficient, this may disrupt Liver’s ability to regulate Blood (dizziness, excessive dreaming).

Deficient Liver Blood can cause Deficient Heart Blood (palpitations and insomnia).

Heart stores Shen and Liver rules smooth flowing of the emotions.

Shen and emotions mutually support each other. Weak Heart and Shen may lead to depression and anxiety. Or, when Liver Qi stagnates, this constrains emotions and can weaken the Shen.

Heart and Kidney

Mutual assistance of Fire and Water.

Heart belongs to Fire element and is in Upper Burner. (Fire is Yang and corresponds to movement).

Kidneys belong to Water element and are in Lower Burner. (Water is Yin and corresponds to stillness).

Heart & Kidney must be in balance as they represent two fundamental polarities of Yang and Yin (Fire & Water).

Heart Yang descends to warm Kidney Yin while Kidney Yin ascends to nourish Heart Yang. This constant interchange is referred to as “mutual support of Fire and Water”.

Kidney Yang Deficient:
Kidneys cannot transform fluids; these can overflow upward to Heart.

Kidney Yin Deficient:
Yin cannot rise to nourish Heart Yin.

This can cause overactive Heart Fire (mental restlessness, insomnia, agitation, etc.)

Both these situations represent loss of communication between Heart and Kidney.

Heart and Kidneys are Common Root of Shen and Essence (Jing). The Heart houses Shen, while the Kidneys store Jing.

Shen and Jing have common root. Jing is fundamental substance from which Shen is derived, in other words, Shen is external manifestation of Jing.

Prenatal Jing is the foundation of the Shen, Postnatal Jing provides nourishment for the Shen.

Normal mental activity needs good supply of Jing.

Weak Jing results in a weak Shen and the person will lack vitality, willpower, self confidence.

When Shen is disturbed by emotional problems, Jing will not be directed by the Shen and the person will feel tired and lack motivation.

Liver and Lungs

Reflects the relationship of Qi and Blood.

Lungs govern Qi, and the Liver regulates and stores the Blood.

They rely on each other in that the Liver relies on Lung Qi to regulate Blood, and the Lungs rely on Liver Qi to smoothly move Qi.

Deficient Lung Qi can affect Liver’s smooth movement of Qi (fatigue, depression, cough and hypochondriac pain).

Liver Qi can stagnate in the chest and interfere with the Lung’s function of descending (cough, dyspnea, asthma).

Stagnation of Liver Qi can cause Liver Fire to rise and injure Lung Yin (Hypochondriac pain, coughing blood, pain on breathing).

Liver and Spleen
When healthy, Liver Qi aids Spleen in digestion, and ensures smooth flow of bile to aid digestion.

By ensuring smooth flow of Qi in all directions of the body, Liver ensures that Spleen Qi flows upwards in its right direction.

Stagnant Liver Qi disrupts Spleen ability to transform and transport food and fluids and to “raise the pure”. (abdominal distension, hypochondriac pain, diarrhoea).

Liver and Kidneys

Based on mutual exchange between Blood and Jing.

Kidney Jing contributes to the making of Blood. (Jing produces bone marrow which is connected with manufacture of Blood in the body).

“Liver and Kidneys have a common origin”.

“Essence and Blood have a common source”.

Kidney Yin nourishes Liver Yin (including Liver Blood).

Deficient Kidney Jing may lead to Blood becoming Deficient (dizziness, blurred vision, tinnitus).

Kidney Yin fails to nourish Liver Yin, causing hyperactivity of Liver Yang (blurred vision, tinnitus, headaches, irritability, dizziness.

Spleen and Lungs

Mutually assist each other.

Spleen extracts Food Qi and sends it up to the Lungs where it combines with air to form Zong Qi.

Spleen relies on Lung descending function to assist in the transformation and transportation of food (diaphragm movement helps Middle burner – “pumping” action).

Lung descending function also assists Spleen in the transformation of Body Fluids. Lung Qi weak, descending function impaired, Spleen cannot transform and transport the fluids, causing edema.

Deficient Spleen Qi: Food Qi deficient and production of Qi impaired (especially of Lung Qi: tiredness, weak limbs, breathlessness, weak voice) (Earth not producing Metal).

Spleen Deficiency: fluids not transformed but accumulate to form Phlegm, which settles in Lungs and impairs Lung function. “The Spleen forms Phlegm, the Lungs store it.”

Spleen and Kidneys

Relationship is one of mutual nourishment.

Spleen: Root of Post-Heaven Qi (Foundation of Postnatal Existence)

Kidneys: Root of Pre-Heaven Qi (Foundation of Prenatal Existence)

The Postnatal Essence (Postnatal Jing) is formed from the food we eat and the air we breathe. The Spleen therefore plays the most important role in the formation of Postnatal Essence.

The Postnatal Essence is stored in the Kidneys together with the Prenatal Essence. Where Spleen Qi is weak, Postnatal Essence will not be produced as effectively, and the Kidney will have less Postnatal Essence to store.

Prenatal Essence assists in the production of Qi via its active aspect (Original Qi): the Original Qi provides the necessary energy for the transformation and transportation of the substances and formation of Qi: this affects the Spleen’s function.

Spleen and Kidneys support one another regarding transformation/transportation of Body Fluids.

Where Spleen Qi is weak, and Body Fluids are not able to be transformed and transported, these accumulate to form Dampness, which can interfere with the Kidney’s function regarding fluid metabolism (which then makes the Dampness worse).

Where Kidney Yang is Deficient, there is not enough heat for the Spleen to transform Fluids: this can cause Dampness or oedema, chilliness and diarrhoea.

Lungs and Kidneys

Important relationship with regard to Qi and Fluids


Lungs send Qi and Fluids down to the Kidneys. Kidneys hold down the Qi and evaporate some of the Fluids, then send fluid vapor back to the Lungs to moisten them and the Lung then sends Fluids to moisten the skin.

Lungs send Qi down the Kidney and Kidneys hold down the Qi. Therefore they have an important communication regarding respiration

Communication regarding Zong Qi and Original Qi.

Zong Qi (in the chest) flows down to connect with the Original Qi from which it is nourished. Original Qi flows up to the chest to assist with the production of Qi and Blood in the Upper Burner.

The Lung function of governing Qi and respiration depends on the Kidney function of receiving Qi.

Where Kidney energy is weak: impaired reception of Qi. Kidneys fail to hold Qi down and Qi flows back up to the chest (“rebels”) and obstructs the Lung’s descending function. Result is asthma, cough and dyspnea (unable to inhale deeply).


Lungs control Water passages and send Fluids down to the Kidneys. Kidneys evaporate some fluids and send them back up to the Lungs to keep Lungs moist. “Kidneys govern Water and the Lungs are the upper origin of Water.”

Deficient Lung Qi: Lung cannot send fluids downwards and Lung cannot communicate with Kidneys and Bladder (edema, especially of upper body).

Deficient Kidney Yang: Kidneys cannot transform and excrete Fluids in the Lower Burner. These Fluids then accumulate to form Dampness or edema (especially of lower body). Because of the close relationship of Lungs and Kidneys regarding fluid metabolism, this accumulation of Fluids can eventually affect the Lung and impair Lung’s descending and dispersing function.

Deficient Kidney Yin: leads to deficiency to Fluids in the Lower Burner. Fluids fail to rise to moisten the Lungs, causing Deficiency of Lung Yin (dry throat at night, dry cough, night sweats and feeling of heat in the palms and soles of the feet).

Deficient Lung Yin (can arise from smoking, or after a long febrile disease involving the Lungs). This implies Deficient Fluids in the Lungs, inability of Lungs to send Fluids to Kidneys, which then results in Deficient Kidney Yin. (Smokers usually end up with depleted Kidney Yin as a result of this mechanism).

Spleen and Heart
Interrelated via the Blood.

Spleen provides Food Qi for the formation of Blood.

Deficient Spleen Qi can lead to Deficient Blood, which can cause Heart Blood to be Deficient (resulting in palpitations, dizziness, poor memory, insomnia).

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