Ciliary Body(redirected from Ciliary muscles)
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ciliary body[¦sil·ē‚er·ē ¦bäd·ē]
in terrestrial vertebrates, including humans, the part of the eye that converts blood serum into the intraocular fluid that is secreted into the posterior chamber of the eye. The ciliary body forms a circle of numerous radial folds (70 to 80 in humans) on the internal surface of the eye between the iris and the retina. It consists of mesodermal stroma and two neuroepithelia. The external pigmented neuroepithelium is a continuation of the pigmented epithelium of the retina, whereas the nonpigmented internal layer, which plays a major role in the secretion of intraocular fluid, is a continuation of the retina proper.
Fibers of the zonule of Zinn are attached to the basal membrane of the ciliary folds. The amount of tension of the ligament is determined by contraction of the circular ciliary muscle situated in the stroma of the ciliary body near the place of contact with the sclera. The tension of the ciliary muscle determines the shape of the crystalline lens. The ciliary body is the most vascularized part of the eye; it is supplied by blood vessels from the systemic circulation of the iris.
Inflammation of the ciliary body is called cyclitis; inflammation of both the ciliary body and the iris is called iridocyclitis.
REFERENCESStroeva, O. G. Morfogenez i vrozhdennye anomalii glaza mlekopitaiushchikh. Moscow, 1971.
Davson, H. The Physiology of the Eye, 3rd ed. Edinburgh-London, 1972.
O. G. STROEVA