The five Zang organs are responsible for storage and are considered Yin. The Fu organs are part of the digestive system, representing Yang. Within this framework, the Yin Wood corresponds to the liver (Gan), while the Yang Wood corresponds to the gallbladder (Dan). The Yin Fire is associated with the heart (Xin), and the Yang Fire corresponds to the small intestine (Xiao Chang). Fire has two components: the heart and the small intestine. The spleen (Pi) represents Yin Earth, while the stomach (Wei) represents Yang Earth. The lungs (Fei) are Yin organs, while the large intestine (Da Chang) represents Yang. Water is categorized into Yin Water and Yang Water. When discussing the Zang organs, we refer to Yin, while for the Fu organs, we refer to Yang. Therefore, the kidneys (Shen) are Yin, and the Yang Water corresponds to the bladder (Pang Guang). The codes have their significance; let me illustrate with an example. Why does Traditional Chinese Medicine (TCM) define the heart as fire? Because the heart continuously beats, generating heat, which Western medicine does not recognize in the same way. Western medicine focuses on structural issues, such as valve insufficiency, arrhythmias, myocardial infarction, and arterial sclerosis, only seeing the form without understanding the essence. It may seem detailed, but it lacks the spirit. The heart’s continuous beating, approximately over 100,000 times a day, generates heat. If it is hot, we can only describe it as “fire,” right? Therefore, the source of body temperature comes from the heart, as the heart’s continuous beating regulates the entire body. Western medicine may know the temperature in Fahrenheit (98 degrees), but it does not understand how it is generated; it comes from the heart. The small intestine is considered Yang Fire because it is part of the digestive system. Food enters the stomach and then the small intestine, where it is digested. Why is the small intestine also defined as fire? Because the heart and small intestine are interrelated, a relationship we call the “interior-exterior relationship.” In TCM, the exterior refers to the Fu organs, while the interior refers to the Zang organs. Both the heart and small intestine are defined as fire, with the small intestine acting as the second heart. The heat generated by the heart should ideally rise, similar to how hot air balloons rise. Therefore, heat naturally ascends, but if it rises too much, it can lead to overheating, resulting in fever. The brain could be damaged! Thus, the lungs were created; they represent metal in the Five Elements. In the Yin-Yang and Five Elements theory, fire overcomes metal, creating a balance between the two. The lungs are like the sky, which is cold. If we consider the heart as the engine, the lungs act as the radiator. If the lungs only function for breathing, that would be too simplistic! You need to understand the balance between the lungs and the heart. Under normal conditions, the lungs help to lower heat, and practitioners of Qi Gong guide Qi downwards, with the Dantian being the small intestine’s Mu point, allowing Qi to descend. Thus, the temperature of the small intestine becomes very hot. The original source of heat comes from the heart. What does it mean to be a normal person? In clinical practice, I often ask patients, “Who told you that you have liver disease?” The answer is often a liver disease specialist. External signs are often from specialists, while I am a health doctor. TCM and Western medicine are opposites; Western medicine complicates diseases, while TCM seeks to understand what a normal person is. If you are trained to look for diseases, you may search for a long time without finding a solution. If you are trained by me, you will know what is abnormal at a glance! TCM does not require you to read many books; rather, you need to “understand”—that is the most important! I aim to help you understand what a normal person is.
The fire from the heart directs downwards to the small intestine, so in a normal person, the heart and small intestine operate at the same speed, temperature, and pressure. Therefore, TCM is a form of physical medicine. Einstein was a master of physics, yet he never went to space. The moon landing was accomplished by Armstrong, right? His office was small, and with just a blackboard and chalk, he could calculate black holes based on data received from NASA, proving Einstein was correct. TCM is also a form of physical medicine, emphasizing time, speed, temperature, and pressure. He never went to a black hole but could calculate it. TCM operates based on time, speed, temperature, and pressure; your body is a small universe. This is TCM, allowing one to see the inside from the outside. The small intestine generates heat, allowing food to be digested. The small intestine is quite intelligent, capable of digesting food. If you remove the small intestine, it will not digest food; without heat, it cannot function. This is how a normal person operates. Therefore, the small intestine is defined as fire. After digestion, food enters the large intestine, which absorbs the water from the food. Try eating pig intestines; can the large intestine intelligently absorb the water from the food? The large intestine surrounds the small intestine; the small intestine is fire, and water flows above it, while fire burns below. The heat from the large intestine vaporizes the water, allowing the vapor to rise through the intestinal wall. The large intestine and lungs are interrelated; the water returns to the lungs, becoming normal body fluids, while the waste is expelled. This process must be completed within twenty-four hours; this is a basic concept. As we delve deeper into the “Huangdi Neijing,” we will explore these concepts further. Why can TCM treat cancer? It is simple. You have heard of people dying from breast cancer, lung cancer, lymphatic cancer, and liver cancer, but have you ever heard of someone dying from heart cancer? People die from heart disease, not heart cancer. The heart does not get cancer because it is very hot; cancer cells passing through the heart are like moths to a flame. If the entire body were as hot as the heart, cancer cells would cease to exist. The human body is hot; how can we prove this? In winter, if you exhale and it is not white vapor, then you are an alien, not from Earth. Everyone has Qi, and Qi is hot. In TCM, the concept of hot Qi is vapor. This is a simple example. For instance, water nourishes wood; the bladder is in front of the small intestine, with the bladder here and the small intestine there, where the kidneys first vaporize, and the small intestine is the second vaporization. After the “Huangdi Neijing,” we will discuss this in more detail. The small intestine is very hot; when the bladder has 400cc of urine, it expands, and the bladder becomes a hot air balloon rising. When it is not filled to 400cc, we do not feel the urge to urinate. Once it reaches 400cc, we urgently need to go to the bathroom. When urine is expelled, the heat from the bladder generates speed, force, and pressure to expel the urine. The vaporization process in the bladder is the first distillation, while the second vaporization expels the turbid water. The clean water is sent to the liver, which receives the clean water (water nourishes wood) to eliminate toxins, which are then sent to the gallbladder to be transformed into bile.
The human body is complex; if we do not use this diagram to represent it, there is no other diagram that can do so. After discussing such complexity, we can simplify it to the point of no further simplification. In reality, it cannot be replaced; we must use this symbol to represent it. The heart, one of the five Zang organs, is located in the left side of the thoracic cavity, above the diaphragm and below the lungs, round and pointed downwards, resembling a lotus bud, protected by the pericardium. The heart, small intestine, pulse, face, tongue, and other components form the heart system. The heart belongs to the fire element in the Five Elements, being the Yang among the Yang organs, governing blood vessels, housing the spirit, and being the master of the Zang and Fu organs, as well as the ruler of life. The heart corresponds to the summer season. The physiological functions of the heart include: 1. The heart governs blood vessels, meaning it has the role of managing blood and promoting blood circulation in the vessels, including both governing blood and governing vessels. Blood refers to blood, while vessels refer to the channels, also known as meridians, which are the pathways for blood circulation. The heart is connected to the vessels, forming a closed system that serves as the hub of blood circulation. The heart’s rhythmic beating requires three conditions: abundant heart Qi, sufficient blood, and unobstructed vessels. 2. The heart houses the spirit. The meaning of spirit in TCM has three aspects: first, it refers to the functions and laws of material movement and change in nature. The saying “Yin and Yang are unpredictable, referred to as spirit” (from the “Suwen: Tian Yuan Ji Da Lun”). Second, it refers to the totality of life activities in the human body, generally called the broad sense of spirit. The external manifestations of life activities, such as the overall appearance of the body, complexion, eye expression, speech, responses, and body movements, all fall within the scope of spirit. In other words, all external manifestations of the body are reflections of life activities. Third, it refers to people’s mental, conscious, and cognitive activities, generally called the narrow sense of spirit. Essence and Qi are the material basis for producing spirit. The physiological functions of the heart in housing the spirit have two aspects: first, it governs thinking, consciousness, and spirit. Under normal conditions, the clear heart receives and reflects objective external things, engaging in mental, conscious, and cognitive activities. Second, it governs life activities. “The heart is the ruler of the body, the root of all things” (from the “Yinshan Zhengyao: Preface”). The clear heart governs life activities. The Zang and Fu organs must operate under the unified command of the heart to conduct coordinated and normal life activities. The heart is the monarch, and all organs and tissues obey the heart. The heart houses the spirit and serves the purpose of the spirit. “The heart is the great master of the Zang and Fu organs, the dwelling place of the spirit” (from the “Ling Shu: Xie Ke”). The physiological characteristics of the heart: the heart is a Yang organ and governs clarity. The heart is the sun among the Yang organs, utilizing Yang Qi. The Yang heat of the heart not only maintains the physiological functions of the heart itself but also nourishes the entire body. The relationship between the heart and form, orifices, will, fluids, and time: the heart is connected to the pulse, and its manifestation is in the face. The heart is associated with the tongue. The heart corresponds to joy in emotions. The heart is related to sweat in fluids. The heart corresponds to summer heat. The heart externally corresponds to the chest. “The heart is the official of the monarch, and the spirit emerges from it.” The lungs, as one of the five Zang organs, are located in the chest, with one on each side, lobed and loose in texture. They reside above the diaphragm, connecting to the trachea, opening to the nose, and directly communicating with the atmosphere. The physiological functions of the lungs include: the lungs govern Qi and control respiration, govern water, and connect to all vessels, regulating their functions. 1. The lungs govern Qi: ① The lungs govern the Qi of the entire body. This means the lungs have the role of managing and regulating the Qi of all Zang and Fu organs, participating in the generation of Qi through respiration and regulating the Qi mechanism. ② The lungs govern the Qi of respiration. The lungs are the site of gas exchange between the internal and external environments, meaning they inhale clean air from the environment and exhale turbid air from the body, achieving the function of gas exchange. 2. The lungs govern water: This refers to the lungs’ role in promoting and regulating the distribution, movement, and excretion of body fluids. As the highest organ, the lungs participate in regulating the metabolism of body fluids, hence they are called “the upper source of water” (from the “Xue Zheng Lun: Swelling”). 3. The lungs connect to all vessels: All blood vessels converge and flow through the lungs, where gas exchange occurs during respiration, thus the lungs connect to all vessels. 4. The lungs govern regulation: Regulation refers to governance and adjustment. The lungs assist the heart in regulating and adjusting the Qi, blood, fluids, and physiological functions of the Zang and Fu organs. The heart is the monarch, while the lungs are the minister. The reason why the various Zang and Fu organs operate according to certain rules relies on the lungs assisting the heart in governance and regulation. Therefore, the lungs are called “the ministerial official.” The regulatory functions of the lungs are primarily reflected in four aspects: (1) The lungs govern respiration: The rhythmic inhalation and exhalation of the lungs, breathing in turbid air and exhaling clean air, play a crucial role in ensuring smooth respiration. (2) Regulating the Qi mechanism: The lungs govern Qi, regulating the rise and fall of Qi, ensuring smooth Qi movement throughout the body. The saying goes, “The lungs govern Qi; when Qi is regulated, the Zang and Fu organs are treated” (from the “Lei Jing: Zang Xiang Lei”). (3) Assisting the heart in blood circulation: The lungs connect to all vessels, assisting the heart in circulating blood, promoting and regulating the flow of blood throughout the body. “All Qi belongs to the lungs”; when Qi moves, blood also moves. (4) Promoting and regulating: The lungs’ promotion and regulation govern the distribution, movement, and excretion of body fluids. Therefore, the lungs govern regulation, which is a high-level summary of the lungs’ primary physiological functions. The physiological characteristics of the lungs: 1. The lungs are the protective cover: The cover refers to an umbrella. The protective cover originally referred to the cover of ancient emperors’ carriages. The lungs are the protective cover, meaning they are the highest organ in the body cavity, protecting the other organs and resisting external pathogens. The lungs are located in the thoracic cavity, occupying the highest position among the five Zang organs, serving to cover the other organs, and they also govern the body’s exterior, thus they are called the protective cover. 2. The lungs are delicate organs: The lungs are delicate organs, meaning they are clear, empty, and tender, making them susceptible to external pathogens. Delicate means tender. The lungs are a clear and empty organ, and being in a high position, they are the protective cover for the other organs. The six external pathogens can invade the body, whether entering through the mouth and nose or invading the skin, making the lungs vulnerable to disease. The cold and heat changes in other organs often affect the lungs, as they are intolerant to cold and heat, making them delicate organs. The relationship between the lungs and form, orifices, will, fluids, and time: the lungs are connected to the skin, and their manifestation is in the hair. The lungs are associated with the nose, and the throat is the portal of the lungs. The lungs correspond to sadness in emotions. The lungs are related to nasal discharge in fluids. The lungs correspond to autumn heat. The lungs externally correspond to the abdomen. “The lungs are the ministerial official, and regulation emerges from them.” The spleen, as one of the five Zang organs, is located in the upper abdominal cavity, beneath the diaphragm, connected to the stomach by a membrane, resembling a dog’s tongue and shaped like a chicken comb, forming the spleen system with the stomach, flesh, lips, and mouth. The physiological functions of the spleen include: the spleen governs transportation and transformation, and the spleen governs blood regulation. 1. The spleen governs transportation and transformation: Transportation refers to the movement and delivery, while transformation refers to digestion and absorption. The spleen governs transportation and transformation, meaning it has the function of converting food and drink into essence and transporting the essence to all Zang and Fu organs. In essence, the spleen is responsible for the digestion, absorption, and transportation of nutrients. This includes both the transportation of food and the transportation of body fluids. (1) Transportation of food: Food refers to all kinds of food and drink. The spleen’s transportation of food refers to its role in digesting and absorbing food. The process of the spleen’s transportation of food involves: first, the food that has been initially digested by the stomach is further processed by the spleen to transform it into essence (also known as food essence); second, the spleen absorbs the essence and transports it to the entire body; third, the essence is sent to the heart and lungs to be transformed into Qi and blood, which are vital life substances. In summary, the spleen governs the transportation of food, including the digestion of food, absorption of essence, and transformation of essence into Qi and blood. (2) Transportation of body fluids: The transportation of body fluids refers to the spleen’s role in absorbing and transporting body fluids, regulating the body’s fluid metabolism. The spleen works with the lungs, kidneys, San Jiao, and bladder to regulate and maintain the balance of body fluid metabolism. The spleen’s function of governing the transportation of body fluids is a key link in regulating the body’s fluid metabolism. During the process of fluid metabolism, the spleen transports the absorbed essence while also delivering the necessary body fluids (Jin Ye) through the heart and lungs to nourish and moisten the body. It also promptly transports the used body fluids back to the kidneys, where they are transformed into urine and expelled, thus maintaining the balance of body fluid metabolism. The spleen is located in the middle Jiao, serving as the hub for the rise and fall of Qi and the metabolism of body fluids, thus playing a crucial role in the body’s fluid metabolism. Therefore, when the spleen’s function of governing the transportation of body fluids is strong, it ensures that all tissues receive adequate moisture without excessive retention. Conversely, if the spleen’s function is impaired, it will lead to stagnation of body fluids, resulting in pathological products such as dampness and phlegm, and even edema. 2. The spleen governs blood regulation: The spleen’s role in blood regulation refers to its ability to control and manage blood, ensuring it flows within the vessels without overflowing. The spleen’s Qi can regulate blood throughout the body, allowing it to circulate normally without spilling outside the vessels. The spleen’s blood regulation is achieved through the action of Qi on blood. The spleen is the source of Qi and blood transformation; Qi leads blood, and blood follows Qi. When the spleen’s transportation function is strong, Qi and blood are abundant, allowing Qi to regulate blood; when Qi is strong, the regulating function is also strong, preventing blood from leaking outside the vessels and causing bleeding. Conversely, if the spleen’s transportation function declines, it will lead to insufficient transformation, resulting in Qi and blood deficiency, causing blood to leave the vessels and leading to bleeding. Thus, the spleen’s blood regulation is a concrete manifestation of Qi’s action on blood, as stated, “The spleen regulates blood, meaning blood flows according to the spleen’s Qi” (from the “Yi Yan: Blood”). The physiological characteristics of the spleen: 1. The spleen’s Qi rises. The spleen’s nature is to rise, meaning the movement of the spleen’s Qi is primarily upward; when the spleen rises, its Qi is strong. The spleen’s Qi maintains the relative position of the organs. 2. The spleen prefers dryness and dislikes dampness. The spleen governs dampness and dislikes dampness because dampness harms the spleen, leading to impaired function and resulting in dampness in patients, referred to as “dampness obstructing the spleen’s earth.” The relationship between the spleen and form, orifices, will, fluids, and time: the spleen is connected to the flesh, governing the limbs. Its manifestation is in the lips. The spleen is associated with the mouth. The spleen corresponds to thought in emotions. The spleen is related to saliva in fluids. The spleen corresponds to the late summer season. The spleen externally corresponds to the lower abdomen. “The spleen is the official of advice, knowing the surroundings.” The liver, as one of the five Zang organs, is located in the abdomen, beneath the diaphragm, on the right side, and is part of the liver system, which includes the gallbladder, eyes, tendons, and nails. The liver governs smooth flow, stores blood, and is responsible for emotional regulation, preferring Yang over Yin. In the Five Elements, it corresponds to wood and is associated with spring. The physiological functions of the liver include: the liver governs smooth flow and stores blood. 1. The liver governs smooth flow: This means the liver has the role of ensuring smoothness, comfort, and unobstructed flow to maintain the smooth movement of Qi throughout the body. The liver’s smooth flow function is crucial for the physiological activities of the body. (1) Regulating Qi movement: The liver’s smooth flow function is essential for the smooth movement of Qi throughout the body. Qi movement refers to the rise and fall of Qi, which is the basic form of Qi transformation. The human body is a system that continuously undergoes the rise and fall of Qi movement. The process of Qi movement is achieved through the functions of the Zang and Fu organs. The interconnection of the body’s Zang and Fu organs, Qi, blood, body fluids, and Yin-Yang relies on the smooth rise and fall of Qi. The liver’s smooth flow function plays a vital role in maintaining the balance and coordination of Qi movement among the various Zang and Fu organs. “All Qi transformations in the Zang and Fu organs must rely on the Qi transformation of the liver and gallbladder to be stimulated, in order to be smooth and not cause illness” (from the “Reading Medical Essays: Volume Four”). Therefore, when the liver’s smooth flow function is normal, Qi movement is smooth, Qi and blood are harmonized, meridians are unobstructed, and the activities of the Zang and Fu organs are coordinated. (2) Regulating emotions: Emotions refer to feelings and moods, which are a type of psychological process reflecting emotional changes. In TCM, emotions fall under the narrow sense of spirit, including joy, anger, worry, thought, sadness, fear, and surprise, collectively known as the seven emotions. The liver can regulate emotional activities through its smooth flow function, promoting emotional balance. (3) Promoting digestion and absorption: The spleen and stomach are the primary digestive organs. The stomach governs receiving, while the spleen governs transportation. The liver’s smooth flow is essential for maintaining normal digestion and absorption by the spleen and stomach. The liver promotes the spleen and stomach’s digestive and absorptive functions by coordinating the rise and fall of Qi in the spleen and stomach and secreting and excreting bile. (4) Maintaining blood circulation: The liver’s smooth flow directly affects Qi movement. Only when Qi movement is smooth can the heart govern blood vessels, the lungs assist the heart in circulating blood, and the spleen regulate blood, ensuring normal blood circulation. (5) Regulating fluid metabolism: The regulation of fluid metabolism is primarily accomplished by the lungs, spleen, kidneys, and other organs, but it is closely related to the liver. The liver governs smooth flow, which can regulate the Qi movement of the San Jiao, promoting the functions of the lungs, spleen, and kidneys in regulating fluid metabolism. The San Jiao serves as the pathway for fluid metabolism. “If the upper Jiao is not treated, water will invade the high source; if the middle Jiao is not treated, water will remain in the middle; if the lower Jiao is not treated, water will disrupt the two excretions. When the San Jiao regulates Qi, the vessels will be unobstructed, and the water pathways will be smooth” (from the “Lei Jing: Zang Xiang Lei”). The function of the San Jiao in regulating fluid metabolism is essentially a comprehensive function of the lungs, spleen, and kidneys in regulating fluid metabolism. The liver’s smooth flow function ensures that Qi movement is smooth, leading to the smooth flow of body fluids. This is the theoretical basis for regulating Qi to treat water-related issues. (6) Regulating sexual and reproductive functions: ① Regulating the Chong and Ren channels: Women’s physiological activities, such as menstruation, pregnancy, and childbirth, involve many organ functions, with the liver playing a crucial role. It is often said that “women rely on the liver for their innate constitution.” ② Regulating the essence chamber: The essence chamber is where men store their essence. Men’s reproductive capabilities are related to the abundance of kidney Qi, which promotes sexual maturity and maintains reproductive functions. The opening and closing of the essence chamber and the storage and release of semen are related to the functions of the liver and kidneys. “The one who governs closure and storage is the kidney, while the one who governs smooth flow is the liver” (from the “Ge Zhi Yu Lun: The Theory of Excess Yang and Insufficient Yin”). 2. The liver governs blood storage: The liver’s blood storage refers to its ability to store blood, prevent bleeding, and regulate blood volume. Therefore, it is known as the “sea of blood.” ① Storing blood: Blood originates from the essence of food and drink, transformed by the spleen and stored in the liver. The liver stores a certain amount of blood, which nourishes itself, regulates the liver’s Yang Qi, and maintains the balance of Yin and Yang, as well as the harmony of Qi and blood. If the liver does not store blood, it can lead to insufficient liver blood and excessive Yang Qi, resulting in bleeding. ② Regulating blood volume: Under normal physiological conditions, the blood volume in different parts of the body is relatively constant. However, the blood volume in different parts can change according to different physiological conditions. When the body is active or emotionally excited, the demand for blood in various parts increases, prompting the liver to distribute stored blood to meet the body’s needs. Conversely, when people are at rest and emotionally stable, the demand for blood decreases, and some blood returns to the liver. “When a person is active, blood flows through the meridians; when a person is at rest, blood returns to the liver.” The liver’s ability to store blood and regulate blood volume is why it is called the “sea of blood.” The physiological characteristics of the liver: 1. The liver prefers smooth flow: Smooth flow means comfort, relaxation, and unobstructed movement. Suppression means obstruction and stagnation. The liver, as the organ of wind and wood, prefers smooth flow and dislikes suppression. The liver’s Qi should remain gentle and smooth to maintain its normal physiological functions. 2. The liver is a strong organ. The relationship between the liver and form, orifices, will, fluids, and time: The liver is connected to the tendons, and its manifestation is in the nails. The liver is associated with the eyes. The liver corresponds to anger in emotions. The liver is related to tears in fluids. The liver corresponds to spring heat. The liver externally corresponds to the sides of the body. “The liver is the official of the general, and strategies emerge from it.” The kidneys, as one of the five Zang organs, have the following physiological functions: the kidneys store essence, govern the intake of Qi, and regulate water. 1. The kidneys store essence: The kidneys’ storage of essence refers to their role in storing and safeguarding the essence of the body. The physiological functions of essence include: the essence in the kidneys promotes growth, development, and reproduction, and it also participates in blood production, enhancing the body’s resistance to disease. ① Promoting reproduction: Kidney essence is the original substance for embryonic development and promotes the maturation of reproductive functions. The generation, storage, and release of kidney essence are crucial for reproduction. The development of male and female reproductive organs and their reproductive capabilities depend on the abundance of kidney essence, which is why it is said that “the kidneys govern reproduction.” Based on this theory, tonifying the kidneys and preserving essence becomes one of the important methods for treating reproductive and sexual function abnormalities. ② Promoting growth and development: Life follows a natural cycle of birth, growth, maturity, aging, and death. The time a person survives from birth through development, growth, maturity, aging, and ultimately death is referred to as lifespan, typically measured by age. ③ Participating in blood production: The kidneys store essence, which can transform into marrow, and marrow can be converted into blood. “Blood is a product of essence, but essence is stored in the kidneys, which is limited, while blood is abundant in the Chong, reaching everywhere” (from the “Jing Yue Quan Shu: Blood Evidence”). Therefore, it is said that the source of blood lies in the kidneys. Thus, in clinical practice, methods that tonify essence and marrow are often used to treat blood deficiency. ④ Resisting external pathogens: Kidney essence has the ability to resist external pathogens, preventing disease. “Those with abundant essence do not fall ill, while those with insufficient essence are prone to all diseases” (from the “Feng’s Secret Record”). When essence is abundant, vitality is strong, and the body’s defenses are robust, making it difficult for pathogens to invade. Conversely, when essence is deficient, vitality weakens, defenses are compromised, and pathogens can invade, leading to illness. Therefore, it is said that “those who store essence do not fall ill in spring” (from the “Suwen: Jin Gui Zhen Yan Lun”). If essence is not stored in winter, one will surely fall ill in spring. The ability of kidney essence to resist external pathogens falls under the category of Zheng Qi, which aligns with the meaning of “when Zheng Qi is present, pathogens cannot invade” and “wherever pathogens gather, Qi must be deficient.” 2. The kidneys govern water: Water refers to the totality of normal fluids in the body. The kidneys govern water, meaning they have the role of storing essence and regulating water. 3. The kidneys govern the intake of Qi: The intake refers to the ability to capture and receive. The kidneys govern the intake of Qi, meaning they have the role of capturing the Qi inhaled by the lungs and regulating respiration. Although the lungs govern respiration, the inhaled Qi must descend to the kidneys, where the kidney Qi captures it, allowing for smooth and regulated breathing. “Qi originates in the kidneys and also returns to the kidneys, hence it is said that the kidneys govern the intake of Qi, and their breath is deep” (from the “Yi Yan: Qi”). “The lungs govern Qi, while the kidneys govern the root of Qi; the lungs govern exhalation, while the kidneys govern inhalation; Yin and Yang intersect, and breathing is harmonious” (from the “Lei Zheng Zhi Cai: Volume Two”). The physiological characteristics of the kidneys: the kidneys govern closure and storage: closure, also known as sealing and storage, refers to the ability to securely store and safeguard. The kidneys’ role in closure and storage refers to their ability to store the essence of the Zang and Fu organs. Closure is an important physiological characteristic of the kidneys. The kidneys are the source of innate essence, the root of life, storing true Yin and housing original Yang, making them the water and fire organs. The kidneys store essence, which should be preserved and not leaked; the kidneys govern Ming fire, which should remain hidden and not exposed. A person’s life originates from the kidneys, growth and development depend on the kidneys, and life activities rely on the kidneys. The kidneys are where the body’s Yin essence gathers; when kidney essence is abundant, the source of transformation is sufficient. The relationship between the kidneys and form, orifices, will, fluids, and time: the kidneys are connected to the bones, producing marrow, and their manifestation is in the hair. The kidneys are associated with the ears and the two Yin orifices. The kidneys correspond to fear in emotions. The kidneys are related to saliva in fluids. The kidneys correspond to winter heat. The kidneys externally correspond to the waist. “The kidneys are the official of strength, and skills emerge from them.” The six Fu organs refer to the gallbladder, stomach, large intestine, small intestine, San Jiao, and bladder. The Fu organs, known as the “府” (Fu), have the meaning of storage. The primary physiological function of the six Fu organs is to receive, digest, separate the clear from the turbid, transform the essence, and expel waste from the body without allowing it to remain. Therefore, the six Fu organs should maintain harmony and smoothness. The specific physiological functions of the six Fu organs include: food enters the stomach, where it is digested, then moves to the small intestine for further digestion, separating the clear from the turbid, and absorbing the essence. The large intestine receives the food residue from the small intestine, absorbing excess water to form feces, which are expelled from the body. During the digestion and absorption of food, the gallbladder secretes bile into the small intestine to assist in digestion. The San Jiao not only serves as a conduit for transformation but also plays a crucial role in managing Qi, facilitating the normal functioning of the transformation process. The gallbladder is attached to the short lobe of the liver, connected to the liver, and is a hollow sac-like organ. The gallbladder is one of the six Fu organs and also one of the extraordinary reservoirs. Its primary functions include: 1. Storing and excreting bile, which is bitter and yellow-green, promoting the digestion and absorption of food. Bile is transformed from the essence of the liver and stored in the gallbladder, hence it is called the “reservoir of essence” and “the clean reservoir.” The secretion of bile relies on the regulation and control of the liver’s smooth flow function. When the liver’s smooth flow function is normal, bile secretion is unobstructed, and the spleen and stomach’s transformation functions are robust. If liver Qi is stagnant, bile secretion may be hindered, affecting the spleen and stomach’s digestive functions, leading to symptoms such as chest and rib fullness, loss of appetite, or irregular bowel movements. If liver smooth flow is excessive, bile Qi may reverse, causing bitterness in the mouth and vomiting of yellow-green bile. If damp-heat accumulates in the liver and gallbladder, bile may overflow into the skin, resulting in jaundice. If bile secretion is obstructed for a long time, it can lead to the accumulation of stones. 2. Governing decision-making: Decision-making falls under the realm of cognition. The gallbladder has the ability to judge matters and make decisions. This function is crucial for defending against and eliminating the adverse effects of certain mental stimuli, maintaining and controlling the normal flow of Qi and blood, and ensuring the coordination of the Zang and Fu organs. Clinically, individuals with insufficient gallbladder Qi often exhibit fearfulness and indecisiveness. The stomach is located beneath the diaphragm, connecting to the esophagus above and the small intestine below. The upper opening of the stomach is called the cardia, while the lower opening is the pylorus. The stomach is divided into three parts: upper, middle, and lower, hence it is also referred to as the stomach cavity. The primary functions of the stomach include: 1. Governing the reception and digestion of food. Reception refers to the acceptance and accommodation of food, while digestion refers to the initial breakdown of food into chyme. The stomach’s role in receiving and digesting food is to accommodate food transmitted from the esophagus and perform initial digestion before passing it to the small intestine, hence the stomach is known as the “sea of food and drink” and “the granary.” The stomach’s reception and digestion provide the material basis for the spleen’s transportation function. Therefore, the spleen and stomach are often referred to as the “foundation of postnatal life, the source of Qi and blood transformation,” and the functions of the spleen and stomach are summarized as “stomach Qi.” The source of postnatal nutrition is closely related to the strength of “stomach Qi,” and clinically, the strength of “stomach Qi” is often used as an important basis for assessing the severity of diseases and prognosis, with treatment focusing on “preserving stomach Qi.” If the stomach’s reception and digestion functions are impaired, symptoms such as stomach distension and pain, loss of appetite, acid regurgitation, and hunger may occur. If stomach Qi is severely damaged, it becomes difficult to ingest food, leading to a poor prognosis, and in severe cases, the loss of stomach Qi can be life-threatening, hence the saying, “A person lives with stomach Qi; without it, they die.” 2. Governing downward movement: Downward movement refers to the smooth descent of stomach Qi. Food enters the stomach, where it is digested and then passed to the small intestine for further digestion and absorption. The clear substances are transported by the spleen, while the turbid substances are passed to the large intestine, where they are transformed into waste and expelled. The entire process relies on the stomach Qi’s downward movement. Therefore, the stomach’s governing of downward movement means it can pass the chyme to the small and large intestines and expel waste. The stomach’s governing of downward movement is a prerequisite for reception. If the stomach fails to move downward, it not only decreases appetite but also causes upward turbid Qi, leading to symptoms such as bad breath, abdominal distension and pain, acid regurgitation, hiccups, constipation, and even nausea and vomiting. The small intestine is located in the abdomen, connecting to the stomach above through the pylorus and to the large intestine below through the ileocecal valve. It is a hollow tubular organ, coiled and folded. Its primary functions include: 1. Governing reception and transformation. Reception refers to the acceptance and accommodation of food, while transformation refers to the further digestion and absorption of the food. The small intestine receives food that has been initially digested by the stomach, serving as a container, and it must retain the food for a period to allow for further digestion and absorption. Transformation refers to the digestion and conversion of the food into essence. If the small intestine’s functions of reception and transformation are impaired, symptoms such as abdominal distension and pain, diarrhea, or loose stools may occur. 2. Separating the clear from the turbid: The small intestine separates the clear essence from the turbid waste. The large intestine is located in the abdominal cavity, connecting to the small intestine above through the ileocecal valve and to the anus below. The large intestine’s primary function is to transmit and transform waste. Transmission and transformation refer to the processes of conducting and changing. The large intestine receives the food residue from the small intestine and absorbs excess water to form feces, which are expelled from the body, hence the large intestine is known as the “transmission official.” The large intestine’s transmission and transformation functions extend the stomach’s downward movement and are closely related to the spleen’s upward movement, the lungs’ downward movement, and the kidneys’ vaporization functions. If the large intestine’s transmission is impaired, it can lead to abnormal bowel movements, such as damp-heat in the large intestine, Qi stagnation, resulting in abdominal pain and diarrhea, urgency, and blood in the stool. If the large intestine is filled with heat, the intestinal fluids may dry up, leading to constipation. If the large intestine is deficient and cold, it may lead to mixed food and liquid, causing bowel sounds and diarrhea. The bladder is located in the lower abdomen and is a hollow sac-like organ. It connects to the kidneys above through the ureters and opens to the front through the urethra. The primary functions of the bladder include storing and excreting urine. Urine is transformed from body fluids, and its formation relies on the kidneys’ vaporization function, which descends to the bladder and regulates its opening and closing, ultimately expelling urine. Therefore, the bladder’s vaporization function is based on the kidneys’ vaporization function. If the functions of the kidneys and bladder are impaired, it can lead to urinary difficulties, such as urinary retention, frequent urination, urgency, painful urination, or incontinence. The San Jiao refers to the upper, middle, and lower Jiao, collectively known as the San Jiao, and is one of the six Fu organs. Among the Zang and Fu organs, the San Jiao is the largest, yet it is considered to have no physical form, hence it is called the “lonely Fu.” From a positional perspective, the upper Jiao is above the diaphragm, including the heart and lungs; the middle Jiao is below the diaphragm and above the navel, including the liver, gallbladder, spleen, and stomach; the lower Jiao is below the navel, including the large and small intestines, bladder, and kidneys. The San Jiao is interrelated with the pericardium. The specific functions of the San Jiao include: 1. Governing Qi, overseeing the body’s Qi transformation activities. The San Jiao serves as the pathway for the body’s Yuan Qi. Yuan Qi originates in the kidneys and must pass through the San Jiao to be distributed throughout the body, stimulating and promoting the functional activities of the Zang and Fu organs, thus maintaining normal life activities. Yuan Qi is the driving force behind Qi transformation activities, and the San Jiao’s passage of Yuan Qi is crucial for the normal functioning of Qi transformation. Therefore, the San Jiao “governs Qi and oversees the body’s Qi transformation activities.” 2. Serving as the pathway for the movement of body fluids. This means the San Jiao has the role of facilitating the movement of fluids. Although the metabolism of body fluids relies on the cooperation of various organs, it must also depend on the smooth pathways of the San Jiao to function normally. If the San Jiao’s pathways are obstructed, the functions of the lungs, spleen, and kidneys in regulating fluid metabolism will be difficult to perform. Therefore, the San Jiao plays an important role in fluid metabolism. The gallbladder is the official of decision-making, the stomach is the official of storage, the small intestine is the official of reception, the large intestine is the official of transmission, the San Jiao is the official of regulation, and the bladder is the official of storage. The theory of the Five Elements and the relationships between the Zang organs: The relationships between the five Zang organs are explained through the theory of the Five Elements. For example, wood generates fire, meaning the liver (Mu) nourishes the heart (Huo). The liver stores blood, while the heart governs blood vessels. When the liver’s blood storage function is normal, it supports the heart’s blood vessel function. Fire generates earth, meaning the heart’s heat warms the spleen (Tu). The heart governs blood vessels and spirit, while the spleen governs transportation and blood production. When the heart’s blood vessel function is normal, it nourishes the spleen, allowing it to perform its functions of transportation, blood production, and regulation. Earth generates metal, meaning the spleen (Tu) supports the lungs (Jin). The spleen can nourish Qi, transform essence into Qi and blood, and supply the lungs, promoting their function of governing Qi. Metal generates water, meaning the lungs (Jin) nourish the kidneys (Shui). The lungs govern clarity, while the kidneys govern essence storage. The lungs’ Qi promotes the kidneys’ ability to store essence and regulate water. Water generates wood, meaning the kidneys (Shui) nourish the liver (Mu). The kidneys store essence, while the liver stores blood. Kidney essence can transform into liver blood, supporting the liver’s normal function. This interdependent relationship among the five organs is explained through the theory of the Five Elements. The relationships between the Zang organs: 1. Heart and lungs: The heart governs blood, while the lungs govern Qi. The maintenance of the functional activities of the body’s organs relies on the circulation of Qi and blood to deliver nutrients. Although the normal flow of blood is governed by the heart, it must rely on the lungs’ Qi to propel it. The Qi stored in the lungs must be infused into the heart’s vessels to reach the entire body. 2. Heart and liver: The heart is the driving force of blood circulation, while the liver is an important organ for storing blood. Therefore, when the heart’s blood is abundant, the liver’s blood storage is also sufficient, nourishing the tendons and promoting the normal activities of the body’s limbs and tissues. If the heart’s blood is deficient, it can lead to insufficient liver blood, resulting in symptoms such as muscle pain, cramps, and spasms. Conversely, if liver Qi stagnates and transforms into fire, it can disturb the heart, leading to symptoms such as irritability and insomnia. 3. Heart and spleen: The essence transformed by the spleen must rely on the flow of blood to be distributed throughout the body. The heart’s blood must also depend on the essence absorbed and transported by the spleen. Additionally, the heart governs blood, while the spleen regulates blood; the spleen’s normal function is essential for regulating blood. If the spleen’s Qi is weak, it can lead to blood not circulating properly. 4. Heart and kidneys: The heart and kidneys interact and constrain each other to maintain a relative balance in physiological functions. Under normal conditions, the heart’s Yang continuously descends, while the kidneys’ Yin continuously ascends, creating a balance known as “heart-kidney interaction.” In pathological conditions, if kidney Yin is insufficient and cannot ascend to support the heart, it can lead to excessive heart Yang, resulting in an imbalance known as “heart-kidney non-interaction.” 5. Liver and spleen: The liver stores blood, while the spleen governs the transportation of essence and blood production. If the spleen is deficient and affects blood production, it can lead to liver blood deficiency, resulting in symptoms such as dizziness, blurred vision, and visual disturbances. The liver prefers smooth flow and dislikes stagnation; if liver Qi stagnates and obstructs the spleen, it can lead to abdominal pain and diarrhea. 6. Liver and lungs: The liver’s meridians connect to the lungs, establishing a relationship between the two. The liver’s Qi ascends, while the lungs’ Qi descends, affecting the rise and fall of Qi in the body. If liver Qi rises excessively, it can hinder the lungs’ ability to descend, leading to symptoms such as chest tightness and shortness of breath. If liver fire invades the lungs, it can cause symptoms such as chest and rib pain, coughing, or blood-streaked phlegm. 7. Liver and kidneys: The kidneys store essence, while the liver stores blood. The liver’s blood requires nourishment from kidney essence, and kidney essence also needs continuous supplementation from the liver, creating a mutually dependent relationship. If kidney essence is insufficient, it can lead to liver blood deficiency. Conversely, if liver blood is deficient, it can affect the generation of kidney essence. If kidney Yin is insufficient, it can lead to liver Yin deficiency, resulting in symptoms such as dizziness, tinnitus, tremors, numbness, and spasms. 8. Lungs and spleen: The spleen transports the essence of food and drink to the lungs, combining with the essence inhaled by the lungs to form the Zong Qi (also known as lung Qi). The strength of lung Qi is related to the spleen’s ability to transform essence; thus, when spleen Qi is strong, lung Qi is abundant. If the spleen is deficient and affects the lungs, symptoms such as reduced appetite, lethargy, loose stools, and cough may occur. Clinically, the method of “tonifying the spleen and benefiting the lungs” is often used for treatment. For example, in cases of chronic cough with abundant thin white phlegm, easy to expectorate, fatigue, and reduced appetite, although the disease appears in the lungs, the root cause lies in the spleen, necessitating the use of methods to “strengthen the spleen, dry dampness, and transform phlegm” for effective results. The saying goes, “The lungs are the storage vessel for phlegm, while the spleen is the source of phlegm.” This illustrates the relationship between the spleen and lungs. 9. Spleen and kidneys: The spleen’s Yang relies on the kidneys’ Yang for warmth to function properly. If kidney Yang is insufficient, it can weaken spleen Yang, leading to impaired transportation and resulting in symptoms such as diarrhea, undigested food, and edema. Conversely, if spleen Yang is weak, it can lead to kidney Yang deficiency, resulting in symptoms such as cold pain in the lower abdomen, difficulty in bowel movements, and cold limbs. 10. Lungs and kidneys: The lungs govern the descent of Qi, regulating the movement of water, while the kidneys govern water. The kidneys’ Yang vaporizes water, allowing it to descend to the bladder, which also relies on the kidneys’ Yang to function and expel urine. If the functions of the kidneys and bladder are impaired, it can lead to urinary difficulties, such as frequent urination or urinary retention. 11. Heart and kidneys: The heart and kidneys interact and constrain each other to maintain a relative balance in physiological functions, known as “heart-kidney interaction.” If kidney Yin is insufficient and heart fire is excessive, leading to a lack of coordination, it is referred to as “heart-kidney non-interaction,” resulting in symptoms such as forgetfulness, insomnia, palpitations, and nocturnal emissions. The heart and kidneys also have another physiological and pathological relationship: the interaction of heart Yang and kidney Yang, promoting each other. When heart Yang is sufficient, it indicates smooth blood circulation; if kidney Yang is weak (due to diminished Ming fire), it can lead to heart deficiency. Conversely, if heart Yang is deficient, it can also affect kidney Yang deficiency. 12. Heart and liver: The heart is the center of blood circulation, while the liver is an important organ for storing blood. Therefore, when heart blood is abundant, liver blood is also stored adequately, nourishing the tendons and promoting the normal activities of the body and limbs. If blood is insufficient, excessive consumption can lead to blood deficiency in the liver, resulting in symptoms such as muscle cramps, spasms, and tremors. This indicates that excessive consumption of heart blood leads to pathological changes due to insufficient nourishment from the liver. 13. Heart and spleen: The spleen’s transportation function requires the promotion of heart Yang, while the generation of heart blood must rely on the essence absorbed and transported by the spleen. On the other hand, the heart governs blood, while the spleen regulates blood; the spleen’s normal function is essential for regulating blood. If spleen Yang is weak, it can lead to blood not circulating properly. 14. Liver and spleen: The liver stores blood, while the spleen governs the transportation of essence and blood production. If the spleen is deficient and affects blood production, it can lead to liver blood deficiency, resulting in symptoms such as dizziness, blurred vision, and visual disturbances. 15. Spleen and lungs: The strength of lung Qi relies on the supply of food and drink essence, which is closely related to the spleen’s transformation. Therefore, if the spleen is deficient and affects the lungs, symptoms such as pale complexion, lethargy, reduced appetite, and cough may occur. Clinically, the method of “tonifying the spleen and benefiting the lungs” is often used for treatment. For example, in cases of chronic cough with abundant thin white phlegm, easy to expectorate, fatigue, and reduced appetite, although the disease appears in the lungs, the root cause lies in the spleen, necessitating the use of methods to “strengthen the spleen, dry dampness, and transform phlegm” for effective results. The saying goes, “The lungs are the storage vessel for phlegm, while the spleen is the source of phlegm.” This illustrates the relationship between the spleen and lungs. 16. Spleen and kidneys: The spleen’s Yang relies on the kidneys’ Yang for warmth to function properly. If kidney Yang is insufficient, it can weaken spleen Yang, leading to impaired transportation and resulting in symptoms such as diarrhea, undigested food, and edema. Conversely, if spleen Yang is weak, it can lead to kidney Yang deficiency, resulting in symptoms such as cold pain in the lower abdomen, difficulty in bowel movements, and cold limbs. 17. Lungs and liver: When liver fire is excessive, it can scorch the lungs, leading to symptoms such as dry cough or blood-streaked phlegm, chest and rib pain, and irritability. If liver Qi rises excessively, it can hinder the lungs’ ability to descend, leading to symptoms such as chest tightness and shortness of breath. 18. Kidneys and liver: The kidneys store essence, while the liver requires nourishment from kidney essence to maintain its normal function. If kidney Yin is insufficient, it can lead to liver Yin deficiency, resulting in symptoms such as dizziness, tinnitus, tremors, numbness, and spasms. Often, both the liver and kidneys are treated together using methods to nourish the kidneys and liver for effective results. 19. Kidneys and lungs: (1) From the perspective of fluid metabolism, the kidneys’ meridians connect to the lungs, managing the San Jiao. The upper part relies on the lungs for regulation, while the lower part relies on the kidneys for opening and closing, with the middle part relying on the spleen for transformation. Therefore, the lungs, spleen, and kidneys are closely related to the metabolism of body fluids. If one organ’s function is impaired, it can lead to fluid retention and edema. (2) From the perspective of Qi, the lungs govern respiration while the kidneys govern the intake of Qi. The two organs work together to maintain the rise and fall of Qi in the body. The relationship between the Fu organs: The six Fu organs are responsible for the transmission of food and drink, and they work together to complete the processes of reception, digestion, absorption, transmission, and excretion. The relationship between Zang and Fu organs: 1. Heart and small intestine: The meridians connect, and they are interrelated. If the heart has heat, it can lead to oral and tongue ulcers. If the heart’s heat transfers to the small intestine, it can lead to symptoms such as short and red urine, and painful urination. 2. Liver and gallbladder: The gallbladder is housed in the liver, and the Zang and Fu organs are interconnected. Bile originates from the liver; if the liver’s smooth flow is abnormal, it can affect the normal secretion of bile. Conversely, if bile secretion is abnormal, it can also affect the liver. Therefore, liver and gallbladder symptoms often occur simultaneously, such as jaundice, rib pain, bitterness in the mouth, and dizziness. 3. Spleen and stomach: In terms of characteristics, the spleen prefers dryness and dislikes dampness, while the stomach prefers moisture and dislikes dryness. The spleen governs rising, while the stomach governs descending. In terms of physiological functions, the stomach is the sea of food and drink, governing digestion, while the spleen governs the transportation of fluids. The two organs work together to complete the transformation of food and drink. If the spleen’s Qi does not rise, the stomach’s Qi will not descend, leading to symptoms such as poor appetite, nausea, abdominal distension, and constipation. If dietary habits are irregular, leading to the stomach’s inability to descend, it can affect the spleen’s ability to rise, resulting in symptoms such as abdominal distension and diarrhea. Due to the close relationship between the spleen and stomach in physiology, they often influence each other in pathology, so they are often discussed together in clinical practice, and treatment often involves both. 4. Lungs and large intestine: The meridians are connected, and they are interrelated. If lung Qi descends smoothly, the large intestine’s Qi can also flow smoothly, allowing it to perform its transmission function. Conversely, if the large intestine’s transmission is obstructed, it can hinder the lungs’ ability to descend, leading to symptoms such as shortness of breath and cough. For example, in treatment, if the lungs have excess heat, the large intestine can be purged to allow heat to be expelled. Conversely, if the large intestine is obstructed, it can also help the lungs’ Qi to flow smoothly, facilitating the large intestine’s Qi movement. 5. Kidneys and bladder: The meridians are connected, and they are interrelated. Physiologically, one is the water organ, and the other is the water Fu, working together to maintain the balance of fluid metabolism (with the kidneys being the primary organ). Kidney Yang vaporizes water, allowing it to descend to the bladder, which also relies on kidney Yang to function and expel urine. In pathology, if kidney Yang is insufficient, it can weaken bladder function, leading to symptoms such as frequent urination or urinary retention. If damp-heat accumulates in the bladder, it can also affect the kidneys, leading to symptoms such as low back pain and blood in the urine. 6. Pericardium and San Jiao: The meridians are connected, and they are interrelated. For example, in clinical practice, in cases of heat illness with damp-heat combined, if it lingers in the San Jiao, it can lead to symptoms such as chest tightness, heaviness, reduced urination, and loose stools, indicating that the disease is in the Qi level. If this development is not halted, the warm-heat pathogen can enter the nutrient level from the Qi level, penetrating the San Jiao into the pericardium, leading to symptoms such as confusion and delirium. Practical significance: The theory of the interrelationship between Zang and Fu organs has practical significance in acupuncture treatment. For example, in treating asthma, the hand Taiyin lung meridian is often paired with the hand Yangming meridian’s Hegu point, while the foot Yangming stomach meridian is often paired with the foot Taiyin spleen meridian’s Yinlingquan point, achieving satisfactory results. These applications are based on the theory of the interconnection of Zang and Fu organs through meridians. The spleen and stomach are the foundation of life. The human body is an integrated whole composed of Zang and Fu organs, meridians, skin, muscles, tendons, bones, essence, Qi, blood, and body fluids. The theory of Zang and Fu organs studies the physiological functions and pathological changes of the Zang and Fu organs and their interrelationships. The Zang organs include the heart, liver, spleen, lungs, and kidneys, collectively known as the five Zang organs. The pericardium, located around the heart, has connecting vessels and serves as a pathway for Qi and blood, also protecting the heart, thus it is also referred to as a Zang organ. The Fu organs include the gallbladder, stomach, small intestine, large intestine, bladder, and San Jiao, collectively known as the six Fu organs. The Zang organs are primarily responsible for storing essence, while the Fu organs are responsible for receiving, digesting, absorbing, transmitting, and excreting food. Therefore, the Zang organs focus on storage, while the Fu organs focus on transmission. The Zang and Fu organs are interconnected, whether between Zang and Zang, Fu and Fu, or Zang and Fu. The five Zang organs are also closely related to the five body types and the five senses and seven orifices. The relationship between the five Zang organs and the five body types is as follows: the heart governs the pulse, the liver governs the tendons, the spleen governs the muscles, the lungs govern the skin, and the kidneys govern the bones. The relationship between the five Zang organs and the five senses and seven orifices is as follows: the heart opens to the tongue, the liver opens to the eyes, the spleen opens to the mouth, the lungs open to the nose, and the kidneys open to the ears and the two Yin orifices (the nose, eyes, and ears each have two, along with the front and back Yin orifices, collectively known as the nine orifices). Because the five Zang organs are related to the five body types and the five senses and seven orifices, changes in the five Zang organs often reflect in the corresponding body tissues and orifices. TCM’s understanding of the functions and changes of the Zang and Fu organs has been somewhat coarse due to historical limitations. In TCM, the concept of Zang and Fu organs is not only anatomical but also physiological and pathological, so the concept of “Zang and Fu” in traditional Chinese medicine differs from the concept of “organs” in modern medicine. For example, in TCM, the “heart” does not completely equate to the modern medical heart; it encompasses not only the anatomical heart but also the physiological functions of certain organs in the circulatory and nervous systems. When studying traditional Chinese medicine, we should adopt a dialectical materialist perspective, integrating modern medicine to grasp its essence for analysis and research, eliminating the false and preserving the true, contributing to the creation of a unified new medicine in our country. Yin: The interconnections between the San Jiao’s Zang and Fu organs through meridians and the flow of Qi and blood form an organic whole. In a physiological state, they work both independently and cooperatively, constituting complex physiological activities. In a pathological state, they also influence each other. Therefore, their relationships can be reflected in physiological and pathological changes. Understanding these theories of Zang and Fu relationships has certain guiding significance for clinical diagnosis and treatment.