Bell P B, Stark-Vancs V I
Scan Electron Microsc. 1983(Pt 1):449-56.
This paper reports observations made using scanning electron microscopy (SEM) on the internal structure of the lung of Amphiuma tridactylum. This lung is highly septate at the cranial end, but the septa become gradually reduced in size and number with increasing distance caudally until the septa are reduced to ridges in the wall of the lung. However, there is no respiratory dead space as respiratory epithelium is found throughout the lung. Treatment of isolated lung segments with acetylcholine causes the septa to shorten and thicken which in turn causes the lung diameter to decrease and the alveoli to collapse. These observations are consistent with the hypothesis that the collapse of the Amphiuma lung in vivo, which is responsible for the highly efficient ventilation of the lungs, is brought about by the contraction of pulmonary smooth muscle in the septa and wall of the lung.
本文报道了利用扫描电子显微镜（SEM）对三趾两栖鲵肺内部结构的观察结果。该肺在头端高度分隔，但随着向尾端距离增加，隔膜的大小和数量逐渐减少，直至隔膜在肺壁上变为嵴状。然而，由于整个肺内均发现有呼吸上皮，因此不存在呼吸无效腔。用乙酰胆碱处理分离的肺段会导致隔膜缩短和增厚，进而导致肺直径减小和肺泡塌陷。这些观察结果与以下假设一致：三趾两栖鲵肺在体内的塌陷是由肺隔膜和肺壁中的肺平滑肌收缩引起的，而这种塌陷是肺高效通气的原因。
