1 - Sclera . 2 - Vascular membrane . 3 - Channel Schlemm . 4 - The root of the iris. 5 - The cornea . 6 - Iris . 7 - The pupil . 8 - The front camera of the eye . 9 - The back camera of the eye . 10 - The ciliary body . 11 - The lens . 12 - Vitreous body . 13 - The retina . 14 - Optic nerve . 15 - Zonular fibers.
Choroid , or choroid - the actual choroid of the eye. The choroid feeds the retina and restores constantly decaying visual substances. It is located under the sclera .
Choroid is present in all mammalian species. The capillary bed of the choroid, that is, choriocapillaries , indirectly supply photoreceptors with oxygen and nutrients.
The choroid is the posterior choroid and is represented by the posterior short ciliary arteries.
Content
Building
The choroid itself consists of the following layers:
- The vascular plate (lamina suprachorioidea) is the outer layer formed from elastic connective tissue and pigmented connective tissue cells.
- Vascular plate (lamina vasculosa) - contains a large number of arteries and veins, and, like the previous layer, elastic connective tissue and pigmented cells.
The glow of cat's eyes in the dark due to tapetum
- Tapetum ( lat. Tapetum lucidum - a luminous rug) is a special layer of choriodea, however, inherent in not all mammals . In particular, in humans, pigs and rabbits, this layer is absent. Tapetum is a poorly pigmented area, localized most often in the lower part of the eye. This layer consists of either flattened cells (e.g. in predators), partially containing guanine crystals (e.g. in dogs) or connective tissue fibers arranged in a special way (e.g., in horses, ruminants). These cells and fibers cause diffraction and reflection of light, acting as a "mirror", and re-direct light to the retina. This leads to an improvement in twilight vision . Tapetum is of great importance for those species of animals that are active at dusk. Tapetum also determines the characteristic glow of the animal's eyes in the dark when a small amount of light enters it.
- Vascular-capillary plate (lamina choroidocapillaris) - contains a thin capillary network, which provides nutrition to the outer layers of the retina.
- The basement membrane ( Bruch's membrane , lamina basalis) - directly adjoins to the retinal pigment layer and forms a connection with it. Thickness 2-4 microns.
Diseases
Inflammation of the choroid proper is called choroiditis.
Literature
- Sinelnikov R. D., Sinelnikov Ya. R. Atlas of human anatomy in 4 volumes . T.3. - M .: Medicine, 1996. - ISBN 5-225-02723-7
- Paul Simoens: Sehorgan, Organum visus. In: Franz-Viktor Salomon et al. (Hrsg.): Anatomie für die Tiermedizin . Enke-Verlag Stuttgart, 2. erw. Aufl. 2008, S. 579-612, ISBN 978-3-8304-1075-1
- Buttery RG, Hinrichsen CF, Weller WL, Haight JR. How thick should a retina be? A comparative study of mammalian species with and without intraretinal vasculature. Vision Res 1991; 31: 169-187.
Links
- Lutein Library Features of subretinal structures
- Eye: choroid