ABSTRACT
The vomeronasal organ [VNO] is a chemosensory structure involved in the detection of pheromones in most mammals. Light microscopic and ultrastructural techniques were used to study the morphological structure of the rat VNO in Ten adult male albino rats. Two types of epithelium have been distinguished in the rat vomeronasal organ: Sensory and nonsensory epithelium. At the light microscopical level, distinctive morphological features can be distinguished which illustrate important differences between the two types of epithelia e.g. The Sensory epithelium is thicker than the nonsensory epithelium. Sensory epithelium containing 3 types of cells: supporting cells [SCs], vomeronasal receptor neurons [VRNs] and basal cells [BCs]. nonsensory epithelium containing 2 types of cells: columnar ciliated and basal cells. The differences between the two epithelial layers become more obvious at the electron microscopical level. Compound tubuloacinar vomeronasal glands are observed in submucosa of the vomeronasal epithelium. Their cytoplasm contains secretory granules of different electron density. The presence of nerve terminals contacting glandular cells suggests participation of the nervous system in the regulation of the secretory activity of the vomeronasal glands. Understanding the ultras tructural results of the tissue components of this vomeronasal Organ may shed light on its function