摘要

The lung parenchyma as a tissue has a rather unusual stress-strain relationship. A theoretical derivation of this relationship is presented which connects the surface tension and the tissue elastic stress in the alveolar septa with the alveolar geometry. The mathematical expression contains a few meaningful physical constants which can be determined by in vitro and in vivo experiments. With this stress-strain relationship, the general equations of lung mechanics are formulated, and solutions to some simpler problems are presented. First, the equilibrium of a lung subjected to a uniform inflation pressure (definition: alveolar air pressure - intrapleural pressure - pleural tension X mean curvature of pleura) is analyzed, and the stability of the equilibrium states with respect to small perturbations is examined. Second, an exact solution for a lung in a chest under the influence of gravity is presented; the solution is "exact," of course, for only a particular lung, but it can serve as a standard to check numerical procedures being developed in many laboratories. Finally, three types of possible atelectasis-planar, axial, and focal-are analyzed. The planar type can exist in a normally inflated lung, provided the layers of alveoli are forced to collapse toward a plane by some external agent. But axial atelectasis (alveoli collapse into a cylinder) can occur only if the dimension (at which the elastic tension in the alveolar septa vanishes). Similarly, focal atelectasis can occur only if the entire lung is smaller than the resting volume.

译文

肺实质作为一个组织有一个相当不寻常的应力应变关系。提出了这种关系的理论推导,它将肺泡间隔中的表面张力和组织弹性应力与肺泡几何形状联系起来。数学表达式包含一些有意义的物理常数,可以通过体外和体内实验来确定。利用这种应力应变关系,建立了肺力学的一般方程,并给出了一些简单问题的解决方案。首先,分析在均匀充气压力 (定义: 肺泡气压-胸膜内压力-胸膜张力 X 胸膜平均曲率) 下的肺平衡, 并且研究了关于小扰动的平衡状态的稳定性。第二,在重力的影响下,给出了胸部肺的精确解; 当然,这个解是 “精确的”,对于特定的肺, 但是它可以作为一个标准来检查许多实验室正在开发的数值程序。最后,分析了三种可能的肺不张 -- 平面、轴向和焦点 --。平面型可以存在于正常膨胀的肺中,前提是肺泡层被某种外力迫使向平面塌陷。但是轴向肺不张 (肺泡塌陷成圆柱体) 只有在尺寸 (肺泡隔中的弹性张力消失) 时才会发生。类似地,只有当整个肺小于静息体积时,才会发生局灶性肺不张。

Atelectasis

呼吸 肺萎陷 疾病
概述  :  

肺不张又称肺萎陷,是指全肺或部分肺呈收缩和无气状态。肺不张不是一个独立的疾病,而是支气管、肺、胸膜等疾病较常见的并发症之一。任何原因,凡是能引起气道阻塞、肺组织受压以及肺表面活性物质减少,肺泡表面张力增高的疾病均可引起全肺或肺叶、肺段、亚肺段的肺组织含气量减少、体积缩小,形成肺不张。 分类肺不张有多种分类方法,按发病机制可分为阻塞性肺不张(又称吸收性肺不张)、压缩性肺不张、纤维性肺不张(又称瘢痕收缩性肺不张)、反射性肺不张及弥漫性肺泡不张(又称透明膜病);按病因可分为癌性肺不张、结

Atelectasis   英 /,ætɪ'lektəsɪs/   美  /,ætə'lɛktəsɪs/

释    义   n. 肺不张;(出生时肺的)膨胀不全

例    句   Mycoplasma pneumonia can supervene with atelectasis. 支原体肺炎可并发肺不张。

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