Discussions of the zang-and-fu-viscera are expounded through a combination of physiology and pathology. When pathological changes are involved, it usually results in a change in physiological functions which deduce pathological manifestations. This in turn refutes the western belief of the similarity between physiological functions and pathological changes. Chinese medical theory believes that the two are not formed independently of each other and work simultaneously together.

Zang-and-fu-viscera in traditional Chinese medicine are considered not only anatomi-cal units, but also conceptually are a part of the body's physiology and pathology. During the initial formation stage of the visceral manifestation theory, the main focus of attention was aimed at observing the external symptoms and signs of physiological functions and pathological changes. It was less geared towards observation of the morphology of the viscera. Therefore the modern name for the organs, heart, lung, spleen, liver, kidney, are utilized in TCM today. However, the explanations of their physiological functions are widely different from those of modern medicine. The description of the function of a viscus in TCM's philosophy may include that of several organs if applied in the context of modern medical theory, the reverse being true in the opposite case. Hence, the viscera in TCM is characterized by multifunction. For example, the heart in TCM theory refers as well to some of the functions of the nervous system, while also referring to the functions of the heart in modern medicine. The functions of the central nervous system in modern medicine are closely related to that of a number of viscera in TCM, those being the heart, liver, spleen, lung, kidney and gallbladder.