Choroid


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choroid

[′kȯr‚ȯid]
(anatomy)
The highly vascular layer of the vertebrate eye, lying between the sclera and the retina.

Choroid

 

the connective-tissue coat of the eye located between the retina and the sciera. It is through the choroid that metabolites and oxygen pass from the blood to the pigmentary epithelium and photoreceptors of the retina.

The choroid includes a suprachoroid layer facing the sciera, a layer of large veins, a layer of arteries and veins, the choriocapil-laris, and Bruch’s membrane. The suprachoroid layer consists of compact reticulin and collagenous fibers. It is rich in fibroblasts and melanocytes, whose processes run through the entire choroid. The arteries and veins of the choroid have a double endothelial lining and basal and adventitial layers. Bruch’s membrane is made up of an amorphous substance containing elastic reticulin and collagenous fibers. It is bounded on the inside by a cell membrane of pigmentary epithelium and on the outside by a porous membrane of capillary endothelium.

The choroid of some fishes and mammals, for example, ungulates, has a reflecting layer, or a mirror, that intensifies the light stimulation of the photoreceptors and increases the sensitivity of the eye to light.

REFERENCES

Stebaeva, L. F., and O. V. Volkova. “Ul’trastruktura sosudistoi obo-lochki glaza krolika v norme i pri allergicheskom uveite.” Arkhiv anatomii, gistologii i embriologii, 1974, vol. 66, no. 2.
System of Ophthalmology, vol. 2. Edited by S. Duke-Elder. London, 1961.
Structure of the Eye: Proceedings of the Symposium at the Seventh International Congress of Anatomists. New York-London, 1961.

O. G. STROEVA

References in periodicals archive ?
Thus, cerebrospinal fluid circulates from blood in the choroid plexus to the ventricles, central canal and subarachnoid spaces, and then returns to the blood.
The choroid is implicated in the pathogenesis of several common ocular conditions, including age-related macular degeneration (AMD), central serous chorioretinopathy, and posterior uveitis.
In highly myopic eyes, the earliest changes begin in the choroid; thus, recent studies have focused on the choroid as an important structure involved in the pathophysiology of high myopia.
The avian eyeball is formed by the anterior segment (cornea, anterior chamber, iris, and lens) and the posterior segment (vitreous chamber, retina, pectin, choroid, and sclera).
List of False Positives and False Negatives on CT CT Diagnosis Histopathological Diagnosis Metastasis Grade III Astrocytoma Meningioma Oligoastrocytoma Cerebral abscess Grade III Astrocytoma GBM Tuberculosis Choroid plexus carcinoma Craniopharyngioma Choroid plexus carcinoma Glioblastoma multiforme Acute infarct Grade II glioma Table 7.
Carcinoid metastases in the choroid appear orange, as do thyroid metastases.
Surgical management of retinal detachments related to coloboma of the choroid.
The study also shows that signals secreted by the choroid plexus dynamically change during aging which affects aged stem cell behavior.
An interesting feature during this study was the constant immunolabelling of SVA within epithelial cells ol the choroid plexus of the brain and the surrounding endothelia of blood vessels in piglets with neurologic disease On the basis of the IHC results and molecular findings h different tissues of the brain, we theorized that the neurologic manifestations of SVA observed during this investigation might be due to early infection of the choroid plexus through alteration of the integrity of the vascular epithelium and subsequent dissemination to the adjacem neuropil.
Coloring of this part depends on degree of pigmentation in the choroid and also in Retinal pigment epithelium (RPE).
Wallman, "The multifunctional choroid," Progress in Retinal and Eye Research, vol.
Warf, at CURE Children's Hospital of Uganda, hypothesized that the addition of choroid plexus coagulation (CPC) at the time of the ETV, to reduce the rate of CSF production, might improve the outcome (22).