Eye
General
Anatomy & histology-ciliary body
Author: Nat Pernick, M.D.
Last author update: 1 February 2014
Last staff update: 29 June 2020
Copyright: 2004-2024, PathologyOutlines.com, Inc.
PubMed Search: Ciliary body[title] eye review[ptyp]
Cite this page: Pernick N. Anatomy & histology-ciliary body. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/eyeuveaciliarybodygeneral.html. Accessed April 19th, 2024.
Definition / general
- Middle segment of uveal tract, between iris and choroid
- Composed of pars plicata and pars plana
- Holds lens in place
- Cyclectomy: resecting portion of ciliary body containing tumor; may also include other surrounding structures
- Pars plicata: 70 sagitally oriented folds or ciliary processes that gradually merge with posterior flat pars plana, which merges posteriorly with serrated, anterior border of retina (ora serrata)
- Ciliary epithelium composed of inner epithelial layer (nonpigmented, contiguous with aqueous of posterior chamber) and outer epithelial layer (pigmented, unites with retinal pigment epithelium at ora serrata)
- Outer epithelial layer overlies PAS+ basal lamina that thickens in diabetes mellitus
- Zonules: acellular fibers that attach crests of nonpigmented ciliary epithelium in pars plicata to capsule of crystalline lens
- Ciliary body has 3 distinct bundles of smooth muscle which assist in accommodation; as muscle contacts, ciliary body extends forward, reducing pressure on zonules, enabling lens to become less concave, thereby increasing its refractive power
Microscopic (histologic) images
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Ciliary body, iris and lens
Ciliary process zonule fibers
