Contents >> what is Iris? structure of Iris, nerve supply of Iris.
Today I am telling you about Iris which is an important part of our eye.so we should know about it please read the article fully learn about the Iris, structure of Iris, Nerve supply of Iris.
Location of Iris
The iris lies in front of the lens and the ciliary body.It separates the anterior chamber from the posterior chamber.Pupil is situated slightly nasal side of center.Its periphery or root is attached to anterior end of the ciliary body.Anterior surface of the iris is divided into two zones- 1.central pupilary zone 2.peripheral ciliary zone.There junction is a circular ridge,called "collarette" which marks the embryonic site of the minor vascular circle of iris, from which the embryonic pupillary membrane originated.the ciliary zone is marked by many ridges and crypts,but the pupillary zone is relatively flat.
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Structure of Iris
Today I am telling you about Iris which is an important part of our eye.so we should know about it please read the article fully learn about the Iris, structure of Iris, Nerve supply of Iris.
Location of Iris
The iris lies in front of the lens and the ciliary body.It separates the anterior chamber from the posterior chamber.Pupil is situated slightly nasal side of center.Its periphery or root is attached to anterior end of the ciliary body.Anterior surface of the iris is divided into two zones- 1.central pupilary zone 2.peripheral ciliary zone.There junction is a circular ridge,called "collarette" which marks the embryonic site of the minor vascular circle of iris, from which the embryonic pupillary membrane originated.the ciliary zone is marked by many ridges and crypts,but the pupillary zone is relatively flat.
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Structure of Iris
- Anterior endothelium is continuous with the corneal endothelium.
- Stroma consists of spongy connective tissue with nerves, smooth muscles, and radial blood vessels forming the minor circle of iris.
- Smooth muscles are two in number
- Sphincter pupullae : A circular bundle of smooth muscles running around the pupillary margin, causes constriction of the pupil.
- Dilator pupillae : Arranged radially near the root of the iris-causes dilatation of the pupil.
- Posterior two-layered epithelium : Both layers are pingmented and developmentally derived from the retina .The anterior layer consists of flattened cells and the posterior layer consists of cuboidal
- Sensory : Naso ciliary nerve, branch of 1st division of 5th cranial.
- Sphincter pupillae: Oculomotor nerve (3rd cranial)
- Dilator pupillae : Nerves derived from cervical sympathetic chain.
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