In Chinese medicine the Heart regulates the flow of Blood. Disharmonies of the Heart are often revealed in the condition of the tongue and/or the face. The Heart stores Shen, one of the fundamental substances which may be loosely equated with vital spirit, and clear healthy Shen is often recognized as sparkle or light in the eye. When the Shen-storing of the Heart is impaired, symptoms of deficient Shen may arise, such as unbalanced feelings, unclarity of speech, insomnia, excessive dreaming or forgetfulness. In more extreme cases there may appear serious mental disorders.
The Heart is called the "Fire Prince", the highest ruler of the Organs. It is seen as the centre of consciousness, feelings and thoughts. The Heart is the lower of the two houses of Shen. The higher house is the third eye, or forehead chakra, where it brings forth clarity of thoughts and a conscious life direction.
The Pericardium, the 'heart governor' is also an Organ of Fire Yin. The Pericardium is paired with its Yang Organ, the Triple Burner, and the Heart with the Small Intestine.