Regional variation in respiratory epithelium of the nasal cavity of the bandicoot (Isoodon macrourus).

The non-olfactory ciliated epithelium of the nasal cavity was investigated in the bandicoot (Isoodon macrourus), a small ground-dwelling marsupial. Two distinct epithelial types were identified and designated conchal and septal. Conchal epithelium is non-secretory. It covers most of the naso- and maxilloturbinates, the lateral nasal wall, and part of the maxillary sinus. Septal epithelium contains mucus-secreting goblet cells. Rostrally, it covers the nasal septum and mid-ventral floor of the nasal cavity. Further caudally it lies on the ventral part of the septum and ventrally facing parts of naso- and ethmoturbinates. It corresponds closely to most published descriptions of respiratory epithelium. Ciliated and basal cells are common to both types. Conchal epithelium has a nonciliated domed cell with a rounded surface projecting into the ciliary border. This epithelium has a rich innervation and axon terminals are frequent almost to the cell surface. Septal epithelium contains goblet cells whose appearance varies according to secretory activity, and two rarer cells of unknown function, brush and pale cells, which are also seen in the olfactory epithelium of the bandicoot.