Capillary lamina of choroid
Capillary lamina of choroid | |
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Details | |
Identifiers | |
Latin | Lamina chorioidocapillaris |
TA98 | A15.2.03.006 |
FMA | 58437 |
Anatomical terminology [edit on Wikidata] |
The capillary lamina of choroid or choriocapillaris[1] is a part of the choroid of the eye.[2] It is a layer of capillaries immediately adjacent to Bruch's membrane of the choroid.[1] The choriocapillaris consists of a dense network of freely anastomosing highly permeable fenestrated large-calibre capillaries. It nourishes the outer avascular layers of the retina.[2]
Structure
Microstructure
In the capillaries that compose the choriocapillaris, the fenestrations are densest at the aspect of the capillaries that faces retina, whereas pericytes are situated at the obverse aspect.[3]
The choroidal blood vessels can be divided into two categories: the choriocapillaris, and the larger caliber arteries and veins that lie just posterior to the choriocapillaris (these can easily be seen in an albino fundus because there is minimal pigment obscuring the vessels).[4] The choriocapillaris forms a single layer of anastomosing, fenestrated capillaries having wide lumina with most of the fenestrations facing toward the retina. The lumen is approximately three to four times that of ordinary capillaries, such that two or three red blood cells can pass through the capillary abreast, whereas in ordinary capillaries the cells usually course single file. The cell membrane is reduced to a single layer at the fenestrations, facilitating the movement of material through the vessel walls. Occasional (pericyte)s (Rouget cells), which may have a contractile function, are found around the capillary wall. Pericytes have the ability to alter local blood flow. The choriocapillaris is densest in the macular area, where it is the sole blood supply for a small region of the retina. The choriocapillaris is unique to the choroid and does not continue into the ciliary body.[5]
Function
The choriocapillaris serves multiple functions that include sustaining the photoreceptors, filtering waste produced in the outer retina and regulating the temperature of macula.[6][7]
The capillary wall is permeable to plasma proteins which is probably of great importance for the supply of vitamin A to the pigment epithelium.[8]
History
The choriocapillaris was first described in man by Hovius in 1702, although it was not so named until 1838, by Eschricht. Passera (1896) described its form as star-shaped, radiating capillaries beneath the pigment epithelium of the retina, and Duke-Elder and Wybar (1961) have emphasized its nature as a network of capillaries in one plane.[1]
References
- ^ a b c ImranBhutto,GerardLutty (1967-09-01). "CHORIOCAPILLARIS AND LAMINA ELASTICA (VITREA) OF THE RAT EYE" (PDF). British Journal of Ophthalmology. 51 (9): 599–616. doi:10.1136/bjo.51.9.599. PMID 6050874.
- ^ a b Standring, Susan (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice (42th ed.). New York. pp. 794–795. ISBN 978-0-7020-7707-4. OCLC 1201341621.
{{cite book}}
: CS1 maint: location missing publisher (link) - ^ Standring, Susan (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice (42th ed.). New York. pp. 794–795. ISBN 978-0-7020-7707-4. OCLC 1201341621.
{{cite book}}
: CS1 maint: location missing publisher (link) - ^ Al Lens, Sheila Coyne Nemeth, janice K Ledford, Ocular Anatomy and Physiology (2008). the posterior segment (2 ed.). SLACK. p. 87.
{{cite book}}
: CS1 maint: multiple names: authors list (link) - ^ Lee Ann Remington, CLINICAL ANATOMY AND PHYSIOLOGY OF THE VISUAL SYSTEM (2012). Chapter3 Uvea (3 ed.). Elsevier. p. 53.
- ^ Parver LM (1991-03-01). "Temperature modulating action of choroidal blood flow". Eye. 5 (2): 181–5. doi:10.1038/eye.1991.32. PMID 2070878.
- ^ M. A. Zouache, I. Eames, C. A. Klettner, and P. J. Luthert (2016-10-25). "Form, shape and function: segmented blood flow in the choriocapillaris". Scientific Reports. 6: 35754. Bibcode:2016NatSR...635754Z. doi:10.1038/srep35754. PMC 5078844. PMID 27779198.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ Bill A, Sperber G, Ujiie K. (1983-02-06). "Physiology of the choroidal vascular bed". International Ophthalmology. 6 (2): 101–7. doi:10.1007/BF00127638. PMID 6403480. S2CID 499637.
{{cite journal}}
: CS1 maint: multiple names: authors list (link)
External links
- https://web.archive.org/web/20070927210324/http://www.trinity.edu/rblyston/MicroA/Lectures/L31-html/sld015.htm
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(outer)
Sclera |
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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:retina](http://upload.wikimedia.org/wikipedia/commons/thumb/e/e8/Eye-diagram_no_circles_border.svg/200px-Eye-diagram_no_circles_border.svg.png)
tunic (middle)
Choroid |
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Ciliary body | |
Iris |
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of the eye
Anterior segment | |
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Posterior segment |
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