Microvasculature of the rat eye: scanning electron microscopy of vascular corrosion casts.
Methylmethacrylate castings of the eye microvasculature were prepared from 10 Spargue-Dawley rats and studied by electron microscopy. The choroidal arterioles are larger in diameter than retinal arterioles, and have a shorter course to choroidal capillaries than retinal arterioles to retinal capillaries. Retinal capillaries are extremely thin in diameter and form a sparse retinal capillary network. The choriocapillaris is large and sinusoid-like, forming a compactly arranged network in the choroid. These differences in the microvasculature between the choroid and retina help explain the differences in ocular hemodynamics; that is, the blood flow in the choroid is faster than that in the retina. Capillaries of the iris show a zigzag configuration, which may be an accommodation for dilation and constriction of the pupil. Capillaries of the ciliary body are of large diameter forming leaf-like configurations, presumably to contribute to the secretion of the aqueous humor. Capillaries of the conjunctiva exhibit a somewhat coiled configuration, the arrangement of which reduce tension of the conjunctiva vessels caused by eyeball movement. Intra-arterial cushions, which control blood flow at the branching sites, are found in both choroidal or retinal arterioles.
Ninomiya
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H
Department of Laboratory Animal Science, Azabu University, 1-17-71 Fuchinobe Sagamihara, 229-8501 Japan. fwgc0555@mb.infoweb.ne.jp
Kuno
H
H
D000818:Animals; D002924:Ciliary Body / Q000648:ultrastructure; D003228:Conjunctiva / Q000648:ultrastructure; D016319:Corrosion Casting / Q000662:veterinary; D004195:Disease Models, Animal; D005123:Eye / Q000098:blood supply* / Q000648:ultrastructure*; D005260:Female; D007498:Iris / Q000648:ultrastructure; D008833:Microcirculation / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning / Q000662:veterinary; D051381:Rats; D017207:Rats, Sprague-Dawley / Q000033:anatomy & histology*; D012171:Retinal Vessels / Q000648:ultrastructure