Sasaki H, Hoppin F G, Takishima T
J Appl Physiol Respir Environ Exerc Physiol. 1978 Dec;45(6):858-69. doi: 10.1152/jappl.1978.45.6.858.
To characterize the stresses which determine bronchial diameter in the lung, we estimated peribronchial pressure (Px) relative to intrabronchial pressure (Pbr) and to alveolar pressure (PA) for the main lobar bronchus of excised dog lobes using the technique of Takishima et al. (J. Appl. Physiol. 38: 875--881, 1975). The recoil of the bronchial wall, Pbr---Px, when smooth muscle was relaxed varied primarily with bronchial diameter. The recoil of the parenchyma around the bronchus, Px---Pa, varied with lung volume but was also diameter-dependent and served to double approximately the effective elastance of the bronchus in situ. We estimated recoils during slow deflations from TLC with the bronchus untreated, or pharmacologically contracted or relaxed. In untreated and relaxed states, local parenchymal and bronchial recoils were of similar magnitude to overall lung recoil (i.e., Px congruent to Ppl) except at high inflating pressure (PA -- Ppl = 30 cmH2O) where they were about half as great. With contraction, bronchial and local parenchymal recoils increased to as much as twice overall lung recoil. Contracted smooth muscle exerted a radial stress of 36+/-14 cmH2O at full lung inflation but much less during stepwise deflation.
为了描述决定肺内支气管直径的应力，我们采用Takishima等人（《应用生理学杂志》38: 875 - 881, 1975）的技术，估计了切除的犬肺叶主叶支气管的支气管周围压力（Px）相对于支气管内压力（Pbr）和肺泡压力（PA）的情况。当平滑肌松弛时，支气管壁的回缩力，即Pbr - Px，主要随支气管直径而变化。支气管周围实质组织的回缩力，即Px - Pa，随肺容积而变化，但也与直径有关，并且在原位使支气管的有效弹性大约增加一倍。我们估计了在从肺总量缓慢放气过程中，支气管未经处理、经药物收缩或松弛时的回缩力。在未经处理和松弛状态下，局部实质组织和支气管的回缩力与整个肺的回缩力大小相似（即Px与胸膜腔内压Ppl相等），但在高充气压力（PA - Ppl = 30 cmH2O）时，它们约为整个肺回缩力的一半。在收缩状态下，支气管和局部实质组织的回缩力增加到整个肺回缩力的两倍之多。在肺完全充气时，收缩的平滑肌施加的径向应力为36±14 cmH2O，但在逐步放气过程中则小得多。
