POSTNATAL-GROWTH OF RAT LUNG .3. MORPHOLOGY
POSTNATAL-GROWTH OF RAT LUNG .3. MORPHOLOGY
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DOI：
10.1002/ar.1091800109
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发表时间：
1974-01-01
影响因子：
--
通讯作者：
BURRI, PH
中科院分区：
文献类型：
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作者：
BURRI, PH
为研究气体交换器的出生后生长情况，对1、4、7、10、13和21日龄大鼠的肺进行了气管内滴注戊二醛固定。光镜和电子显微镜观察到的形态变化的分析和解释是基于先前对同一材料进行的形态测量和放射自显影的结果。新生大鼠没有肺泡，但呼吸有光滑的壁气道和球囊，分别对应于预期的肺泡管和肺泡囊。肺泡的大部分是在出生时存在的初级隔膜上迅速生长的次生隔膜在第4至13天形成的。这一时期弹性纤维的排列表明，这些纤维可能在间隔突起中起作用。根据超微结构观察，描述了次级隔膜毛细作用的模型。一些证据表明，肺泡也可以由终末细支气管壁的突起形成。初级和次级隔膜最初是未成熟的外观。两者都显示出明显的双毛细血管网络，而成熟的肺泡间隔仅够容纳一根毛细血管。讨论了这种在出生后三周内发生的结构转变的可能机制。
In order to investigate the postnatal growth of the gas exchange apparatus, the lungs of rats aged 1, 4, 7, 10, 13, and 21 days were fixed by intra‐tracheal instillation of glutaraldehyde. The analysis and interpretation of the morphological changes observed by light and electron microscopy were based on the results of previous morphometric and autoradiographic studies performed on the same material.The newborn rat has no alveoli, but breathes with smooth walled air channels and saccules, which correspond to the prospective alveolar ducts and alveolar sacs, respectively. The bulk of alveoli are formed between days 4 and 13 by a rapid outgrowth of secondary septa from the primary septa present at birth. The arrangement of elastic fibers during this period suggests that these may play a role in septal outgrowth. Based on ultrastructural observations a model is described for the capillarisation of the secondary septa. Some evidence is given that alveoli may also be formed by outpouchings in the walls of terminal bronchioles.Primary and secondary septa have initially an immature appearance. They both show an apparently double capillary network, whereas the mature interalveolar septum is just wide enough to accommodate a single capillary. Possible mechanisms for this structural transformation which occurs within three weeks after birth are discussed.