Iovannitti B, Pirie H M, Wright N G
Res Vet Sci. 1985 Jan;38(1):80-7.
The surface characteristics of the lower respiratory tract of two groups of cattle were studied with the scanning electron microscope. Group A comprised six one-week-old calves and group B four adult cows. None of the animals had overt respiratory disease or gross morphological evidence of pulmonary lesions. The trachea, bronchi, bronchioles and alveoli of the cranial and the caudal lobes of the right lung were examined. In both groups the luminal surface of the trachea and large bronchi were completely covered by cilia, apparently forming an efficient mucociliary escalator. In the adult animals there were some patchy areas in the trachea and large bronchi devoid of ciliated cells; these were considered abnormal. In the bronchi, non-ciliated cells, mainly mucus-secreting, were not easily identified unless they were discharging secretion. In small bronchi, non-ciliated cells were more evident and easily seen. The bronchioles had many non-ciliated cells and very few ciliated cells capable of forming a complete carpet for a mucociliary escalator. Types 1 and 2 alveolar epithelial cells and alveolar macrophages were identified in both groups. Pores of Kohn were found in the alveolar walls in all animals.
用扫描电子显微镜对两组牛的下呼吸道表面特征进行了研究。A组由6头1周龄的犊牛组成，B组由4头成年母牛组成。所有动物均无明显的呼吸道疾病或肺部病变的大体形态学证据。检查了右肺头叶和尾叶的气管、支气管、细支气管和肺泡。两组中，气管和大气管的管腔表面均完全被纤毛覆盖，显然形成了一个有效的黏液纤毛清除系统。在成年动物中，气管和大气管有一些没有纤毛细胞的片状区域；这些被认为是异常的。在支气管中，除非正在分泌分泌物，否则主要分泌黏液的无纤毛细胞不易识别。在小支气管中，无纤毛细胞更明显且易于观察到。细支气管有许多无纤毛细胞，而能够形成完整黏液纤毛清除系统覆盖层的纤毛细胞很少。两组均识别出1型和2型肺泡上皮细胞以及肺泡巨噬细胞。所有动物的肺泡壁中均发现了孔氏孔。
