山羊胎期肺的组织发生

研究了山羊胎期肺的组织发生 ,将肺的发育分为 5个时期 :1胚胎期 (3～ 5周 ) ,肺芽分支形成主支气管 ,主支气管长度不断增长并萌芽出叶支气管 ,均衬以假复层柱状上皮 ;2腺状期 (6～ 12周 ) ,以支气管树发育为主 ,小支气管及终蕾衬以假复层和 /或单层柱状上皮 ;3小管期 (13～ 14周 ) ,以呼吸部发育为主 ,原始肺泡开始形成 ,呼吸性细支气管和原始肺泡衬以未分化的立方上皮 ;4囊状期 (第 15周 ) ,呼吸部发育显著 ,肺内细支气管及其末端呈现出“充气”状态 ;5肺泡期 (16～ 2 2周 ) ,以肺泡的形成和分化为主 ,肺泡上皮分化为扁平的肺泡 型细胞和立方形的肺泡 型细胞

Histogenesis of the goat lung

50 goat embryoes and/or fetal lungs were observed with LM which showed the embryologic,pseudoglandular,canalicular,saccular and alveolar stages during their development.1．Embryologic stage(3-5wks):The lung bud branching and forming into the two principal bronchi,the principal bronchi growing in length and budding lobar bronchi lined with seudostratified columnar epithelium.2.Pseudoglandular stage(6-12wks):The bronchial divisions were differentiated and their air conducting system became established,lined with seudostratified and/or single-walled columnar epithelium.3.Canalicular stage(13-14wks):The respiratory bronchioles developed quickly，the primitive alveoli had developed,the respiratory bronchioles and primitive alveoli were lined by cuboid cells.4.Saccular stage (15wk):The respiratory divisions developed dramatically,the lung assumed a more “aerated” appearance.5.Alveolar stage (16-22wks):The alveoli developed and differentiated into flattened(type Ⅰ cell)and cuboid (type Ⅱ cell)epithelial cells.