Editing Ciliary body (section)

==Structure==
The ciliary body is a ring-shaped thickening of tissue inside the [[eye]] that divides the [[Posterior chamber of eyeball|posterior chamber]] from the [[vitreous body]].  It contains the [[ciliary muscle]], vessels, and fibrous connective tissue.  Folds on the inner ciliary epithelium are called [[ciliary processes]], and these secrete aqueous humor into the posterior chamber. The aqueous humor then flows through the iris into the anterior chamber.<ref>Lang, G. ''Ophthalmology: A Pocket Textbook Atlas, 2 ed.''. Pg. 207. Ulm, Germany. 2007.</ref>

The ciliary body is attached to the lens by [[connective tissue]] called the [[Zonule of Zinn]] (fibers of Zinn). Relaxation of the ciliary muscle puts tension on these fibers and changes the shape of the lens in order to [[Focus (optics)|focus]] [[light]] on the retina.

The inner layer is transparent and covers the [[vitreous body]], and is continuous from the neural tissue of the [[retina]]. The outer layer is highly pigmented, continuous with the [[retinal pigment epithelium]], and constitutes the cells of the [[iris dilator muscle|dilator muscle]]. This double membrane is often considered continuous with the retina and a rudiment of the embryological correspondent to the retina. The inner layer is unpigmented until it reaches the [[iris (anatomy)|iris]], where it takes on pigment. The retina ends at the [[ora serrata]].

The space between the ciliary body and the base of the iris is the ciliary [[Sulcus (morphology)|sulcus]].<ref>Schnaudigel OE. Anatomie des Sulcus ciliaris [Anatomy of the ciliary sulcus]. Fortschr Ophthalmol. 1990;87(4):388-9. German. PMID 2210569.</ref> 

===Nerve supply===
[[File:Ciliary ganglion pathways.png|thumb|right|380px|Ciliary [[ganglion]] with parasympathetic fibers of ciliary nerves.]]
The parasympathetic innervation of the ciliary body is the most clearly understood.  Presynaptic parasympathetic signals that originate in the [[Edinger-Westphal nucleus]] are carried by cranial nerve III (the [[oculomotor nerve]]) and travel through the [[ciliary ganglion]].  Postsynaptic fibers from the ciliary ganglion form the short ciliary nerves.  [[Parasympathetic]] activation of the M3 [[muscarinic receptors]] causes ciliary muscle contraction, the effect of contraction is to decrease the diameter of the ring of ciliary muscle.<ref>{{cite book | vauthors = Moore KL, Dalley AF | title = Clinically Oriented Anatomy | chapter = Head (chapter 7) | page = [https://archive.org/details/clinicallyorient00moor_1/page/972 972] | publisher = Lippincott Williams & Wilkins | year = 2006 | edition = 5th | isbn = 0-7817-3639-0 | chapter-url-access = registration | chapter-url = https://archive.org/details/clinicallyorient00moor_1/page/972 }}</ref> The parasympathetic tone is dominant when a higher degree of accommodation of the lens is required, such as reading a book.<ref>{{cite book |first1=Ryan E. |last1=Hibbs |first2=Alexander C. |last2=Zambon |chapter=Agents Acting at the Neuromuscular Junction and Autonomic Ganglia |chapter-url=http://accesspharmacy.mhmedical.com/content.aspx?bookid=374&sectionid=41266217&jumpsectionID=41268392 |editor1-first=Laurence L. |editor1-last=Brunton |editor2-first=Bruce A. |editor2-last=Chabner |editor3-first=Björn C. |editor3-last=Knollmann |title=Goodman & Gilman's The Pharmacological Basis of Therapeutics |publisher=McGraw-Hill |year=2011 |edition=12th |isbn=978-0-07-162442-8 |title-link=Goodman & Gilman's The Pharmacological Basis of Therapeutics |access-date=2015-05-22 |archive-date=2016-03-03 |archive-url=https://web.archive.org/web/20160303220848/http://accesspharmacy.mhmedical.com/content.aspx?bookid=374&sectionid=41266217&jumpsectionID=41268392 |url-status=dead }}</ref>

The ciliary body is also known to receive sympathetic innervation via long ciliary nerves.<ref>{{cite journal |pmid=4198985 |year=1973 |last1=Ruskell |first1=G. L. |title=Sympathetic innervation of the ciliary muscle in monkeys |journal=Experimental Eye Research |volume=16 |issue=3 |pages=183–90 |doi=10.1016/0014-4835(73)90212-1}}</ref>  When test subjects are startled, their eyes automatically adjust for distance vision.<ref name=pmid13823443>{{cite journal |doi=10.1016/0002-9394(59)90269-7 |pmid=13823443 |title=Autonomic Innervation of the Ciliary Body: A Modified Theory of Accommodation |journal=American Journal of Ophthalmology |volume=48 |issue=3 |pages=287–93 |year=1959 |last1=Fleming |first1=David G. |last2=Hall |first2=James L. }}</ref>