Zang-fu

I. THE ZANG ORGANS -> Kidney

The kidney locates at either side of the lumbus. Its channel connects with the urinary bladder, with which it is externally-internally related. It opens into the ear. Its main physiological functions are (1) storing essential substances and dominating human reproduction, growth and development; (2) producing marrow which collects in the head forming the brain, dominating the bones and manufacturing blood; (3) dominating body fluid, and (4) receiving qi (air).

(1) Storing essence and dominating reproduction, growth and development. The essence in the kidney, also referred to as the yin of the kidney, consists of two parts: congenital essence inherited from the parents and acquired essence transformed from the essential substances of food. The vital essence of the kidney is an important aspect of the qi (vital functions) of the kidney, greatly influencing the function of the kidney in reproduction, growth and development. Neijing gives a precise description of the physiological function of the kidney in the process of birth, growth, full development and senility: At the age of about 14 for women and 16 for men, the qi of the kidney flourishes. Women will have the onset of menstruation, and men will have seminal emission both signifying the power of reproduction. When women reach the age of 28 and men around 32, the qi of the kidney is at its height, the body grows and develops, reaching the prime of life. When women reach the age of 49 and men around 64, the qi of the kidney starts to decline, the body begins to wither and at the same time the function of reproduction gradually fails.