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Topic: Choroid


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In the News (Sat 17 Aug 19)

  
  Choroid Plexus Cyst
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].
www.obfocus.com /high-risk/birthdefects/choroidplexus.htm   (462 words)

  
 Ophthalm-AUS - Oben's Ophthalmology Site
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.
home.iprimus.com.au /oben/choroid.htm   (786 words)

  
 Ocular Pathology Study Guide: CHOROID
The choroid is that part of the uveal tract extending from the edge of the optic nerve head to the ora serrata.
The usually heavily pigmented posterior or choroidal portion of the uveal tract is loosely adherent to the overlying sclera.
The enlargement is limited posteriorly by attachment of the choroid to the sclera, augmented by the outward passage of the vortex veins, by the perforating short posterior ciliary arteries and by border tissue at the scleral aperture for the optic nerve.
www.medrounds.org /ocular-pathology-study-guide/2005/10/choroid.html   (522 words)

  
 eMedicine - Choroid Plexus Papilloma : Article by Cheryl Ann Palmer, MD   (Site not responding. Last check: 2007-10-18)
Choroid plexus papillomas (CPPs) are benign neoplasms of the choroid plexus, a structure made from tufts of villi within the ventricular system that produces cerebrospinal fluid (CSF).
The choroid plexus is associated with the ventricular lining of the body, trigone, and inferior horn of the lateral ventricles; the foramen of Monro; the roof of the third ventricle; and the posterior portion of the roof of the fourth ventricle.
Choroid plexus carcinomas (see Image 3) are characterized by anaplastic features such as nuclear pleomorphism and hyperchromasia, increased mitotic activity, the occurrence of tumor giant cells, tumor necrosis, and frank invasion of the underlying brain parenchyma.
www.emedicine.com /med/topic2992.htm   (3226 words)

  
 AmnioNet : Brain Development I// Choroid Plexus Cysts
The choroid glomi are paired structures that produce cerebro-spinal fluid, which is a sugar rich material that bathes the brain and spinal cord, nourishing and supporting nerve cell growth.
Both choroid glomi ('glomus' is singular, 'plexus' is an equivalent term) are the first structures to be identified ultrasonically within the head, being visible 5 to 6 weeks after conception.
Fluid exudes from the surface of the choroid.
www.amnionet.com /p67.htm   (291 words)

  
 Choroid Plexus Papillomas
Choroid plexus papillomas are benign neoplastic growths that arise from the ventricular choroid plexus and can be considered of ependymal origin.
Typical of the choroid plexus papilloma in microscopic examination is its resemblance to the normal choroid plexus.
Ventricular enlargement is seen in association with most but not all choroid plexus papillomas This may be due to a combination of factors: overproduction of CSE, obstruction of CSF pathways by the tumor mass, or subarachnoid scarring due to recurrent bleeding from the tumor.
www.angelfire.com /wa/wafshaf50/cpp.html   (578 words)

  
 Choroid Plexus Cysts   (Site not responding. Last check: 2007-10-18)
The choroid plexus is the tissue within the brain, which produces the cerebrospinal fluid.
Children with choroid plexus cysts are developmentally normal and indistinguishable from those in whom no cysts were seen on ultrasound examination during pregnancy.
If a fetus with choroid plexus cysts has a detailed ultrasound, including views of the heart and of hands that open and close, and shows no other abnormalities, then the risk of Trisomy 18 is only 1 in about 250.
www.wcox.com.au /choroid.htm   (457 words)

  
 Choroid Plexus Tumor - My Child Has - Children's Hospital Boston
Choroid plexus tumors are rare, representing only 3 percent of pediatric brain tumors, but account for 10-20 percent of pediatric brain tumors that occur within the first year of life.
Diagnostic procedures for a choroid plexus tumor, like other brain tumors, are necessary to determine the exact type of tumor and whether the tumor has spread.
Choroid plexus papillomas are usually cured by surgical removal of the tumor.
www.childrenshospital.org /az/Site2138/mainpageS2138P0.html   (1230 words)

  
 Choroid Plexus Tumors Information on Healthline
Choroid plexus tumors (CPTs) are rare abnormal growths on a part of the brain called the choroid plexus.
The choroid plexus is the structure in the brain that produces the cerebrospinal fluid that coats the brain and spinal cord.
A CPP is a benign, slow-growing, wart-like tumor that tends to grow on the surface of the choroid plexus.
www.healthline.com /galecontent/choroid-plexus-tumors   (724 words)

  
 The Choroid and Sclera   (Site not responding. Last check: 2007-10-18)
The inner layer, immediately surrounding the pigment layer of the retina, is the choroid, which is a highly vascularized pigmented layer.
Blood vessels first appear in the choroid during the 15th week of development, and arteries and veins can be recognized by the 22nd week.
At the posterior end of the optic cup, the choroid forms a sheath around the optic nerve.
www.vision.ca /eye/choroid_sclera.html   (161 words)

  
 Neuroembryology: Choroid Plexus
In the adult, cerebrospinal fluid (CSF) is formed by choroid plexus in the 1) body and inferior horns of the lateral ventricles, 2) roof of the 3rd ventricle of the diencephalon, and 3) roof of the 4th ventricle in the medulla.
Apertures in the 4th ventricle (foramina of Magendi and Luschka), which develop during the 3rd month, permit the flow of CSF from within the ventricles to subarachnoid spaces surrounding the brain and spinal cord.
The choroid fissure and its associated choroid plexus is at first on the thinned medial wall on the dorsal aspect of the developing hemisphere.
isc.temple.edu /neuroanatomy/lab/embryo_new/choroid   (180 words)

  
 Choroid Plexus Tumors - MEDSTUDENTS - Neurosurgery
The normal choroid plexus is not calcified in adults, especially in the lateral ventricle.
The blood supply from choroidal vessels is posteroinferior to the bulk of the tumor and therefore hidden from the direct view of the surgeon in this approach.
Choroid Plexus Papilloma and Carcinomas, in Youmans : Neurological Surgery.
www.medstudents.com.br /neuroc/neuroc5.htm   (1705 words)

  
 Choroid - Wikipedia, the free encyclopedia
The choroid, also known as the choroidea or choroid coat, is the vascular layer of the eye lying between the retina and the sclera.
Along with the ciliary body and iris, the choroid forms the uveal tract.
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.
en.wikipedia.org /wiki/Choroid   (275 words)

  
 Ask an Expert: Choroid plexus cysts
A choroid plexus cyst is a fluid-filled structure surrounded by normal tissue in the choroid plexus of the lateral cerebral ventricle - this is an area of the brain.
Choroid plexus cysts can be seen on ultrasound in the fetal brain during the end of the first trimester and into the second trimester of pregnancy - this can be normal.
Thus, when choroid plexus cysts are seen during pregnancy on ultrasound, it does not automatically mean the baby will be stillborn or definitely have trisomy 18 or other abnormalities.
www.netwellness.org /question.cfm/23169.htm   (419 words)

  
 uhrad.com - Body Imaging Files
Choroid plexus appears in 6th week gestation, initially in the roof of the 4th ventricle, then in the lateral ventricles, and finally in the 3rd ventricle.
Subsequently, growth of the choroid relative to that of the ventricles slows, until the choroid plexus has assumed its adult appearance by the 20th week of gestation.
Choroid Plexus Cysts are believed to derive from folding of the neuroepithelium with subsequent accumulation of CSF and debris.
www.uhrad.com /ctarc/ct019.htm   (699 words)

  
 MERSI Ocular Immunology and Uveitis Foundation| Patient Information | Glossary
The choroid is a soft, thin, brown, extremely vascular layer, lining the inner surface of the sclera.
The principal function of the choroid lies in the blood nourishment of the outer layers of the retina.
Inflammation of the choroid, the middle layer of the eye composed of blood vessels that nourish the back of the eye.
www.uveitis.org /patient/glossary/a_f.html   (4315 words)

  
 Transepithelial Transport of Organic Anions across the Choroid Plexus: Possible Involvement of Organic Anion ...
The lysate of the isolated choroid plexus was prepared by sonicating the tissue in artificial CSF.
The lysate of isolated choroid plexus and lung (6.25 and 12.5 µg of protein, respectively) was subjected to Western blot analysis to determine the expression level of MRP1.
G in the choroid plexus were studied in vivo and in vitro.
jpet.aspetjournals.org /cgi/content/full/290/1/289   (4432 words)

  
 Choroid Plexus
The choroid plexus is found on the walls or roof of each of the four ventricles.
CSF is formed by the choroid plexuses which are vascular structures that project into the brain ventricles.
Part of the choroid plexus is near the pineal gland whose secretions may become calcified.
www3.umdnj.edu /histsweb/lab9/lab9choroidplexus.html   (265 words)

  
 Blood Brain Barrier CSF Anatomy and Physiology   (Site not responding. Last check: 2007-10-18)
The preponderance of choroid plexus is distributed throughout the fourth ventricle near the base of the brain and in the lateral ventricles inside the right and left cerebral hemispheres.
The cells of the choroidal epithelium are modified and have epithelial characteristics.
While the capillaries of the choroid plexus are fenestrated, non-continuous and have gaps between the capillary endothelial cells allowing the free-movement of small molecules, the adjacent choroidal epithelial cells form tight junctions preventing most macromolecules from effectively passing into the CSF from the blood (Brightman, 1968).
users.ahsc.arizona.edu /davis/csfanatomy.htm   (407 words)

  
 Obstetrical sonography: the best way to terrify a pregnant woman. J Ultrasound Med 2000; 19:1-5 Filly RA.
The choroid plexus cyst occurs in 1-2% of fetuses (3), echogenic bowel occurs in approximately 1% of all second-trimester fetuses (44) (many more if high frequency transducers are employed) and mild pyelectasis in 3% of normal fetuses (54).
Clark SL, DeVore GR, Sabey PL. Prenatal diagnosis of cysts of the fetal choroid plexus.
Choroid plexus cysts and trisomy 18: risk modification based on maternal age and multiple-marker screening.
www.choroidplexuscyst.org /filly.html   (3354 words)

  
 Monash Ultrasound for Women - Choroid Plexus Cysts - Melbourne Australia
The chambers in the centre of each hemisphere are lined with by a thick layer of material called the choroid.
The choroid produces the fluid, which circulates throughout the chamber system.
Choroid plexus cysts are a variation of normal and seen in approximately 1-3% of normal pregnancies.
www.monashultrasound.com.au /library/factsheets_cpc.html   (710 words)

  
 Choroid Plexus Tumor   (Site not responding. Last check: 2007-10-18)
The choroid plexus papilloma is a rare, benign tumor most common in children under the age of 2.
The choroid plexus carcinoma is the malignant form of this tumor.
The prognosis for choroid plexus papilloma is excellent following a complete resection of their tumor.  No further treatment is required and long-term survival is near 100 percent.
www.stjude.org /disease-summaries/0,2557,449_2160_7268,00.html   (524 words)

  
 Dark Choroid: A Sign of Stargardt’s Disease
The areas of flecks hyperfluoresced in an irregular fashion early in the study, and faded slightly in the later images.
Because of the excessive storage of lipofuscin in the RPE, the choroidal fluorescence is blocked, producing a dark background with a high-contrast image.
From a photographic standpoint, this case produced excellent images due to the dark background, producing dramatic images of the retinal vasculature which is shown clearly against this dark background.
www.brysontaylor.com /jop499.HTM   (504 words)

  
 Lab exercises- Retina, choroid, and sclera
Above the sclera are the layers of the darkly staining choroid (note the large vessels in the vessel layer.
The next two views show the sclera and choroid in relationship to the retina (next photograph).
There is some controversy about whether it belongs to the retina or the choroid (see your text).
cellbio.utmb.edu /microanatomy/eye/Retina_lab.htm   (745 words)

  
 The choroid plexus prevents build up of plaque related to Alzheimer's disease
Researchers have discovered that an organ in the brain called the choroid plexus apparently plays a critical role in preventing the accumulation of a protein associated with Alzheimer's disease.
The researchers found that the choroid plexus acts as a sort of "fishnet" that captures the protein, called beta-amyloid, and prevents it from building up in the cerebrospinal fluid, which surrounds and bathes the brain and spinal cord.
Studies using rat brains indicated that choroidal cells removed about five times more beta-amyloid from cerebrospinal fluid compared to how much of the protein the cells allowed to pass into the fluid.
www.news-medical.net /?id=16856   (801 words)

  
 Functional Evidence for Presence of PEPT2 in Rat Choroid Plexus: Studies with Glycylsarcosine -- Teuscher et al. 294 ...
The pH dependence of GlySar is evident by a sharp decrease in uptake as the extracellular pH rises from 6.5 to 8.0.
choroid plexus may be comparable to that found in the kidney.
Huang JT (1982) Accumulation of peptide Tyr-D-Ala-Gly by choroid plexus during ventriculocisternal perfusion of rat brain.
jpet.aspetjournals.org /cgi/content/full/294/2/494   (3674 words)

  
 Choroid Plexus Papilloma
Choroid plexus papillomas grow slowly until they eventually block the flow of cerebrospinal fluid causing hydrocephalus and increased pressure inside the skull.
A neurological evaluation should be done if a patient has slowly increasing signs of mental dysfunction, new seizures, persistent headaches or evidence that there is pressure inside the skull such as vomiting or swelling or protrusion of the blind spot at the back of the eye.
Choroid plexus carcinoma is a rare, malignant form of this tumor.
www.cedars-sinai.edu /5311.html   (324 words)

  
 FOURTH VENTRICLE CHOROID PLEXUS PAPILLOMA PRESENTING ONLY WITH RHINORRHEA
Choroid plexus papilloma mass was enhancing diffusely, skull base was not involved (C).
Hydrocephalus is a frequent and an important consequence of choroid plexus tumors.
Abbott KH, Rollas ZH, Meagher JN: Choroid plexus papilloma causing spontaneous subarachnoid hemorrhage.
www.med.ege.edu.tr /~norolbil/1999/NBD01499.html   (1493 words)

  
 Medical Dictionary: Choroid plexus - WrongDiagnosis.com
Choroid plexus: a vascular plexus of the cerebral ventricles that regulate intraventricular pressure
Choroid plexus : secretory epithelium and associated blood vessels of the lateral, third, and fourth ventricles, which regulates production and composition of cerebrospinal fluid.
Choroid plexus : A villous structure of tangled masses of BLOOD VESSELS contained within the third, lateral, and fourth ventricles of the BRAIN.
www.wrongdiagnosis.com /medical/choroid_plexus.htm   (260 words)

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