Zang-fu

The zàng-fǔ (simplified Chinese: 脏腑; traditional Chinese: 臟腑) organs are functional entities stipulated by Traditional Chinese medicine (TCM). They constitute the centre piece of TCM's general concept of how the human body works. The term zàng (脏) refers to the organs considered to be yin in nature – Heart, Liver, Spleen, Lung, Kidney – while fǔ (腑) refers to the yang organs – Small Intestine, Large Intestine, Gall Bladder, Urinary Bladder, Stomach and Sānjiaō.

Each zàng is paired with a fǔ, and each pair is assigned to one of the Wǔ Xíng. The zàng-fǔ are also connected to the twelve standard meridians – each yang meridian is attached to a fǔ organ and each yin meridian is attached to a zàng. They are five systems of Heart, Liver, Spleen, Lung, Kidney.

To highlight the fact that the zàng-fǔ are not equivalent to the anatomical organs, their names are often capitalized.

To understand the zàng-fǔ it is important to realize that their concept did not primarily develop out of anatomical considerations. The need to describe and systematize the bodily functions was more significant to ancient Chinese physicians than opening up a dead body and seeing what morphological structures there actually were. Thus, the zàng-fǔ are functional entities first and foremost, and only loosely tied to (rudimentary) anatomical assumptions.

Each zàng-fǔ organ has a yin and a yang aspect, but overall, the zàng organs are considered to be yin, and the fǔ organs yang.

Since the concept of the zàng-fǔ was developed on the basis of Wǔ Xíng philosophy, they're incorporated into a system of allocation to one of five elemental qualities (i.e., the Five Elements or Five Phases). The zàng-fǔ share their respective element's allocations (e.g., regarding colour, taste, season, emotion etc.) and interact with each other cyclically in the same way the Five Elements do: each zàng organ has one corresponding zàng organ that it enfeebles, and one that it reinforces.

The correspondence between zàng-fǔ and Five Elements are stipulated as:

The zàng organs' essential functions consist in manufacturing and storing qì and blood (and, in the case of the Kidney, essence). The fǔ organs' main purpose is to transmit and digest (传化, pinyin: chuán-huà) substances (like waste, food, etc.).

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Wikipedia