Arterial supply of the choriocapillaris of anuran amphibians (Rana temporaria, Rana esculenta)

Abstract

The pattern of the vascular supply to the choroid of the frog eye was studied in toto with the use of the injection-replication-SEM technique. The choroid of anuran amphibians is composed mainly of the choriocapillaris. In both species studied (Rana temporaria, Rana esculenta), an independent arterial supply to the choriocapillaris supplemented that from the ciliary arteries. This additional vascular route arises from the optic artery, a separate branch of the arteria infundibularis superficialis. The optic artery, accompanied by its vein within the vascular sheath of the optic nerve, joins the rich arterial capillary network of the choriocapillaris and supplies the posterior pole of the ocular bulb. The superficial capillary network displays a dense collar around the entrance of the optic nerve into the eye and is composed of a circular meshwork of small capillaries, several layers deep. More peripherally, however, it becomes a single layered. This capillary network, as a whole, establishes numerous connections with the adjacent choriocapillaris at the posterior pole of the ocular bulb. In anuran amphibians the complex arrangement of both arterial systems supporting the choriocapillaris may be regarded as a more complete equivalent of the short posterior ciliary arteries of mammals.

Ocular microvasculature in adult Xenopus laevis: Scanning electron microscopy of vascular casts

“…chc, choriocapillaris; civ, ciliary vein; hyv, hyaloid vein; ia, iridial artery; iv, iridial vein; nbhya, nasal branch of hyaloid artery; nbia, nasal branch of iridial artery; tbhya, temporal branch of hyaloid artery; tbia, temporal branch of iridial artery; vr, vasa recta. From the seven vascular castings done, none was that complete and structurally that well preserved as those published by Miodoński and Bär (1985, 1987a, 1987b, 1989. Our best-preserved vascular casts revealed spatial distortions; others were incompletely filled.…”

“…From the seven vascular castings done, none was that complete and structurally that well preserved as those published by Miodoński and Bär (1985, 1987a, 1987b, 1989). Our best‐preserved vascular casts revealed spatial distortions; others were incompletely filled.…”

“…Our best‐preserved vascular casts revealed spatial distortions; others were incompletely filled. Regrettably, Miodoński and Bär (1985, 1987a, 1987b, 1989) did not report how many of their castings resulted in spatially so well‐preserved vascular castings. The composite findings, however, enabled us to compare our results with those gained by Miodoński and Bär (1985, 1987a, 1987b, 1989).…”

“…Its development, anatomy, morphology, physiology, and regeneration are well-studied (Hua et al,2013;Kha et al, 2019;Walls, 1942). Studies on the ocular blood supply, and in particular on the microvascular anatomy, were done in two ranid species (Rana esculenta and Rana temporaria; Miodoński et al, 1985Miodoński et al, , 1987aMiodoński et al, , 1987bMiodoński et al, , 1989 and one urodelian species (Triturus cristatus carnifex; Lazzari et al, 1993). The authors convincingly demonstrated the detailed microvasculature of the choriocapillaries and the superficial hyaloid vascular system (Miodoński et al, 1985(Miodoński et al, , 1987a(Miodoński et al, , 1987b(Miodoński et al, , 1989 as well as the choroidal and iris angioarchitecture (Lazzari et al, 1993) by scanning electron microscopy of vascular corrosion casts.…”

Retinal vascularization in the grass goby,Zosterisessor ophiocephalus: a scanning electron-microscopic study of vascular corrosion casts

“…Vascular corrosion casts of the retinal vascularization have been obtained and observed with a scanning electron microscope. Up to now, this technique has been used to study the eye vascularization in amphibians (Miodonski & Bar 1987a, b, Lazari et al 1993, birds…”