The two dirties closely related to the ascending and descending of Qi are

The two zang-fu organs closely related to the ascending and descending of Qi are lung and liver.

Most organs located in the body cavity communicate directly or indirectly with the outside world, including digestive system, respiratory system, urinary system and reproductive system. According to its morphological structure, it can be divided into lumen organs and parenchymal organs. The lumen organs are connected with the outside world through pipelines; The parenchymal organs are mainly glands, and there are catheter openings on the wall of the lumen organs.

From the perspective of individual development, most digestive and respiratory systems are derived from endoderm; The respiratory organ is another tube protruding from the upper part of the primitive digestive tube to the ventral side. The urinary and reproductive organs originated from the urogenital ridge of mesoderm and evolved into urinary and reproductive systems with different functions, but men still have a common excretory duct.

The digestive tract of human body is long and tortuous, including mouth, pharynx, esophagus, stomach, small intestine, large intestine and anus. The small intestine is the longest and the most important place to digest and absorb nutrients, with a total length of 5~7 meters. It is coiled in the middle and lower part of abdominal cavity and divided into duodenum, jejunum and ileum in turn. The length of the duodenum is about 12 fingers together, about 25~30 cm.

Because the lumen receives acidic chyme, pancreatic juice and bile propelled by the stomach, some people call the duodenum the "Yangtze River Delta" of the digestive system. There is no obvious boundary between jejunum and ileum, jejunum accounts for 2/5 and ileum accounts for 3/5. The large intestine is connected with the back of the small intestine, with a total length of 1.5 m, and is divided into three parts: cecum, colon and rectum.