Masu M, Okada S
Department of Anatomy, Osaka Dental University, Japan.
Okajimas Folia Anat Jpn. 1994 May;71(1):35-49. doi: 10.2535/ofaj1936.71.1_35.
Ultrastructure and microvascular pattern of the parotid duct (main excretory duct) in the cat were investigated by TEM and SEM. The duct was lined by a pseudostratified epithelium which was surrounded by a double-layered vascular sheath. Three kinds of principal cells were observed in this epithelium--tall columnar, light and basal cells. The tall columnar cells did not bear basement membrane specialization (infoldings) but well-developed lateral interdigitations. Microvilli were present on their luminal surface. Basal infoldings and lateral interdigitations did not develop in the light cells. Basal cells were located on the basement membrane of the epithelium. The basal surface of the duct epithelium was studded with half-desmosomes. The external sheath of the double-layered vascular sheath was composed of arterioles and venules, and the inner sheath was formed by a capillary network immediately beneath the epithelium. Meshes of the capillary network in the collecting ducts and the region of origin appeared round and in the superficial and deep regions became elongated along the duct axis. It can be concluded that the parotid duct in the cat not only transports the saliva into the oral cavity, but also actively builds up the primary saliva to the final saliva, owing to absorptive and secretory functions which were made by an important contribution of the double-layered vascular sheath surrounding the whole length of the duct.
通过透射电子显微镜（TEM）和扫描电子显微镜（SEM）对猫腮腺导管（主要排泄管）的超微结构和微血管模式进行了研究。导管内衬假复层上皮，其周围有双层血管鞘。在该上皮中观察到三种主要细胞——高柱状细胞、亮细胞和基底细胞。高柱状细胞没有基底膜特化（内褶），但有发达的侧向指状突。其腔面有微绒毛。亮细胞没有基底内褶和侧向指状突。基底细胞位于上皮的基底膜上。导管上皮的基底表面布满半桥粒。双层血管鞘的外层由小动脉和小静脉组成，内层由紧邻上皮下方的毛细血管网形成。集合管和起始区域的毛细血管网网眼呈圆形，在浅层和深层区域则沿导管轴伸长。可以得出结论，猫的腮腺导管不仅将唾液输送到口腔，而且由于围绕导管全长的双层血管鞘的重要作用所产生的吸收和分泌功能，还能将初级唾液积极地转化为终末唾液。
