FINE STRUCTURE OF BLOOD VESSELS OF HUMAN NASAL RESPIRATORY MUCOSA

The fine structure of the blood vessels of the human nasal respiratory mucosa was studied with the electron microscope in ten individuals from 16 to 48 years of age, using osmium fixed, Epon embedded material from the lower margin of the inferior and middle conchae. It was found that the subepithelial and periglandular capillaries possessed fenestrated endothelial linings, and that all capillaries were enclosed by porous basement membranes. The venules were lined with a continuous endothelium but the basement membranes of the endothelial tubes and smooth muscle cells showed a high degree of porosity. In the cavernous sinuses, the endothelial basement membrane occurred in the form of a three dimensional lacework mingled with fibrous material. Processes of endothelial cells traversed this lacework at regular intervals, pierced the continuous basement membrane of the musculature and formed appositional junctions with the muscle cell membranes. It appears that the nasal vascular bed is designed for rapid passage of fluid and dissolved substances from the blood vessels to the tissues and vice versa. Furthermore, the porosity of the endothelial basement membrane seems to facilitate the exposure of the contractile elements of the blood vessel wall to agents carried by blood. © 1969, SAGE Publications. All rights reserved.