Different Cell Types In the Lower Respiratory Tract of the Reindeer {Rangifer tarandus tarandus L.)- A Transmission Electron Microscopical Study

Abstract: The epi thel ium of the trachea and distal airways of 12 healthy adult reindeer were studied w i t h transmission electron microscopy. The ultrastructure of the reindeer respiratory tract corresponded to the findings of previous inve-stigators studying other mammalian species. The epithel ium of the trachea and bronchi, down to the level of the distal bronchiol i, was composed of three main types of cell: ci l iated, goblet, and basal. In the distal brochioli, non-ciliated cells similar to those known as Clara cells were predominant. Numerous electron-dense granules and the cell organelle pattern resembled the Clara cell type observed in laboratory rodents, rabbit, sheep, p i g, horse, and llama. Pneumocyte 1 and pneumocyte 2 cells were readily identified in the alveoli. The pneumocyte 2 cells possessed short m i c r o v i l l i and granules w i t h lamellar content. Micropinocytot ic vesicles were very numerous i n the alveolar w a l l, and a small number of alveolar macrophages occasionally seen i n the alveolar lumen. K e y w o r d s: Bronchial epithelium, pulmonary epithelium, ultrastructure, Clara cell, T E M, lung. Rangifer, 17 (2): 73-8