Anatomy & histology-ciliary body

Topic Completed: 1 February 2014

Minor changes: 29 June 2020

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PubMed Search: Ciliary body[title] eye review[ptyp]

Nat Pernick, M.D.
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Cite this page: Pernick N. Anatomy & histology-ciliary body. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/eyeuveaciliarybodygeneral.html. Accessed December 6th, 2021.
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

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Ciliary process zonule fibers

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