THE ROLE OF FENESTRATED VESSELS FOR THE SECRETORY PROCESS IN THE NASAL-MUCOSA - A HISTOLOGICAL AND TRANSMISSION ELECTRON-MICROSCOPIC STUDY IN THE RABBIT

Both nasal glands and nasal vessels are supposed to be responsible for the humidification of inhaled air. After previous studies on the vasc ulature of the nasal septal mucosa in the rabbit, we examined vessels of the anterior concha in order to find a morphological equivalent to explain the role of endonasal vasculature in the secretory process of this tissue. The main findings of our study include the detection of f enestrated endothelial walls of both capillaries and venous sinuses lo cated underneath and directly adjacent to the basal cell layers of the epithelium. The same phenomenon-fenestrated vessels underneath the ep ithelium with the fenestrated parts facing the epithelial cells - has been described in other parts of the body and has been called ''polar differentiation.'' In accordance with the interpretations of other aut hors, we conclude that these features are responsible for the regulati on of endonasal fluid exchange.