What organ governs water metabolism?

The kidney is the organ primarily responsible for governing water metabolism in the body. It plays a crucial role in regulating the body's fluid balance by filtering blood, reabsorbing water, and excreting waste products in the form of urine. This process ensures that the body maintains an appropriate levels of hydration and electrolyte balance, which are vital for overall health.

In Traditional Chinese Medicine (TCM), the kidneys are viewed not only as organs for detoxification and waste elimination but also as reservoirs of vital energy (or "essence") needed for various bodily functions, including those related to water metabolism. They are believed to control the distribution and balance of fluids within the body, influencing everything from urination to the hydration of tissues.

While other organs like the heart, lung, and spleen play important roles in overall health and can influence the body's fluid balance indirectly, it is the kidneys that have the primary role in water metabolism. The heart is associated with blood circulation, the lungs with respiration and the exchange of gases, and the spleen with digestion and the transformation of food into energy. Each of these organs contributes to overall homeostasis but does not govern water metabolism in the way the kidneys do.