In Chinese medicine theory

heart and small intestine

lung and large intestine

spleen and stomach

kidney and urinary bladder

liver and gallbladder as well as pericardium and Sanjiao （triple energizer） are in the exterior-interior relationships and influence each other both physiologically and pathologically.The communication and contact between meridians and channels build the basic framework of the exterior-interior relationship between Zangorgans and Fu-organs.Qi

blood

essence

thin and thick fluids are the basic materials to fulfil the exterior-interior function.In recent years

the results of modern research confirmed the scientific connotation of this mutual relationship from the anatomical physiology

histology and embryology.The field of lung and large intestine as well as heart and small intestine has made significant progress.