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CHAPTER 3 ▼ Uvea

FIGURĘ 3-12

Light micrograph of transverse section of the ciliary body, showing detachment from selera in region of supraciliaris. Ciliary muscie occupies most of ciliary body, stroma is located ^:n center of each process, zonular remnants are evident in posterior chamber between ciliary body and lens eguator.

The ciliary muscie is dually innervated by the autonomie nerrous system. Parasympathetic stimulation activates the muscie for contraction, whereas sym-pathetic innervation likely has an inhibitory effect that is a function of the level of parasympathetic actiyity.⁸'¹⁰

CS U ARY STROMA

The highly vascularized, loose connective tissue stroma of the ciliary body lies between the muscie and the epithelial layers and forms the core of each of the ciliary processes; it is continuous with the connective tissue that separates the bundles of ciliary muscie. Anteriorly, the stroma is continuous with iris stroma. It thins in the pars piana, where it continues posteriorly as choroidal stroma. The major arterial circle of the iris is located in the ciliary stroma anterior to the circular muscie and near the iris root. This circular artery is formed by the

FIGURĘ 3-13

Ciliary body, including the ciliary muscie and its components. Cornea and selera have been dissected away, but trabecular meshwork (a), SchlemnTs canal (b), and two external collectors (c), as well as ścierał spur (d), have been left undisturbed. Three components of ciliary muscie are shown separately, viewed from the outside and sectioned meridionally. Section 7 shows longitudinal ciliary muscie. In section 2, longitudinal ciliary muscie has been dissected away to show radial ciliary muscie. In section 3, only the innermost circular ciliary muscie is shown. Ciliary muscie originates in ciliary tendon, which includes ścierał spur (d) and adjacent connective tissue. The cel Is originate as paired V-shaped bundles. Longitudinal muscie forms long, V-shaped trellises (e) that terminate in epichoroidal stars (f). Arms of V-shaped bundles formed by radial muscie meet at wide angles (g) and terminate in ciliary processes. V-shaped bundles of circular muscie originate at such distant points in ciliary tendon that their arms meet at a very wide angle (h). Iridic portion is shown at (i), joining circular muscie ceils. (From Hogan Mj, Alvarado JA, Weddell JE: Histology of the human eye, Philadelphia, 1971, Saunders.)