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Stroma of iris

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Connective and vascular tissue of the iris
Stroma of iris
The upper half of a sagittal section through the front of the eyeball. ("Stroma of iris" labeled at bottom right.)
Details
Identifiers
Latinstroma iridis
TA98A15.2.03.031
FMA58526
Anatomical terminology[edit on Wikidata]

The stroma of the iris is a fibrovascular layer of tissue located at the front of the iris.

Structure

The stroma is a delicate interlacement of fibres. Some circle the circumference of the iris and the majority radiate toward the pupil. Blood vessels and nerves intersperse this mesh.

In dark eyes, the stroma often contains pigment granules. Blue eyes and the eyes of albinos, however, lack pigment.

Structure of the iris and surrounding parts showing the stroma of iris (stroma iridis).

The stroma connects to a sphincter muscle (sphincter pupillae), which contracts the pupil in a circular motion, and a set of dilator muscles (dilator pupillae) which pull the iris radially to enlarge the pupil, pulling it in folds. The back surface is covered by a commonly, heavily pigmented epithelial layer that is two cells thick (the iris pigment epithelium), but the front surface has no epithelium. This anterior surface projects as the muscles dilate.

References

External links

Anatomy of the globe of the human eye
Fibrous tunic
(outer)
Sclera
Cornea
1:posterior segment 2:ora serrata 3:ciliary muscle 4:ciliary zonules 5:Schlemm's canal 6:pupil 7:anterior chamber 8:cornea 9:iris 10:lens cortex 11:lens nucleus 12:ciliary process 13:conjunctiva 14:inferior oblique muscule 15:inferior rectus muscule 16:medial rectus muscle 17:retinal arteries and veins 18:optic disc 19:dura mater 20:central retinal artery 21:central retinal vein 22:optic nerve 23:vorticose vein 24:bulbar sheath 25:macula 26:fovea 27:sclera 28:choroid 29:superior rectus muscle 30:retina1: posterior segment2: ora serrata3: ciliary muscle4: ciliary zonules5: Schlemm's canal6: pupil7: anterior chamber8: cornea9: iris10: lens cortex11: lens nucleus12: ciliary process13: conjunctiva14: inferior oblique muscule15: inferior rectus muscule16: medial rectus muscle17: retinal arteries and veins18: optic disc19: dura mater20: central retinal artery21: central retinal vein22: optic nerve23: vorticose vein24: bulbar sheath25: macula26: fovea27: sclera28: choroid29: superior rectus muscle30: retina
1:posterior segment 2:ora serrata 3:ciliary muscle 4:ciliary zonules 5:Schlemm's canal 6:pupil 7:anterior chamber 8:cornea 9:iris 10:lens cortex 11:lens nucleus 12:ciliary process 13:conjunctiva 14:inferior oblique muscule 15:inferior rectus muscule 16:medial rectus muscle 17:retinal arteries and veins 18:optic disc 19:dura mater 20:central retinal artery 21:central retinal vein 22:optic nerve 23:vorticose vein 24:bulbar sheath 25:macula 26:fovea 27:sclera 28:choroid 29:superior rectus muscle 30:retina
Uvea / vascular
tunic (middle)
Choroid
Ciliary body
Iris
Retina (inner)
Layers
Cells
Other
Anatomical regions
of the eye
Anterior segment
Posterior segment
Other
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