[Electron microscopy studies of the human vomeronasal organ]

The vomeronasal organ, or Jacobson's organ, is essential for pheromone detection and reproductive behavior in most mammals. In humans, it has been described as a blind diverticulum in the anterior nasal septum, but without a documented function. The purpose of this study is to describe the fine structure of the human adult vomeronasal organ in 14 specimens. Our studies showed a duct-like invagination of the epithelium that was surrounded by numerous exocrine glands with short ducts. The fine structure of these glands suggested a serous secretion. In the depth of the invagination, pseudostratified columnar epithelial cells were seen that had plump processes, kinocilia and microvilli at the apical cell membrane. Several cell types were seen that differed regarding their organelles and electron density, with light sensory cells exhibiting neurofilaments. Underneath the typical basement membrane, numerous myelinated and unmyelinated axons were present in the very vascular lamina proprion. These morphological findings are unique in the human body and suggest that a chemosensory epithelium corresponding to a vomeronasal organ may exist. Its central connections and the possible functional significance of this tubed organ for pheromone detection are unknown and need further study.