33407 SCAN0128

90 Clinical Anatomy of the Visua! System

FIGURĘ 5-5

Composite drawing of crystalline lens, cortex, epithelium, capsule, and zonular attachments.

A, Anterior central lens epithelium, seen in fiat section and cross section. Size and shape of these cells can be compared with those of cells in B, intermediate zonę, and C, the equatorial zonę. Mitosis occurs in the preequatorial zonę and at the equator, the cells are elongating (arrows) to form lens cortical cells. As they elongate, cells send processes anteriorly and posteriorly toward sutures, and their nuclei migrate somewhat anterior to equator to form lens bow. At the same time, nuclei become morę and morę displaced into lens as new cells are formed at equator. Lens capsule (d) is thicker anterior and posterior to equator than at equator itself. Anterior and equatorial capsule contains fine filamentous inclusions (double arrows); these are not present posteriorly. Lens fibers elongate into flattened hexagons (e) in cross section. Zonular fibers (f) attach to anterior and posterior capsule and to equatorial capsule, forming pericapsular or zonular lamella of lens (g). (From Hogan MJ, Alvarado JA, Weddell JE: Histology of the human eye, Philadelphia, 1971, Saunders.)