Capillary lamina of choroid

Part of the eye

Capillary lamina of choroid
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.
^ ^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

Anatomy of the globe of the human eye

Fibrous tunic
(outer)

Sclera	Episcleral layer Schlemm's canal Trabecular meshwork
Cornea	Limbus layers Epithelium Bowman's Stroma Dua's layer Descemet's Endothelium

Uvea / vascular
tunic (middle)

Choroid	Capillary lamina of choroid Bruch's membrane Sattler's layer
Ciliary body	Ciliary processes Ciliary muscle Pars plicata Pars plana
Iris	Stroma Pupil Iris dilator muscle Iris sphincter muscle

Retina (inner)

Layers	Inner limiting membrane Nerve fiber layer Ganglion cell layer Inner plexiform layer Inner nuclear layer Outer plexiform layer Outer nuclear layer External limiting membrane Layer of rods and cones Retinal pigment epithelium
Cells	Photoreceptor cells (Cone cell, Rod cell) → (Horizontal cell) → Bipolar cell → (Amacrine cell) → Retina ganglion cell (Midget cell, Parasol cell, Bistratified cell, Giant retina ganglion cells, Photosensitive ganglion cell) → Diencephalon: P cell, M cell, K cell, Muller glia
Other	Macula Perifoveal area Parafoveal area Fovea Foveal avascular zone Foveola Optic disc Optic cup Ora serrata

Anatomical regions
of the eye

Anterior segment	Adnexa (Eyebrow, Eyelid, Conjunctiva, Lacrimal system, Orbit) Fibrous tunic Anterior chamber Aqueous humour Iris Posterior chamber Ciliary body Lens Capsule of lens Zonule of Zinn
Posterior segment	Vitreous chamber Vitreous body Retina Choroid