In western medicine, the body's organs are explained in terms of their anatomical structure and physiological functions. However, in Traditional Chinese Medicine (TCM), the approach is quite different. Organs are considered functional units of the body. Therefore, what is typically thought of as an organ (i.e. heart, liver, stomach etc.) has a much broader meaning and application in TCM. An organ's anatomical structure is not as important as its yin yang properties or relationships with other organs. Chinese medicine recognizes five yin organs and six yang organs, also known as "zang" and "fu" organs respectively.

What are the yin yang organs?

The yin organs include the liver, heart, spleen, lungs and kidneys. The pericardium is sometimes considered a sixth yin organ. The function of the yin organs is to produce, transform, regulate and store fundamental substances such as qi, blood, and body fluids. In general, yin organs do not have empty cavities.

The six yang organs are made up of the gall bladder, stomach, small intestine, large intestine, bladder and triple burner. The triple burner does not have a physical structure and is considered a functional unit. The yang organs are mainly responsible for digesting food and transmitting nutrients to the body. Usually, yang organs are organs with empty cavities.

In TCM, the physiological functions of the body are based on harmonious relationships between yin and yang organs. Central to these relationships is the interior and exterior relationship theory, which states the interior belongs to yin and the exterior belongs to yang. Hence, yin organs are thought to have more internal functions and are called interior organs. They tend to play a more important role in TCM medical theory and practice. The yang organs, on the other hand, are believed to have more external functions and are considered exterior organs.