The five zang-organs include the heart, the lung, the liver, the spleen and the kidney. The following is a brief description of the physiological functions of the five zang-organs and their relationships with the body, the organs and the orifices. The latter includes three aspects, i.e. the relationships of the five zang-organs with the five constituents, the organs that the five zang-organs open into and the focal external manifestations of the five zang-organs.The five constituents include the vessels, the skin, the tendons, the muscles and the bones that are dominated by the five zang-organs respectively.

The orifices, simplification for "the five sensory organs and the nine orifices", include the tongue, the nose, the eyes, the mouth, the ears, the external genitals and the anus. The heart, the lung, the liver and the spleen govern one orifice respectively. But the kidney opens into the ears, the external genitals and the anus. The focal external manifestations of the five zang-organs refer to five special areas (i. e. the face, the body hair, the nails, the lips and the hair) on the surface of the body on which the essence of the five zang-organs displays.