On the Non-ciliated Cells in the Airway Epithelium in Certain Mammals

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The observation was attempted to clarify the more detailed morphological and functional significances of the non-ciliated cells in the airway epithelium of animals. Small-sized mammals such as mice, rats and bats were used in this study, and the non-ciliated cells were usually observed in all over the airway epithelium in these animals.Non-ciliated cells were devided into two different types, i. e., the endocrine type and exocrine type.Endocrine type cells may be identical to the so-called brush cells and other related cells which were initially reported by Rhodin and Dalhamn (1954), on account of their morphological characteristics that are equipped with well-developed filament bundles, glycogen granules and many closely packed micrcvilli protruding from their apical surface into the lumen. All of these type cells generally contained many dense granules of smaller size which were released into the connective tissue layer under the epithelium. No synapse-like contacts between these cells and the intraepithelial nerve fibers were observed.Exocrine type cells were found to exist not only in the terminal bronchioles but in the trachea and other thicker part of the airway epithelium. These cells contained a lot of both types of ER and scarce secretory granules of seromucous in nature. In such animals, neither discernible well-defined glands in the connective tissue layer of the entire airway nor typical goblet cells in the epithelium were observed. Thus, such non-ciliated cells may concern with the production of lubricating material in the epithelium in these animals.