What does basic TCM theory describe?
The basic theories of Traditional Chinese Medicine (TCM) describe physiology and pathology of the human body, disease etiology, diagnosis, and differentiation of symptom-complexes. These include, but not limited to, the theory of Yin-Yang, Five Elements, Zang-fu (organs), Channels-collaterals (blood vessels), Blood and Qi, body fluid, and methods of diagnosis.
Fundamental theories in TCM include two outstanding features- holistic point of view, and application of treatment according to the differentiation of symptom-complexes. According to these theories, Zang-fu (organs) are the core of human body as an organic entity in which tissues and organs are connected through a network of meridians/channels and collaterals (blood vessels). This concept is applied extensively to all aspects of TCM, including physiology, pathology, diagnosis, and treatment.
The functional physiological activities of the Zang-fu (organs) are dissimilar, but they work in coordination. There exists an organic connection between organs and their related tissues. Pathologically, dysfunction of the Zang-fu (organs) may be reflected on the body surface through the channels and their collaterals (e.g. pimples on skin or canker sores in mouth). Meanwhile, diseases of surface tissues of the body may also affect their related Zang-fu (organs). Affected Zang-fu (organs) may also influence each other through internal connections. TCM treatment consists of regulating functions of the Zang-fu (organs) in order to correct pathological changes. With the help of acupuncture, treatment can also be accomplished by stimulating certain areas of the external body.
Edited from http://tcmbasics.com/