Sensory Innervation of the Nasal Cavity of the Sheep

The comparative observation of the nasal mucous membrane of domestic animals has been the object of our study, and in the present work the sensory innervation of the nasal cavity of the sheep was investigated. The ovine nasal cavity was divided into three main parts according to its anatomical structures, namely ventral turbinate, dorsal turbinate, and ethmo-turbinates. KAWATA's silver impregnation method and hematoxylin and eosin stains were applied. 1. The ventral turbinate. Epithelium: The sensory nerve distribution in the epithelium of this turbinate is rather scanty. The sensory nerves terminate in single, unbranched fine strands. The density of the nerve distribution is very poor in part 1, poor in part 2 and moderate in part 3. Lamina propria and submucosa: Various kinds of nerve elements are observed among the vessels and the aggregates of the glands. Sometimes a simple glomerular ending and a single wavy nerve fiber terminal are observed in the layers of part 1 and 2 and more frequently in the layer of part 3. 2. The dorsal turbinate. Epithelium, lamina propria and submucosa: Histologically the ventrall and the dorsal turbinates are roughly homologous to each other. 3. The ethmo-turbinates. Epithelium: Countless olfactory cells are observed in the epithelium of part III, these olfactory cells decrease in number in part II, and the epithelium is composed of ciliated cells and contains almost no olfactory cells in part I. Lamina propria and submucosa: The very fine olfactory nerve fibers projecting from the olfactory cells are collected into bundle, which, as a centripetal nerve fiber, proceeds toward the cribriform plate of the ethmoid bone. The anastomosed of nerve fibers is seen between the tightly packed glands.