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Ultrastructure of the microvessels of the iris in mammals with special reference to their permeability

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Summary

The ultrastructure of the microvessels of the guinea pig, rat, rabbit and cat iris was studied in an effort to discover the morphological basis of the permeability of the iris vessels. The microvessels of the iris revealed a non-fenestrated endothelium. A relatively wide intercellular space and macula occludens were seen at the intercellular junctions of the endothelial cells in the capillaries and postcapillary venules. It is concluded that these intercellular spaces may form the small pore system which makes the diffusion through the iris vessels possible. Transcapillary exchange of high molecular substances is made possible by the vesicular transport system of the micropinocytosis vesicles.

Zusammenfassung

Es wurde die Ultrastruktur der kleinen Blutgefäße in der Iris des Meerschweinchens, der Ratte, des Kaninchens und der Katze untersucht, um die morphologische Grundlage für ihre Permeabilität zu finden. Sie verfügen über ein nicht gefenstertes Endothel. An den intercellulären Verbindungen der Capillaren und postcapillären Venolen fallen relativ weite Zwischenräume und eine Macula occludens auf. Hierin ist das enge Porensystem zu sehen, welches den Stoffaustausch durch die Irisgefäße erlaubt. Den Durchgang höher molekularer Substanzen durch die Capillaren ermöglicht ein vesiculäres Transportsystem in Form der Mikropinocytose.

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Authors and Affiliations

  1. University Eye Clinic, Oulu

    M. Saari

  2. The Electron Microscope Laboratory, University of Helsinki, Finland

    M. Saari

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  1. M. Saari
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Additional information

Paper read in the meeting of the European Club for Ophthalmic Fine Structure in London April 19, 1974.

Supported by a grant from the Finnish Medical Foundation and the Instrumentariumin Tiedesäätiö Foundation.

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Saari, M. Ultrastructure of the microvessels of the iris in mammals with special reference to their permeability. Albrecht von Graefes Arch. Klin. Ophthalmol. 194, 87–93 (1975). https://doi.org/10.1007/BF00413372

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  • DOI: https://doi.org/10.1007/BF00413372

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