Electron microscopic and functional aspects of the human vomeronasal organ

The vomeronasal organ or Jacobson's organ is essential for pheromone detection and reproductive behavior in most mammals. The purpose of this article is to describe the fine structure of the adult human vomeronasal organ in 14 specimens and to discuss functional aspects. Our studies show a duck-like invagination of the epithelium, surrounded by numerous exocrine glands with short ducts; their fine structure suggests serous secretion. In the depth of the invagination, pseudostratified columnar epithelial cells are seen, with plump processes, kinocilia, and microvilli at the apical cell membrane. There are several cell types that differ regarding their organelles and electron density; the light sensory cells exhibit neurofilaments. Underneath the typical basement membrane, in the very vascular lamina propria, numerous myelinated and unmyelinated axons are present. These morphologic findings, which are unique in the human body, suggest that a chemosensory epithelium corresponding to a vomeronasal organ may exist. Its central connections and the possible functional significance for pheromone detection are unknown. Preservation of the vomeronasal organ in endonasal surgery could become important both clinically and medicolegally, should function be demonstrated in humans.