The Internal Organs
The internal organs consist of the five viscera and six bowels. The five viscera are the liver, heart, spleen, lungs, and kidneys. The Yellow Emperor's Classics of Internal Medicine explains that the heart is connected to the blood vessels, and its condition is reflected in the complexion, with the kidneys as its master. The lungs are linked to the skin, and their condition is reflected in the hair, with the heart as their master. The liver is connected to the tendons, and its condition is reflected in the nails, with the lungs as its master. The spleen is linked to the muscles, and its condition is reflected in the lips, with the liver as its master. The kidneys are connected to the bones, and their condition is reflected in the hair on the head, with the spleen as their master. In this context, "master" refers to the controlling element in the five-elements theory, and "prosperity" refers to the manifestation of good health on body surfaces such as hair, ears, or nose.
The six bowels include the gallbladder, small intestine, stomach, large intestine, bladder, and triple burning space. The Yellow Emperor's Classics of Internal Medicine explains that the stomach, large intestine, small intestine, triple burning space, and bladder are the five organs generated by the energy of the Heaven, and their energies resemble the energy of the Heaven. These organs drain things off without storing them up, and they receive turbid energies from the five viscera. They are known as transmitting bowels because they cannot store things up for long and have to drain things off in due course. The anus acts as the messenger for the five viscera and drains off water and grains without storing them up for long.
The five viscera store up pure energy without draining off and, therefore, can be filled to capacity but cannot be oversupplied. In contrast, the six bowels transmit things without storing them up, and they may be oversupplied but cannot be filled to capacity. After foods enter through the mouth, the stomach will be full, but the intestines will still be empty. Therefore, the bowels may be oversupplied but cannot be filled to capacity, and the viscera may be filled to capacity but cannot be oversupplied.
The Heart
The Small Intestine
The Liver
The Gallbladder
The Spleen
The Stomach
The Lungs
The Large Intestine
The Kidneys
The Bladder
The Pericardium
The Triple Burning Space
The Brain, Marrow, and Womb