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Encyclopedia > Choroid
Choroid
Schematic cross section of the human eye; choroid is shown in yellow.
Interior of anterior half of bulb of eye. (Choroid labeled at right, second from the bottom.)
Latin choroidea
Gray's subject #225 1009
MeSH Choroid
Dorlands/Elsevier c_32/12237606

The choroid, also known as the choroidea or choroid coat, is the vascular layer of the eye lying between the retina and the sclera. The choroid provides oxygen and nourishment to the outer layers of the retina [1]. Image File history File links Schematic_diagram_of_the_human_eye_with_English_annotations. ... Image File history File links Gray875. ... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... Elseviers logo Elsevier, the worlds largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. ... Vascular is an adjective for the word vessel and refers to tube-like structures. ... The human eye. ... Human eye cross-sectional view. ... Schematic diagram of the human eye. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ...


Along with the ciliary body and iris, the choroid forms the uveal tract. In humans and other primates, darkly colored melanin pigment in the choroid helps limit reflections within the eye that would potentially result in the perception of confusing images. Poor vision frequently results from lack of this pigmentation in human albinos. By contrast, the choroid of many other animals contains reflective materials that help to collect light in dim situations; this is one type of tapetum lucidum. Schematic diagram of the human eye The ciliary body is the part of the eye containing the ciliary muscle and ciliary processes. ... The human iris The iris is the green/grey/brown area. ... For the Pacific island, see Wallis Island. ... For the ecclesiastical use of this term, see primate (religion) Families 13, See classification A primate is any member of the biological order Primates, the group that contains all lemurs, monkeys, and apes, including humans. ... Broadly, melanin is any of the polyacetylene, polyaniline, and polypyrrole blacks and browns or their mixed copolymers. ... For animal and plant pigments, see Pigment, biology. ... Albinism is a genetic condition resulting in a lack of pigmentation in the eyes, skin and hair. ... tapetum lucidum in a calf eye, with the retina hanging down The tapetum lucidum (Latin: bright carpet) is a reflecting layer immediately behind, and sometimes within, the retina of the eye of many vertebrates (though not humans); it serves to reflect light back to the retina, increasing the quantity of...


The red eye effect on photos is caused by the reflection of light from choroid. It appears red because of the choroid's blood vessels.


Layers

The structure of the choroid is generally divided into four layers:

  • Haller's layer - outermost layer of the choroid consisting of larger diameter blood vessels
  • Sattler's layer - layer of medium diameter blood vessels
  • Choriocapillaris - layer of capillaries
  • Bruch's membrane - innermost layer of the choroid

Sattlers layer is layer of medium diameter blood vessels of the choroid. ... The choriocapillaris is a layer of capillaries that is immediately adjacent to Bruchs membrane in the choroid. ... Bruchs membrane is the innermost layer of the choroid. ...

See also

Sensory system - Visual system - Eye - edit
Fibrous tunic: Conjunctiva | Sclera | Cornea | Schlemm's canal | Trabecular meshwork 

Uvea: Choroid | Iris | Pupil | Ciliary body  In medicine, Chorioretinitis is an inflammation of the choroid and retina of the eye. ... Uveitis specifically refers to inflammation of the middle layer of the eye, termed the uvea but in common usage may refer to any inflammatory process involving the interior of the eye. ... This article or section may be confusing for some readers, and should be edited to be clearer or more simplified. ... The visual system is the part of the nervous system which allows organisms to see. ... The human eye. ... The sclera and cornea form the fibrous tunic of the bulb of the eye; the sclera is opaque, and constitutes the posterior five-sixths of the tunic; the cornea is transparent, and forms the anterior sixth. ... The conjunctiva is a membrane that covers the sclera (white part of the eye) and lines the inside of the eyelids. ... Schematic diagram of the human eye. ... The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber, providing most of an eyes optical power [1]. Together with the lens, the cornea refracts light and, as a result, helps the eye to focus. ... Schlemms canal, also known as canal of Schlemm, is a circular channel in the eye that collects aqueous humor from the anterior chamber and delivers it into the bloodstream . ... This is an area of tissue located around the base of the cornea, near the ciliary body, and is responsible for draining the aqueous humour from the eye via the anterior chamber (the chamber on the front of the eye covered by the cornea). ... For the Pacific island, see Wallis Island. ... The human iris The iris is the green/grey/brown area. ... The human eye The pupil is the central transparent area (showing as black). ... Schematic diagram of the human eye The ciliary body is the part of the eye containing the ciliary muscle and ciliary processes. ...


Retina : Macula | Fovea | Optic disc  Human eye cross-sectional view. ... Human eye cross-sectional view. ... The fovea, a part of the eye, is a spot located in the center of the macula. ... The optic disc or optic nerve head is the point in the eye where the optic nerve fibres leave the retina; it is not sensitive to light and thus also known as the blind spot or anatomical blind spot. Inspection of the optic disc by ophthalmoscopy can give an indication...


Anterior segment (Anterior chamber, Aqueous humour, Posterior chamber, Lens) | Posterior segment (Vitreous humour) anterior segment ... The anterior chamber if the fluid-filled space inside the eye between the iris and the corneas innermost surface, the endothelium . ... The aqueous humour is the clear, watery fluid that fills the complex space in the front of the eye which is bounded at the front by the cornea and at the rear by the front surface or face of the vitreous humour. ... The posterior chamber is a narrow chink behind the peripheral part of the iris, and in front of the suspensory ligament of the lens and the ciliary processes. ... Light from a single point of a distant object and light from a single point of a near object being brought to a focus by changing the curvature of the lens. ... The posterior segment is the back two-thirds of the eye that includes the anterior hyaloid membrane and all structures behind it: the vitreous humor, retina, choroid, and optic nerve. ... Vitreous humour is the clear aqueous solution that fills the space between the lens and the retina of the vertebrate eyeball. ...

Sensory system - Visual system - edit
Eye | Optic nerve | Optic chiasm | Optic tract | Lateral geniculate nucleus | Optic radiation | Visual cortex

  Results from FactBites:
 
Choroid Plexus Cyst (462 words)
The choroid plexuses are structures in the ventricles (spaces) of the brain that produce the cerebrospinal fluid.
Choroid plexus cysts are seen during 1% to 3% of all mid-trimester prenatal ultrasound examinations [1].
Choroid plexus cysts are believed to be caused by abnormal folding of the epithelium lining of the choroid plexus which traps fluid and debris [2,3].
Ophthalm-AUS - Oben's Ophthalmology Site (786 words)
Choroid is the vascular coat of the eye, forming part of the uveal tract consisting of the iris,ciliary body & choroid.
Most of the vessels of the outer choroid, except near the disc and under the macula are veins.
Choroidal veins drain into ampullae, which are dilated segments of the vortices lying within the scleral canals.
  More results at FactBites »


 

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