The Eight Extraordinary Meridians are interconnected with the twelve regular meridians and play a role in regulating the qi and blood of the twelve primary meridians. Therefore, the pathology of the Eight Extraordinary Meridians is also related to the entire body.1. Pathophysiology of the Du Mai (Governing Vessel)The Du Mai connects to the brain above and the kidneys below, overseeing the yang of the entire body. Thus, diseases of the yang meridians are often related to the Du Mai. Additionally, it shares an origin with the Chong Mai (Penetrating Vessel) in the uterus, so its pathology is often associated with gynecological disorders. Hence, it is said: “When the Du Mai is diseased, the spine is stiff and bends… and women are infertile” (from Suwen, Chapter on Bone Cavity). Other conditions such as cold in the back, stooped posture, lumbar pain, and epilepsy are also attributed to the Du Mai.2. Pathophysiology of the Chong and Ren Mai (Penetrating and Conception Vessels)The Ren Mai and Chong Mai both originate in the uterus, connect to the lips and mouth, and are associated with the liver and kidneys. The pathology of the Chong and Ren vessels primarily reflects on sexual and reproductive functions. For instance, congenital abnormalities of male genital function are attributed to the Chong and Ren. It is stated: “Those with congenital eunuchs… have insufficient Chong and Ren, with the reproductive vessels not formed, having qi but no blood, and the lips not nourished, hence infertility” (from Lingshu, Chapter on Five Sounds and Five Tastes). The pathology of the Chong and Ren is particularly important in gynecology, manifesting as irregular menstruation, excessive bleeding, leukorrhea, infertility, miscarriage, incomplete lochia, reduced lactation, congenital eunuchs, and hernias. Thus, it is said: “When the Ren Mai is diseased, men have internal accumulations of seven hernias, and women have leukorrhea and masses. When the Chong Mai is diseased, there is rebellious qi and abdominal urgency” (from Suwen, Chapter on Bone Cavity).3. Pathophysiology of the Dai Mai (Belt Vessel)The Dai Mai is related to gynecological issues such as threatened miscarriage, habitual miscarriage, and leukorrhea. The Dai Mai serves to restrain the fetus; if it is weak, it cannot hold the fetus securely, leading to miscarriage. Therefore, weakness of the Dai Mai results in easy miscarriage, and injury to the Dai Mai leads to instability of the fetus. Leukorrhea is a damp condition due to the Dai Mai’s inability to restrain, hence the name. Other conditions such as kidney deficiency and hernias are also related to the Dai Mai. As stated: “When the Dai Mai is diseased, there is abdominal fullness, and the waist feels as if sitting in water” (from Nanjing, Chapter 29).4. Pathophysiology of the Wei Mai (Linking Vessel)The Yang Wei is the linking vessel of the yang meridians, while the Yin Wei is the linking vessel of the yin meridians. Therefore, the Yang Wei manifests as diseases of the three yang meridians, and the Yin Wei manifests as diseases of the three yin meridians. As stated: “When the Yang Wei is diseased, there is suffering from cold and heat; when the Yin Wei is diseased, there is suffering from heart pain” (from Nanjing, Chapter 29). “Yang Wei cold and heat, dizziness and stiffness; Yin Wei heart pain, chest and flank stabbing” (from Siyan Jueyao).5. Pathophysiology of the Ji Mai (Trace Vessel)The Yin Jiao and Yang Ji meridians manifest as abnormalities in muscle movement and eyelid function. It is said: “Yin Jiao is diseased, with Yang slow and Yin rapid; Yang Ji is diseased, with Yin slow and Yang rapid” (from Nanjing, Chapter 29). “When qi is harmonized, it moistens the eyes; when qi is not nourished, the eyes do not close” (from Lingshu, Chapter on Pulse Measurement). This is because Yin Jiao is a differentiation of the foot Shaoyin, and Yang Jiao is a differentiation of the foot Taiyang. The qi of Ying and Wei passes through the Shaoyin and Taiyang meridians, converging in Yin Jiao and Yang Jiao, allowing the qi to nourish the eyes and muscles to control their movement.Pathophysiology of the Twelve Regular MeridiansEach meridian has a different path of circulation. When pathogenic factors invade the body, physiological functions change abnormally, and the meridians will reflect various symptoms and signs through the areas they traverse. For example, the Hand Yangming Large Intestine Meridian starts at the radial side of the fingertip, ascends along the radial side of the index finger, travels up the arm to the elbow, and enters the shoulder. Its branches extend from the supraclavicular fossa to the neck, passing through the cheek and entering the lower teeth, then exiting beside the mouth and intersecting at the philtrum. Therefore, when the Hand Yangming Large Intestine Meridian is affected, symptoms such as toothache, neck swelling, shoulder and upper arm pain, and limited movement of the index finger may occur, even presenting with redness, swelling, burning, or cold sensations. Thus, it is essential to familiarize oneself with the main diseases of each meridian during study.The twelve meridians have certain connections with the five zang and six fu organs. Therefore, when the twelve meridians are diseased, it will affect the corresponding organs, leading to pathological changes in the organs. For instance, the Foot Taiyin Spleen Meridian connects to the spleen and stomach, and has direct links with the heart, lungs, and intestines. Thus, when the Foot Taiyin Spleen Meridian is affected, it can cause dysfunction in the spleen and stomach, leading to symptoms such as stomach pain, nausea, reduced appetite, abdominal distension, diarrhea, or jaundice and swelling. The Foot Shaoyin Kidney Meridian connects to the kidneys and bladder, and has direct links with the liver, lungs, and heart. Therefore, when the Foot Shaoyin Meridian is affected, it can lead to edema, diarrhea, abdominal distension, impotence, dizziness, blurred vision, shortness of breath, and irritability. Therefore, analyzing the pathological changes of the meridians must be linked to the corresponding organs.1. Pathophysiology of Qi and Blood Deficiency and ExcessThe deficiency and excess of qi and blood in the meridians reflect the pathological changes of the meridians. When the qi and blood of the meridians are excessive, it can lead to hyperfunction of the corresponding organs and tissues, disrupting the physiological balance of the meridians and organs, resulting in disease. Conversely, when the qi and blood of the meridians are deficient, it can lead to reduced physiological function of the corresponding organs and tissues, resulting in disease. For example, in the case of the Foot Yangming Stomach Meridian, if the qi is excessive, it may present with fever, good appetite, yellow and red urine, and mania; if the qi is deficient, it may present with chills, abdominal distension, and weakness in the legs.2. Pathophysiology of Qi StagnationUnder normal circumstances, the qi of the meridians flows smoothly. When the qi of the meridians is obstructed, it affects the flow of qi and blood, often impacting the physiological functions of the corresponding organs and the areas traversed by the meridians. For example, exterior syndromes often present with generalized muscle soreness due to external pathogens binding the superficial meridians, leading to qi stagnation; stagnation of the qi in the Foot Jueyin Liver Meridian often leads to symptoms such as flank pain, goiter, plum pit qi, and breast lumps.The five sensory orifices are the external openings of the five zang organs, so when the qi is obstructed, it often affects the orifices, leading to corresponding symptoms. For instance, the liver opens to the eyes; if the liver is stagnant and transforms into fire, qi stagnation can lead to red, swollen eyes; if the kidney’s qi cannot ascend to nourish the ears, it can lead to deafness.Additionally, emotional changes often affect the flow of qi and blood in the meridians, leading to different pathological changes. For example, depression harms the liver, leading to liver qi stagnation, which can present as flank pain; excessive thinking harms the spleen, leading to impaired spleen qi, resulting in loss of appetite. Qi stagnation and poor circulation of blood in the meridians are often the main causes of qi stagnation and blood stasis in a specific meridian. In meridian diseases, the first manifestation is often qi stagnation, followed by poor blood circulation and other pathological changes.3. Pathophysiology of Qi ReversalThe reversal of qi and blood in the meridians is primarily due to the disruption of the normal ascending and descending functions of qi, leading to the upward or downward reversal of qi and blood, resulting in disease. Conversely, abnormal circulation of qi and blood will inevitably lead to qi reversal, and the two often influence each other.Reversal of qi and blood in the meridians often leads to disharmony between the yin and yang energies in the body, resulting in counterflow. For example, the Foot Taiyang Bladder Meridian starts at the inner canthus of the eye, ascends to the forehead, and connects to the brain. Therefore, if the qi of the Foot Taiyang Meridian is reversed, it can lead to symptoms such as heaviness and swelling in the head, and in severe cases, dizziness and fainting.Reversal of qi and blood can also lead to dysfunction of the physiological functions of the corresponding organs. For instance, reversal of qi in the Foot Taiyin Spleen Meridian can lead to dysfunction of the spleen and stomach, resulting in failure of clear qi to ascend, leading to diarrhea; if the turbid qi does not descend, it can lead to vomiting; if the clear and turbid are mixed, it can lead to cholera and diarrhea.Additionally, qi reversal is one of the causes of bleeding. For example, coughing up blood, vomiting blood, and nosebleeds caused by qi and fire rising are essentially related to qi reversal. For instance, coughing up blood due to liver fire invading the lungs is actually caused by the heat of the liver meridian leading to qi reversal and affecting the lungs.4. Pathophysiology of Qi ExhaustionThe exhaustion of qi and blood in the meridians refers to a pathological change where the qi is depleted to the point of exhaustion, leading to a life-threatening condition. Due to the different paths of the meridians and the varying functions of the corresponding organs, the symptoms that appear when the qi and blood of each meridian are exhausted are also distinct. For example, the Foot Taiyang Bladder Meridian starts at the eye and travels along the back, its qi nourishing the body’s surface. Therefore, if the qi of the Taiyang Meridian is exhausted, the eyes may lose their ability to move, the muscles may lose their nourishment, leading to spasms and convulsions, and the body’s defenses may fail, resulting in excessive sweating. Since the qi of the twelve meridians is interconnected, if one meridian’s qi is exhausted, the qi of the other twelve meridians will also be exhausted. Clinically, by observing the manifestations of qi and blood exhaustion in the meridians, one can assess the progression and prognosis of the disease.Pathophysiology of the Extraordinary Organs1. Pathophysiology of the BrainThe brain is an extremely important organ in the human body, responsible for mental, conscious, and cognitive activities, as well as the sensory functions of the eyes, ears, nose, and tongue, speech, and physical movement. Therefore, any changes in the brain can lead to various physiological dysfunctions or disorders. However, the brain is composed of marrow, so if the essence and qi of the kidneys are deficient, leading to insufficient marrow production, it can result in brain dysfunction, manifesting as reduced intelligence, delayed responses in vision, hearing, and speech, and impaired physical movement. The physiological activities of the brain rely on the nourishment of qi, blood, fluids, and the essence of food. Therefore, dysfunction of the heart, lungs, spleen, liver, and kidneys can lead to abnormal brain function, resulting in pathological manifestations of mental and emotional activities. Since the brain is located at the top of the body, it relies on the ascent of yang qi; therefore, if yang qi does not ascend, symptoms such as dizziness and deafness may occur.2. Pathophysiology of the Body and BonesThe marrow resides within the bones, including bone marrow, spinal cord, and brain marrow. The bones serve as the framework of the body, and the marrow nourishes the bones. Dysfunction of the marrow and bones primarily manifests as delayed growth and development, weak and brittle bones. Insufficient congenital endowment, inadequate nourishment from diet, or internal retention of heat can damage the yin fluids, or deficiency and cold in the lower jiao can lead to marrow depletion and bone weakness.3. Pathophysiology of the PulseThe pulse is the vessel of blood and is the channel for the circulation of qi and blood. The pulse should flow smoothly; if it is obstructed due to dryness of fluids, loss of nourishment, phlegm obstruction, qi stagnation, or cold coagulation, it can lead to stagnation of qi and blood. Conversely, qi stagnation or blood stasis can also affect the smooth flow of the pulse. If blood does not circulate through the meridians and spills outside the pulse, various bleeding disorders can occur.4. Pathophysiology of the Uterus in WomenThe uterus, also known as the womb, is primarily responsible for menstruation and fetal development. Dysfunction of the uterus primarily manifests as abnormalities in menstruation, pregnancy, and childbirth.There are many causes of uterine dysfunction, mainly including the following three aspects:1. Disharmony of qi and blood leading to uterine dysfunction: The menstrual cycle, pregnancy, childbirth, and lactation in women rely on blood, hence the saying, “Women are based on blood.” However, the function of blood relies entirely on qi. When qi and blood are harmonious, blood can fully exert its physiological effects; if qi and blood are disharmonious, it will inevitably affect the physiological function of the uterus, leading to various pathological changes.Heat in the blood, liver not storing blood or excessive dispersal, or the spleen not controlling blood or qi not restraining blood can all lead to excessive blood flow in the uterus, resulting in early menstruation, excessive menstrual flow, prolonged menstruation, or even metrorrhagia. If blood follows qi and fire rises, it can lead to menstrual vomiting, known as “reversed menstruation”; if due to qi stagnation, blood stasis, or insufficient qi and blood, or insufficient yang qi and cold in the lower jiao, it can lead to coldness in the uterus, resulting in late menstruation, reduced menstrual flow, dysmenorrhea, amenorrhea, or other pathological manifestations.If cold dampness or damp heat descends into the uterus, it can also lead to dysfunction of the uterine physiological function, which is essentially a disruption of the harmony of qi and blood.2. Dysfunction of the heart, liver, spleen, and kidneys leading to uterine dysfunction: Dysfunction of the heart, liver, spleen, and kidneys can not only lead to dysfunction of qi and blood but also to dysfunction of the uterus. This often occurs due to emotional disturbances, excessive fatigue, or irregular sexual activity, leading to uterine dysfunction. For example, excessive thinking harms the heart, depleting heart blood; excessive thinking harms the spleen, leading to insufficient qi and blood; excessive anger harms the liver, leading to liver dysfunction; excessive sexual activity harms the kidneys, leading to kidney essence deficiency, resulting in diminished “Tian Gui” (menstrual essence) and other pathological changes.3. Insufficient qi and blood in the Chong and Ren vessels leading to uterine dysfunction: The Chong Mai and Ren Mai both originate in the uterus, with the Chong serving as the sea of blood and the Ren governing the uterus. The fullness of qi and blood in the Chong and Ren vessels is the material basis for the physiological functions of the uterus. Since the Chong and Ren are associated with the liver and kidneys, dysfunction of the liver or kidneys can lead to insufficient qi and blood in the Chong and Ren vessels, resulting in uterine dysfunction. The Chong Mai is also associated with the Yangming meridian, which is abundant in qi and blood; therefore, if the spleen and stomach’s transport function is impaired, it can affect the fullness of qi and blood in the Chong and Ren vessels, leading to dysfunction of the uterine physiological function.In summary, the physiological function of the uterus is an integral part of the overall physiological function of the body, and dysfunction of the uterus is closely related to the state of the overall physiological function.In conclusion, the zang and fu organs are a unified entity of qi, blood, yin, and yang. The balance of qi, blood, yin, and yang plays a unique role in the physiological activities of the organs. Therefore, the fundamental principle of organ pathology is the imbalance of qi, blood, yin, and yang in the organs. Since the balance of qi, blood, yin, and yang is not uniform among the organs, some may have equal emphasis on qi and blood, while others may prioritize qi or yin, leading to distinct pathological characteristics of organ dysfunction.At the same time, the human body is a complete and unified entity, and the dysfunction of various physiological functions such as yin, yang, qi, blood, organs, and meridians can mutually influence each other, especially the complex pathological interactions between organs.Pathophysiology of the Six Fu Organs (San Jiao)Pathophysiology of the San Jiao1. Physiological and pathological characteristics of the San Jiao: The functions of the San Jiao encompass the qi transformation of the entire body, thus the pathological changes of the San Jiao reflect the pathological changes of the organs included in the upper, middle, and lower jiao.2. Basic pathological changes of the San Jiao: On one hand, it reflects the pathological changes of the heart, lungs, spleen, stomach, kidneys, and liver; on the other hand, it reflects the dysfunction of water and fluid metabolism.The dysfunction of the qi transformation in the San Jiao manifests in two aspects: one is the dysfunction of the qi of the heart and lungs, spleen and stomach, liver and gallbladder, kidneys and bladder, leading to abnormal physiological functions of the corresponding organs; for example, the heart’s blood circulation, the lungs’ respiration and dispersal, the spleen and stomach’s transport and transformation, the liver and gallbladder’s regulation, and the kidneys and bladder’s vaporization and drainage. All physiological functions rely on the coordinated balance of the movement of qi. Therefore, the abnormalities in the functions of the aforementioned organs can be attributed to the dysfunction of the qi transformation in the San Jiao. On the other hand, since the San Jiao is the channel for the movement of qi and fluids, it is the site of qi transformation activities. Therefore, the qi transformation function of the San Jiao encompasses the physiological functions of the lungs, spleen, and kidneys in regulating fluid metabolism. Thus, the dysfunction of the lung’s regulation can be attributed to the dysfunction of the qi transformation in the upper jiao; the dysfunction of the spleen and stomach’s transport of fluids, distribution of essence, and the elevation of clear and descent of turbid can be attributed to the dysfunction of the qi transformation in the middle jiao; the dysfunction of the kidneys and bladder’s vaporization and drainage, and the intestines’ transformation of waste can be attributed to the dysfunction of the qi transformation in the lower jiao. Therefore, the dysfunction of the qi transformation in the San Jiao encompasses the pathological mechanisms of fluid metabolism disorders throughout the body.Pathophysiology of the Six Fu Organs (Large Intestine)Pathophysiology of the Large Intestine1. Physiological and pathological characteristics of the large intestine: The large intestine is the organ of conduction, primarily responsible for fluid absorption. Its meridian connects to the lungs. Therefore, the pathology of the large intestine mainly manifests as abnormalities in its conduction and transformation functions, leading to abnormal bowel movements.2. Basic pathological changes of the large intestine: The large intestine has the functions of conducting waste and absorbing fluids; thus, when the large intestine is affected, its conduction and transformation functions are disrupted, leading to abnormal bowel movements such as diarrhea, dysentery, and constipation.Large Intestine Heat Accumulation: Large intestine heat accumulation often results from internal dryness and heat, or from heat from the lungs transferring to the large intestine, or from damp heat stagnation, leading to insufficient fluids in the large intestine and constipation, or heat accumulation causing overflow.Large Intestine Damp Heat: Damp heat accumulating in the large intestine or cold dampness transforming into heat can lead to diarrhea; if damp heat collides with qi and blood, it can result in dysentery with red and white stools and urgency; if damp heat obstructs the meridians, it can lead to hemorrhoids and fistulas.Large Intestine Deficiency Cold: Large intestine deficiency cold occurs when spleen yang is weak, leading to dysfunction in transformation, or when kidney yang is deficient, resulting in internal cold, leading to diarrhea, loose stools, and undigested food, or inability to control bowel movements, or yang deficiency leading to poor movement, or lung qi deficiency leading to weakness in large intestine conduction.Large Intestine Fluid Depletion: Large intestine fluid depletion occurs when the large intestine, which governs fluids, becomes dry, leading to obstruction in conduction and resulting in constipation.Pathophysiology of the Six Fu Organs (Bladder)Pathophysiology of the Bladder1. Physiological and pathological characteristics of the bladder: The bladder stores urine and is responsible for the transformation and movement of fluids. The bladder’s qi transformation function relies entirely on the kidneys, and its pathological changes mainly involve dysfunction of bladder qi transformation, leading to abnormal urination and changes in urine appearance.2. Basic pathological changes of the bladder: The main issues are dysfunction of bladder qi transformation, either due to qi obstruction or insufficient qi transformation.Qi obstruction: This can be due to excess pathogens or insufficient kidney yang, leading to poor qi transformation, resulting in reduced urination or urinary retention.Insufficient qi transformation: If the kidneys fail to contain and store, the qi loses its ability to hold, leading to insufficient qi transformation, resulting in enuresis or urinary incontinence.Damp Heat Descending: This can occur due to heart fire descending or damp heat descending into the bladder, leading to frequent urination, urgency, painful urination, and hematuria.Bladder Deficiency Cold: Bladder deficiency cold often results from kidney qi deficiency, leading to inability to contain, resulting in frequent urination, clear and long urination, or incontinence, with residual dripping or weak urination.Pathophysiology of the Six Fu Organs (Small Intestine)Pathophysiology of the Small Intestine1. Physiological and pathological characteristics of the small intestine: The small intestine receives the water and grains from the stomach, separating the clear from the turbid. The clear is distributed throughout the body, while the turbid is sent to the bladder and large intestine, and it is interconnected with the heart. Therefore, the pathological changes of the small intestine mainly reflect as abnormalities in bowel movements.2. Basic pathological changes of the small intestine: The main manifestations are failure to separate the clear from the turbid, leading to obstruction in transportation, primarily presenting as difficulty in urination and diarrhea.Failure to receive: Failure to receive leads to symptoms such as vomiting and abdominal pain.Failure to transform: Failure to transform leads to symptoms such as abdominal distension and undigested food.Failure to separate the clear from the turbid: This leads to vomiting and diarrhea, abdominal pain, and bowel sounds.Small Intestine Excess Heat: Small intestine excess heat often results from damp heat descending or heat from the heart transferring to the small intestine, presenting as frequent urination, or cloudy urine, or painful urination.Small Intestine Deficiency Cold: Small intestine deficiency cold often results from irregular eating habits damaging the spleen and stomach, presenting as bowel sounds, diarrhea, and abdominal pain that improves with pressure.Pathophysiology of the Six Fu Organs (Stomach)Pathophysiology of the Stomach1. Physiological and pathological characteristics of the stomach: The stomach is the sea of water and grains, preferring moisture and disliking dryness, and is responsible for receiving and digesting food. Therefore, dysfunction of the stomach primarily manifests as abnormalities in receiving and digesting food, as well as failure to harmonize and descend, leading to upward counterflow of stomach qi.2. Basic pathological changes of the stomach: The dysfunction of the stomach primarily manifests in terms of cold, heat, deficiency, and excess.(1) Stomach Qi Deficiency: Stomach qi deficiency often results from irregular eating habits, damaging stomach qi. Individuals with a weak constitution or prolonged illness may also lead to stomach qi deficiency. The pathological changes include: reduced receiving function, leading to fullness and discomfort in the stomach, poor appetite, and even loss of appetite; and upward counterflow of stomach qi, leading to belching, nausea, and vomiting.(2) Stomach Yin Deficiency: Stomach yin deficiency refers to the lack of yin fluids in the stomach, leading to insufficient nourishment and function. This often results from heat damaging the stomach fluids, or from prolonged illness leading to depletion of yin fluids. The pathological changes include: reduced receiving and digesting functions, such as loss of appetite or fullness after eating; upward counterflow of stomach qi, leading to discomfort and dry vomiting; and deficiency of yin fluids, leading to dry mouth and throat, reduced urination, constipation, and a red tongue with little coating.(3) Stomach Cold: Stomach cold often results from excessive consumption of cold foods or the use of cold medicines, damaging stomach yang. The pathological changes include: reduced digestive ability, often presenting as vomiting clear fluids and inability to digest food; and cold stagnation, leading to abdominal pain that may be persistent or severe.(4) Stomach Heat (Fire): Stomach heat often results from excessive stomach yang combined with emotional heat, or from heat entering the interior, or from excessive consumption of spicy and hot foods, leading to excessive heat in the stomach. The main pathological changes include: excessive digestive function, leading to good appetite; and upward counterflow of stomach qi, leading to bitter taste, nausea, and vomiting; and upward fire leading to swollen gums, or bleeding.Pathophysiology of the Six Fu Organs (Gallbladder)Pathophysiology of the Gallbladder1. Physiological and pathological characteristics of the gallbladder: The gallbladder is attached to the liver and is associated with the liver, serving as a clear organ, embodying the energy of spring wood, characterized by its firmness and decisiveness. Therefore, gallbladder pathology often manifests as symptoms of excessive yang fire, often with phlegm. Since heat can scorch fluids and lead to phlegm, gallbladder diseases often accompany phlegm, with phlegm and fire obstructing the heart spirit.2. Basic pathological changes of the gallbladder: These primarily reflect abnormalities in bile storage and secretion, as well as disturbances in mental state.(1) Bile secretion and excretion disorders: Emotional disturbances can lead to liver dysfunction, or damp heat in the middle jiao can obstruct the liver and gallbladder qi, leading to abnormal bile secretion and excretion. Bile excretion disorders can exacerbate liver qi stagnation, obstructing the normal function of the spleen and stomach, and can even lead to jaundice.(2) Gallbladder heat and phlegm obstructing the heart spirit: Gallbladder heat and phlegm can disturb the heart spirit, leading to symptoms such as irritability, insomnia, and nightmares.Pathophysiology of the Five Zang Organs (Kidneys)Pathophysiology of the Kidneys1. Physiological and pathological characteristics of the kidneys: The kidneys are the organs of water and fire, storing true yin and housing true yang, serving as the foundation of congenital essence and the root of life, responsible for storing essence, receiving qi, and governing water, opening to the ears and the two yin, with their manifestation in hair. The kidneys are closely related to the bladder. Therefore, sufficient kidney essence leads to strong bones, firm teeth, full marrow, sharp intellect, clear hearing, and bright vision; sufficient ming fire leads to robust yang qi in the five zang and six fu organs. Therefore, any abnormalities related to growth, reproductive functions, and fluid metabolism, as well as certain diseases of the brain, marrow, bones, and some respiratory and urinary functions, are often related to kidney dysfunction.The kidneys are the repository of the body’s yin and yang. The essence and qi of the kidneys are fundamental to human reproductive development and should be preserved rather than leaked. Preservation maintains normal physiological functions, while depletion leads to weakness and various diseases. Therefore, kidney pathology is often characterized by deficiency rather than excess.The kidneys contain both water and fire, yin and yang. When yin and yang are balanced, the functions are normal. Pathological changes primarily manifest as imbalances of water, fire, yin, and yang, with distinctions between deficiency and excess. Diseases caused by excess are classified as excess, such as external cold and dampness, or damp heat obstructing the kidneys, which are often excess conditions that can turn into deficiency over time. Diseases caused by deficiency are classified as deficiency. Kidney deficiency can be divided into yin and yang deficiency, and deficiency of essence and qi. However, prolonged deficiency can lead to both yin and yang deficiency, or vice versa, resulting in both yin and yang being deficient.2. Basic pathological changes of the kidneys: Kidney diseases are often characterized by deficiency, generally divided into yin deficiency and yang deficiency.(1) Kidney Yang and Qi Dysfunction: Kidney yang and qi dysfunction primarily manifest as kidney yang deficiency, insufficient ming fire, and weakened kidney qi, leading to systemic physiological dysfunction, impaired fluid metabolism, disordered spleen and stomach functions, and reduced reproductive functions.① Kidney Qi Instability: Kidney qi instability, also known as lower jiao instability, is a pathological change where kidney qi is weak and unable to contain and store. This often results from aging, congenital weakness, or prolonged illness leading to depletion of kidney qi. Clinically, this is characterized by instability in the reproductive functions, leading to premature ejaculation, incontinence, residual urine, or frequent menstruation, or prolonged menstrual bleeding, or clear leukorrhea, or miscarriage, or chronic diarrhea, or incontinence.② Kidney Not Receiving Qi: Kidney not receiving qi refers to the pathological change where kidney qi is weak and unable to contain lung qi. This often results from overexertion, prolonged illness, or qi not returning to the source, leading to shortness of breath, wheezing, and difficulty in breathing.③ Kidney Yang Insufficiency: Kidney yang insufficiency, also known as kidney yang decline, often results from a weak constitution, prolonged illness, or aging. The impact of kidney yang deficiency on physiological functions primarily manifests as reduced reproductive functions, leading to male impotence, premature ejaculation, and coldness in women leading to infertility; fluid metabolism disorders, leading to edema, frequent urination, or urinary retention; and reduced transformation of food essence, leading to diarrhea and watery stools.(2) Kidney Yin and Essence Dysfunction: This primarily reflects insufficient kidney essence, kidney yin deficiency, and excessive movement of the fire.① Insufficient Kidney Essence: Insufficient kidney essence often results from congenital insufficiency, prolonged illness, or excessive sexual activity. Kidney essence is related to reproductive and developmental capabilities and blood production. Therefore, insufficient kidney essence leads to reduced reproductive functions, such as male infertility and female amenorrhea; developmental disorders in children, such as delayed growth; and early aging in adults, such as hair loss, tooth mobility, tinnitus, forgetfulness, and weakness in the legs.② Kidney Yin Deficiency: Kidney yin deficiency, also known as insufficient kidney water, refers to the deficiency of kidney yin fluids, often resulting from depletion of essence, loss of blood, or excessive consumption of warming and drying substances, or emotional disturbances leading to depletion of essence and blood, or irregular sexual activity, or prolonged illness leading to depletion of true yin. Kidney yin deficiency leads to insufficient nourishment of the body and organs, leading to symptoms such as weakness, dizziness, tinnitus, insomnia, and forgetfulness, or reduced menstruation in women.③ Excessive Movement of Fire: Excessive movement of fire refers to the pathological change where excessive fire leads to premature ejaculation, often resulting from kidney water depletion or liver and kidney yin deficiency. The clinical manifestations include excessive sexual desire, premature ejaculation, and often have the characteristic of upward movement of fire.In summary, kidney pathological changes are often characterized by deficiency rather than excess. Cold is a manifestation of yang deficiency, while heat is a manifestation of yin deficiency. Therefore, the harm of kidney deficiency can be divided into yin deficiency and yang deficiency. Extreme yin or yang deficiency can lead to damage to both, ultimately resulting in both yin and yang deficiency and depletion of essence and qi.3. Relationship between kidney disease and other organs: The kidneys are the foundation of congenital essence, and kidney yin and yang are the roots of the body’s yin and yang. Therefore, when the five zang organs are diseased, prolonged illness will inevitably harm the kidneys, and kidney disease can also easily affect other organs.① Relationship between kidneys and heart, lungs, spleen, and liver: As mentioned earlier, kidney yang deficiency is closely related to the heart, lungs, and spleen, manifesting as heart and kidney yang deficiency, lung and kidney qi deficiency, and spleen and kidney yang deficiency. Conversely, kidney yin deficiency is more closely related to the heart, lungs, and liver, manifesting as heart and kidney yin deficiency, lung and kidney yin deficiency, and liver and kidney yin deficiency.② Relationship between kidneys and bladder: The kidneys and bladder are connected through their meridians. If kidney yang is deficient, the qi transformation function weakens, leading to urinary difficulties; if kidney deficiency leads to insufficient containment, the bladder loses its ability to hold, resulting in urinary incontinence or enuresis. Abnormalities in urine storage and excretion are primarily due to bladder disease, such as bladder damp heat, leading to symptoms such as painful urination, hematuria, and urinary retention. However, the bladder’s storage and excretion functions depend on kidney qi transformation, so abnormalities in urination are related to both the bladder and kidney functions. Clinically, excess conditions are often attributed to the bladder, while deficiency conditions are often attributed to the kidneys. For example, urinary incontinence and polyuria in the elderly are often due to weakened kidney qi.Pathophysiology of the Five Zang Organs (Liver)Pathophysiology of the Liver1. Physiological and pathological characteristics of the liver: The liver is the organ of wind and wood, responsible for regulating and storing blood, with its qi rising and dispersing, preferring to be free and disliking repression. It governs the tendons, opens to the eyes, and is interconnected with the gallbladder. The liver relies on blood for its structure and on qi for its function, embodying the unity of yin and yang. Therefore, its pathological changes are complex and varied, often leading to liver qi stagnation, which can transform into fire, leading to excessive liver yang and internal wind. The liver’s yin blood is also prone to deficiency. Therefore, liver qi and yang are often excessive, while liver blood and yin are often insufficient, which is a significant pathological characteristic of the liver. The liver is known as the thief of the five zang organs, so in addition to its own diseases, it can also affect and involve other organs, leading to complex pathological changes.2. Basic pathological changes of the liver: The pathological changes of the liver can be classified into deficiency and excess, with excess being more common.(1) Liver Qi and Yang Dysfunction: Liver qi and yang dysfunction often manifest as excessive liver qi, liver fire, and excessive liver yang. Excessive liver yang is often due to liver yin deficiency, leading to excessive yang. Therefore, the pathological mechanisms of liver qi and yang dysfunction primarily manifest as liver qi stagnation and liver fire.① Liver Qi Stagnation: Liver qi stagnation, also known as liver depression, is the most common pathological change in liver disease. Emotional stress, repressed emotions, or prolonged illness can lead to liver dysfunction, causing qi stagnation. The pathological characteristics of liver qi stagnation include impaired liver function, leading to stagnation of qi and blood. Clinically, this is characterized by emotional depression, irritability, and symptoms of qi stagnation such as flank and rib pain. The pathological progression of liver qi stagnation includes:First, qi stagnation leads to blood stasis. If qi stagnates, blood will also stagnate. Liver qi stagnation leads to impaired blood flow, resulting in symptoms such as flank pain, abdominal masses, and purple or stasis spots on the tongue. This can affect the Chong and Ren vessels, leading to menstrual irregularities, dysmenorrhea, or amenorrhea in women.Second, qi stagnation leads to phlegm accumulation. Qi stagnation can generate phlegm, which can obstruct the throat, leading to plum pit qi; if it accumulates in the neck, it can lead to goiter.Third, qi stagnation can transform into fire. Excessive qi can lead to fire, and prolonged liver qi stagnation can transform into fire, leading to symptoms of liver fire.Fourth, qi stagnation can affect the spleen and stomach. If liver qi stagnates, it can affect the spleen and stomach’s ability to receive and transform food, leading to symptoms such as vomiting, belching, and abdominal distension.In summary, liver qi stagnation is characterized by impaired liver function and emotional disturbances.② Liver Fire: Liver fire, also known as liver heat, is a pathological change characterized by excessive liver yang. This often results from liver qi stagnation, which transforms into fire, or from excessive anger, leading to excessive liver qi and fire. The main pathological changes include:First, fire disturbs the heart spirit. When fire is excessive, it can disturb the heart spirit, leading to symptoms such as irritability, insomnia, and even delirium.Second, blood circulation is disrupted. When liver fire is excessive, it can lead to rapid blood flow, resulting in symptoms such as palpitations, flushed face, red tongue, and rapid pulse, and even bleeding.Third, liver fire can ascend and descend. Fire tends to rise, and when liver fire ascends, it can lead to symptoms such as red and painful tongue, mouth sores, and if it descends to the small intestine, it can lead to symptoms such as yellow and painful urination.Fourth, excessive heat can lead to symptoms such as fever, thirst, and constipation.(2) Liver Yin and Blood Dysfunction: The dysfunction of liver yin and blood is characterized by insufficient liver yin and blood. When yin is deficient, yang becomes excessive, leading to excessive liver yang and internal wind.① Liver Yin Deficiency: Liver yin deficiency, also known as liver yin deficiency, occurs when the liver is not nourished by kidney water. This can result from kidney yin deficiency, leading to symptoms such as dizziness, dry eyes, flank pain, facial flushing, dry mouth, and five heart heat.② Liver Blood Deficiency: Liver blood deficiency often results from excessive blood loss, prolonged illness, or weakness of the spleen and stomach, leading to reduced blood production. The pathological changes include symptoms of blood deficiency, such as numbness in the limbs, difficulty in joint movement, and poor nail growth, as well as dizziness and blurred vision.③ Excessive Liver Yang: Excessive liver yang often results from liver yin deficiency, leading to excessive liver yang. The pathological changes include symptoms of excessive liver yang, such as dizziness, tinnitus, and weakness in the legs.In summary, liver disease is characterized by the interaction of liver qi stagnation, liver fire, and excessive liver yang. These conditions can lead to complex pathological changes, and the treatment should focus on restoring the balance of liver qi, blood, and yin.In conclusion, the article provides a comprehensive overview of the pathophysiology of the Eight Extraordinary Meridians and their relationship with the twelve regular meridians and the five zang organs. Understanding these concepts is essential for practitioners of Traditional Chinese Medicine in diagnosing and treating various conditions.
