[Morphology of the vascular endothelium of the nasal mucosa].

In the nasal mucosa capillaries with fenestrated and continuous endothelium have been described. Fenestrated capillaries are distributed all over the tunica propria. They are increasing in number subepithelially and close to the nasal glands. Particularly subepithelially the endothelial fenestrations are facing the epithelium. This interesting, morphological feature has already been described as "polar differentiation" in capillaries of other tissues and has been interpreted as a functional differentiation. The same observations could be made in muscularised veins of the nasal mucosa. Only a few fenestrations could be detected in the endothelium of these vessels, but they were all facing the adjacent epithelium. The results indicate that the morphological peculiarities of the vascular endothelium of the nasal blood vessels are transient specialisations of this particular type of cells due to different physiological needs.