Читать книгу Essentials of Veterinary Ophthalmology - Kirk N. Gelatt - Страница 56

The lens is circumferentially suspended from the ciliary body by fibers called zonules. Zonular attachment is achieved by a complex arrangement of fibers that insert onto the lens capsule in a zone encompassing the equator and a short distance both anterior and posterior to the equator (Figure 1.50a and b). Each zonular fiber is made of numerous small fibrils, which are visible under SEM as they attach to the lens capsule. The zonular fibers spread out near the equator and terminate into smaller bundles. Each of these bundles also fans out and forms a network that ramifies over the surface of the lens capsule, approximately 1.5–2.0 mm away from the lens equator.

Figure 1.50 Zonular attachments to the lens in a dog. (a) SEM shows that zonules (Z) extend from the ciliary body onto the equator of the lens (L) in a ringlike manner, covering each ciliary process. (Original magnification, 30×.) (b) SEM shows that each zonule consists of bundles (arrows) of fibrils, which are most apparent next to the lens (L). (Original magnification, 78×.) (c) SEM shows termination of zonular fibrils, which unravel to form a dense meshwork over the capsule that greatly increases the surface area of attachment. A, zonular fiber. (Original magnification, 1600×.)