The kidneys are vital organs responsible for the growth, reproduction, and maintenance of the body's metabolic balance of water. Additionally, they store pure substances inherited from one's parents, making them an innate source of life. The formation of the fetus is believed to begin in the kidneys, which are formed before the body itself, making them the roots of the viscera, bowels, and 12 meridians. Clinical practice shows that treating the kidneys can address cases of slow growth of an innate nature. The kidneys yin (true yin or kidney water) and kidney yang (true yang or life door-fire) are responsible for storing pure substances, which refer to both those of the five viscera and six bowels derived from water and grains digested and transformed by the spleen, as well as those of the kidneys themselves, closely related to human reproduction, growth, and aging. Insufficient pure substances in the kidneys can cause infertility, slow growth, and premature aging, requiring toning up of the kidneys.
The regulation of body fluids is closely related to the lungs, spleen, and kidneys, which are responsible for energy transformation of the triple burning space, initiated by the kidneys yang. The kidneys also affect the growth and softness or hardness of bones, treating soft bones in children, and weak legs in adults. Marrow nourishes bones and gathers in the brain, making it the "sea of marrow," which is generated by pure substances stored in the kidneys. Kidney energy deficiency, a common syndrome, may cause low intelligence, slow movements, and soft bones. Acupuncturists apply the kidney point in auricular acupuncture to treat incomplete growth of the cerebrum in children and the aftereffects of brain concussion, while Chinese herbs that tone up the kidneys treat aplastic anemia.
The heart and kidneys maintain balance and control each other, relying on mutual adjustment of yin and yang, or communication between the upper and lower organs. The heart yang relies on the kidneys yin for its supply of yin energy, while the kidneys yin relies on the heart yang for its supply of yang energy. When the heart or the kidneys are disordered, disrupting the normal relationship between the two organs, insomnia, palpitations, forgetfulness, lumbago, and seminal emission can occur.
The liver stores blood, while the kidneys store pure substances, which can generate and transform each other. The kidneys yin nourishes and waters the liver yin under normal circumstances, but when the kidneys suffer from yin deficiency, liver yin deficiency and liver yang upsurging can occur. Yin deficiency of the liver can also cause yin deficiency of the kidneys, leading to lumbago, dizziness, and being hasty and jumpy.
The kidneys and bladder are connected through meridians and form a yin-yang relationship, with the energy of the kidneys affecting the bladder's capacity for urination.