. Quain's elements of anatomy . 42S THE EYE. superficial lens-fibres show indications of being composed of a number of regularsegments separated by sharply marked lines of inter-segmental substance. _ Epithelium of the capsule.—At the back of the lens the fibres aredirectly in contact with the inner siuface of the capsule, but in front theyare separated from the latter by a single layer of flattened, polygonal,nucleated cells, which covers the whole anterior surface underneath thecapsule. Towards the edge or equator of the lens the appearance andcharacter of these cells undergo a change : they
. Quain's elements of anatomy . 42S THE EYE. superficial lens-fibres show indications of being composed of a number of regularsegments separated by sharply marked lines of inter-segmental substance. _ Epithelium of the capsule.—At the back of the lens the fibres aredirectly in contact with the inner siuface of the capsule, but in front theyare separated from the latter by a single layer of flattened, polygonal,nucleated cells, which covers the whole anterior surface underneath thecapsule. Towards the edge or equator of the lens the appearance andcharacter of these cells undergo a change : they first gradually take on acolumnar form, and then, becoming more and more elongated, presentevery transition to the nucleated lens-fibres of the superficial layers, intowhich they are directly continuous. This transition is more easily tracedin the lens of some animals than in man (see fig. 367). Fig. Fig. 367.—Section through the margin of the rabbits lens, showing the TRANSITION OF THE EPITHELIUM INTO THE LENS-FIBRES (Babucllill). The capsule of the lens is a transparent, structureless membrane, somewhatbrittle and elastic in character, and when ruptured the edges roll outwards. The forepart of the capsule, from about ^^ inch from the chcumference, where the anteriorpart of the suspensory ligament joins it, is much thicker than the back : at theposterior pole of the lens the capsule is very thin indeed. In the adult it, likethe lens itself, is entirely non-vascular, but in the foetus there is a network ofvessels in the capsule, supplied by the terminal branch of the central arteryof the retina, which passes from the optic papilla through the canal of Stillingin the Adtreous humour to reach the back of the capsule, where it dividesinto radiating branches. After forming a fine network, these turn round themargin of the lens and extend forwards to become continuous with the vessel
Size: 3324px × 752px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1800, booksubjectanatomy, booksubjecthumananatomy
