根据世界保健机构的定义,老人肺系指未引起肺泡壁或细支气管破坏的细支气管、肺泡道、肺泡囊偏向扩大。这只是从形态解剖学做出的定义。高度的老人肺其扩张(ductectasis)程度近似于全小叶型的慢性肺气肿;但在肺泡领域内没有破坏,此点可与肺气肿相区别。其中肺泡道扩张,在组织学方面已见到向全细叶性肺气肿移行。 According to the definition of the world’s health care institutions, the elderly pulmonary system refers to the bronchioles that cause no damage to the alveolar wall or bronchioles, the alveolar passage, and the enlargement of the alveolar sac. This is just a definition made from morphological anatomy. The degree of ductectasis in elderly persons with high altitude is similar to that of whole-lobe-type chronic emphysema; however, there is no disruption in the area of ​​the alveoli, which can be distinguished from emphysema. One of the alveolar ducts in histology has been seen to all-lobe emphysema migration.