Own eye shell. Horioide Eyes: Building, Features and Possible Diseases

Vascular casing (tunica Vasculosa Bulbi.). Embryogenetically, it corresponds to a soft cerebral shell and contains thick plexus of vessels. It is divided into three departments: a rainbow shell ( iris.), ciliary or ciliary body ( corpus Ciliare.) and the actual vascular shell ( chorioidea.). Each of these three departments of the vascular path performs certain functions.

Iris It is an forward well visible department of the vascular path.

The physiological value of the iris is that it is a kind of diaphragm regulating depending on the conditions of the flow of light into the eyes. The optimal conditions for high visual acuity are provided with a pupil width of 3 mm. In addition, the rainbow shell takes part in ultrafiltration and outflow of intraocular fluid, and also ensures the constancy of the moisture temperature of the anterior chamber and the tissue itself by changing the width of the vessels. The rainbow shell is a pigmented round plate located between the horn shell and lens. In the center it is a round hole, pupil ( pupilla.), whose edges are covered with pigment fringe. The iris has an exceptionally peculiar pattern, due to radially located quite thickly intertwined vessels and connecting crossbars (lacuna and trabecules). Due to the looser of the iris cloth in it, there are many lymphatic spaces opened on the front surface with various sizes or lacunas, crypts.

In the forefront of the iris contains many process pigment cells - chromatophores containing golden xanthophores and silver guanofors. The rear portion of the iris has a black color due to a large number of pigment cells filled with fuscine.

In the front mesodermal sheet of the rainbow shell of the newborn, the pigment is almost absent and through the stroma shines the rear pigment plate, caused by the bluish color of the iris. Permanent painting of the iris acquires to 10-12 years of child's life. In places of accumulation of the pigment, "freckles" of the iris are formed.

In old age, there is a depigmentation of the iris due to sclerotic and dystrophic processes in an aging organism, and it again acquires a lighter color.

There are two muscles in the rainbow shell. Circular muscle, narrowing pupil (m. Sphincter Pupillae), consists of circular smooth fibers located concentrically the pupil edge for a width of 1.5 mm - the pupil belt; Innervated by parasympathetic nerve fibers. The muscle expanding the pupil (m. Dilatator Pupillae) consists of pigmented smooth fibers lying radially in the rear layers of iris and having sympathetic innervation. In young children, the muscles of the iris are weakly expressed, the dilator almost does not function; The sphincter prevails and the pupil is always already than in older children.

The peripheral part of the iris is a ciliary (eyelating) belt width up to 4 mm. A collar (mesentery) is formed on the border of the pupil and ciliary zone by 3-5 years, in which the small arterial circle of the rainbow shell is located, formed by the anastomosing branches of the large circle and ensuring the blood supply to the pupil belt.

The large arterial circle of the iris is formed on the border with a ciliary body at the expense of the branches of the rear long and front cylinder artery, anastomosing among themselves and giving return branches to the actual vascular shell.

Innervates a rainbow sheath sensitive (ciliary), motor (glacial) and sympathetic nerve branches. The narrowing and expansion of the pupil is carried out mainly by means of parasympathetic (glazation) and sympathetic nerves. In the case of damage to parasympathetic paths while maintaining sympathetic, the reaction of the pupil into light, convergence and accommodation is completely lacking. The elasticity of the rainbow shell, which depends on the age of a person, also affects the magnitude of the pupil. In children under 1, the pupil is narrow (up to 2 mm) and poorly reacts to light, weakly expanding, in the youth and young age, it is worst than an average (up to 4 mm), and other impacts are vividly. To old age, when the elasticity of the iris sharply decreases sharply, pupils, on the contrary, are sore and their reactions are weakened. None of the parts of the eyeball does not contain as many indicators to understand the physiological and especially pathological state of the central nervous system of a person as pupil. This unusually sensitive apparatus easily reacts to various psycho-emotional shifts (fear, joy), diseases of the nervous system (tumor, congenital syphilis), diseases of internal organs, intoxication (botulism), children's infections (diphtheria), etc.

Ciliary body - This is, figuratively speaking, iron internal secretion of the eye. The main functions of the ciliary body are the production (ultrafiltration) of intraocular fluid and accommodation, i.e. the creation of conditions for a clear vision near and away. In addition, the ciliary body takes part in blood supply to the tissues, as well as in maintaining normal ophthalmotonus due to both products and outflow of intraocular fluid.

The ciliary body is like a continuation of the iris. It can be familiar with its structure only with ton and cyclospia. The ciliary body is a closed ring with a thickness of about 0.5 mm and a width of almost 6 mm, located under the scler and separated by the supracillion space. On the meridional cut, the ciliary body has a triangular shape with a base towards the iris, one vertex - to the choroid, the second to the lens and contains the cylinder (accommodation muscle - m. ciliaris.), consisting of smooth muscle fibers. There are more than 70 cylinder processes on the bug artistic front inner surface of the ciliary muscle ( processus Ciliares.). Each cyiliary process consists of a stroma with a rich network of vessels and nerves (sensitive, motor, trophic), coated with two sheets (pigment and unmanned) epithelium. The front segment of the ciliary body, which has pronounced processes, is called a cyiliary crown ( corona Ciliaris.), and the rear intact part is a ciliary circle ( orbiculus Ciliaris.) or flat department ( pars Plana.). The stromrom of the ciliary body, like the iris, has a large number of pigment cells - chromatophores. However, cyiliary processes of these cells do not contain.

Strom is covered with an elastic glass plate. Next, Knuts The surface of the ciliary body is covered with ciliary epithelium, pigment epithelium and, finally, the inner vitreous membrane, which are a continuation of similar retinal formations. The zonular fibers are attached to the cyiliary bodies membrane ( fibrae zonulares.), on which a crystal is fixed. The rear border of the ciliary body is the toothed line (Ora Serrata), where the vascular itself begins and the optical part of the mesh shell ends ( pars Optica Retinae.).

The blood supply to the ciliary body is carried out at the expense of the rear long ciliary arteries and anastomoses with the vascular network of the iris and choroid. Thanks to the rich network of nervous endings, the ciliary body is very sensitive to any irritation.

The newborn ciliary body is not developed enough. The ciliary muscle is very thin. However, by the second year of life, it increases largely and thanks to the appearance of combined cuts of all muscles, the ability to accommodate is acquiring. With the growth of the ciliary body, its innervation is formed and differentiated. In the first years of life, sensitive innervation is less perfect than the motor and trophic, and this is manifested in the painlessness of the ciliary body in children with inflammatory and traumatic processes. In seven-year children, all the relationships and the size of the morphological structures of the ciliary body are the same as in adults.

Actually vascular shell (chorioidea.It is the posterior department of the vascular path visible only with biomicro- and ophthalmoscopy. It is located under the scler. The fraction of choroids accounts for 2/3 of the total vascular path. Horioide takes part in the nutrition of the insavidial structures of the eye, the photoenergy layers of the retina, in ultrafiltration and outflow of intraocular fluid, in maintaining a normal ophthalmotonus. Chorioide is formed at the expense of the rear short ciliary arteries. In the forefront, the vessels of the vascular shell anastomize with the vessels of a large arterial circle of iris. In the backyard around the disk of the optic nerve there are anastomoses of the vessels of the choriocapillary layer with the capillary network of the optic nerve from the central artery of the retina. Chorioide thickness up to 0.2 mm in the rear pole and up to 0.1 mm in front. There is a perichoroidal space between the vascular shell and the scler (spatium perichorioidale) filled with intraocular fluid. In an early childhood age of perichoroidal space, it is almost at all, it develops only to the second half of the life of the child, opens in the first months, first in the field of the ciliary body.

Horioide - multi-layered education. The outer layer is formed by large vessels (vascular plate, lamina Vasculosa.). Between the vessels of this layer there is a loose connective tissue with cells - chromatophoras, the color of the vascular shell depends on their quantity and painting. As a rule, the amount of chromatophores in the vascular shell corresponds to the general pigmentation of the human body and in children relatively small. Thanks to the pigment, the vascular envelope forms a peculiar dark chamber-obscura, which prevents the reflection of the rays incoming through the pupil and ensuring a clear image on the retina. If the pigment in the vascular shell is not enough (more often in blonde faces) or at all, it happens the albinotic picture of the eye bottom. In such cases, the function of the eye is significantly reduced. In this shell in the layer of large vessels there are 4-6 erectous, or water times, veins ( v. Vorticosae.) Through which the venous outflow is carried out mainly from the rear department of the eyeball.

Next goes a layer of medium vessels. Connecting tissue and chromatophores here less and veins are dominated over the arteries. The middle vascular layer is located a layer of small vessels, from which branches in the most internal - chori-poinal layer ( lamina Choriocapillaris.). The choriocapillary layer has an unusual structure and through its lumen (lacuna), not one shaped element of blood, as usual, but several in one row. By the diameter of the number of capillaries per unit area, this layer is the most powerful compared to others. The top wall of the capillaries, i.e., the inner shell of the choroid, is a vitreous plate that serves as a border with a retinal pigment epithelium, which, however, is intimately associated with the vascular shell. It should be noted that the most thick vascular network in the backyard of choroids. It is very intense in the central (macular) area and the poor in the field of visual nerve and near the toothed line.

The vascular shell contains, as a rule, the same amount of blood (up to 4 drops). An increase in the volume of choroids per drop can cause an increase in pressure inside by more than 30 mm Hg. Art. The relatively large amount of blood continuously passing through the choroid provides constant nutrition of the retinal pigment epithelium associated with the chorioide, where active photochemical processes occur. Innervation of choroids is basically a trophic. Due to the lack of sensitive nerve fibers, its inflammation, injuries and tumors proceed painlessly.

Medium, or vascular, eye sheath-TUnica Vasculosa Oculi-is located between fibrous and mesh shells. It consists of three departments: Actually vascular shell (23), carnish Body (26) and rainbow shell (7). The latter is in front of the lens. The actual vascular envelope is the largest part of the middle shell in the area of \u200b\u200bthe sclera, and the clarity body lies between them, in the area of \u200b\u200bthe lens.

System of senses

Self-vascular shell,or horioida-chorioidea-in the form of a fine membrane (up to 0.5 mm), rich vessels, dark, is located between the scler and the retina. The choroid is pretty "loose, with the exception of vessels and optic nerve spaces, as well as the sclector in the cornea, where the connection is stronger. With a mesh-shell, it connects rather tightly, especially with the pigment layer of the latter. To remove this pigment on Vascular shell noticeably acts reflective shellor tipetum -tAPE-TURN FIBROSUM, is a place in the form of an equilibrium triangular blue-green, with a strong metal glitter, fields doodally from the optic nerve, up to the ciliary body.

Fig. 237. Front Half of the Left Eyes Rear Eyes.

Rear view (crystal removed);1 -farming shell;2 -rest crown;3 -pigent layer of the iris;3" -vinogradi grain;4 -pupil.

Ciliare Corpus Corpus Ciliare (26) - It provides a thickened, rich vessels of a medium shell, located in the form of a belt to 10 mm wide on the border between the actual vascular shell and iris. The radial folds in the form of scallops in the amount of 100-110 are well distinguishable on this belt. In their totality they form ring Corn- Corona Ciliaris (Fig. 237-2). In the direction of the vascular shell, i.e., behind, the cilly scallops decrease, and in front they end cilia process-Processus Ciliares. Thin fiber-fibrae zonulares are attached to them, - formative wildworn,or crustal zinnovy ligament - zonula ciliaris (zinnii) (Fig. 236- 13),- or a ligament hanging the lens. SuspensoriumLentis. Between the bunches of the fibers of the ciliary belt remain the lymphatic slit-spatia zonularia s. Canalis Petiti, - filled with lymphic.

In the ciliary body laid writing muscles-m. Ciliaris-of smooth muscular fibers, which makes up with a lens accommodation apparatus of the eye. It is innervated only by parasympathetic nerve.

Rainbow shell-iris (7) - The middle shell of the eye, located directly in front of the lens. In the center of it is a ped-robian-shaped hole pupil-Pupilla (Fig. 237-4), - takes up to 2 / b of the transverse diameter of the iris. On the rainbow shell distinguish the front surface of the L-Facies Anterior, - facing the cornea, and the rear surfaces of the L-Facies Posterior, -rigible to the lens; It grows the rainbow part of the retina. On both surfaces are noticeable tender folds-Plicae Iridis.

The edge, framing the pupil, is called the pupil M-Margo Pu-Pillaris. From the mercenary area hanging on the legs grape zerina- Granula Iridis (Fig. 237-3) - in the form 2- 4 rather dense black and brown formations.

The edge of attaching a rainbow shell, or painting Krai Y- Margo Ciliaris r. - Offed with a ciliary body and with a cornea, with the last through scallop ligaments-Ligamentum Pectinatum Iridis, - Cost ofseparate crossbars, between which the lymphatic slit-fountains of space remain but-Spatia Anguli Iridis (Fontanae).

Horse vision 887

Pigment cells are scattered in the iris, from which the "color" of the eyes depends. It is a brown-yellowish, less freaky. In the type of exclusion, the pigment can be missing.

Smooth muscular fibers embedded in a rainbow shell form a pupil-m sphincter. SPHIncter Pupillae-Circular fibers and dila tattorpupil-M. Dilatator Pupillae-from radial fibers. With its abbreviations, they determine the narrowing and expansion of the pupil, what is regulated by the receipt of rays in the eyeball. With a strong light, the pupil is narrowed, with a weak, on the contrary, expands and becomes more rounded.

Blood vessels of the Rainbow Shell go radially from the arterial ring located in parallel to the Circulus Arteriosus Iridis Maior.

The pupil sphincter is innervated by a parasympathetic nerve, and dila-tator-sympathetic.

Mesh Eyes Shell

Mesh eye sheath, or retina, -retina (Fig. 236- 21) - The inner shell of the eyeball. It is subdivided into the visual part, or the retina itself, and the blind part. The latter disintegrates on the part of the ciliary and rainbow.

3 P and Tached of the retina and-Pars Optica Retinae- consists of a pigment layer (22), tightly struggling with the actual vascular shell, and from the retina itself, or retina (21), easily separated from the pigment layer. The latter extends from the entrance of the optic nerve to the ciliary body, from which it ends with a rather smooth edge. During the lifetime, the retina represents a delicate transparent shell of pinkish color, turbulent after death.

The retina is tightly attached in the field of inlet of the visual nerve. This is a location with a cross-mold, called visual nipple-Papilla Optica (17) - by a diagonal of 4.5-5.5 mm. In the center of the nipple, there is a small (up to 2 mm height) of the processsus Hyaloideus- rudiment of the arteries of the vitreous body.

In the center of the retina on the optical axis, the central field is highlighted in the form of a light strip-Area Centralis Retinae. It is a site of the best vision.

Retail Retail and-Pars Ciliaris Retinae (25) - and Rainbow Some Retinae and-Pars Iridis Retinae (8) - Very Thin; They are built of two layers of pigment cells and grow together. The first-with ciliary body, the second-with iris. On the pupil edge of the latter, the grape grapes mentioned above forms.

Speed \u200b\u200bnerve

Spectator nerve Opticus. (20), -Diameter up to 5.5 mm, penetrates the vascular and squirrel and then leaves the eyeball. In the eyeball of the fiber, his shaggy, and outside the eyes they are meal. Outside the nerve is dressed by solid and soft cerebral shells forming the vagina of the visual nerve A-Vaginae Nervi Optici (19). The latter are separated by lymphatic slits communicating with subtle-rally and subarachnoid spaces. Inside the nerve there are central artery and vein retina, a horse has only nerve.

Crystalik.

Crystalik.-Lens Crystalline (14,15) -In the shape of a two-way lens lens with a flatter front surface of the U-F Acies Anterior (13-15 mm radius) - and more convex back-facies Posterior (5,5- radius

System of senses

10.0 mm).The lens differ from the front and rear poles and the equator.

The horizontal diameter of the lens is up to 22 mm long, vertical - up to 19 mm, the distance between the poles along the axis crystal and to A-AXIS Lentis-up to 13.25 mm.

Outside Drose-Capsula Lentis {14). Parenhim Crystal A-Substantia Lentis (16)- disintegrates on the consistency on a soft cork part-Substantia corticalis-and dense crustal core-Nucleus Lentis. Parenchima consists of flat cells in the form of plates-Laminae Lentis, resolved concentrically around the kernel; One end of the plates is directed forward butother back. The dried and compacted crystal can be dissected on the sheets like a bulb. Crystal is completely transparent and pretty merchant; After death, he gradually mutters and on it become noticeable spikes of plates cells forming on the front and rear surface of the lens three beam of A- Radii Lentis, on the center.

The vascular shell of the eye or chorioide is the middle shell of the eye, lying between the scler and the retina. Most part of the chorioide is represented by a well-developed network of blood vessels. The blood vessels are located in choroids in a certain order - outside are larger vessels, and inside, on the ribbon with the retina, is a layer of capillaries.

The main function of the vascular shell is the supply of four outer layers of retina, including a layer of sticks and colodes, as well as the removal of the exchange products from the mesh shell back to the bloodstream. From the retina, the capillaries layer is delivered by a thin membrane of Bruch, the function of which is the regulation of metabolic processes between the retina and the vascular sheath. In addition, the okolosuddist space, due to its loose structure, serves as a conductor for the rear long ciliary arteries involved in the blood supply to the front of the front of the eye.

The structure of the vascular shell

Actually vascular shell is the most extensive part of the vascular path of the eyeball, which also includes a ciliary body and a rainbow sheath. It spreads from a ciliary body, the boundary of which is a toothed line, to the disk of the optic nerve.
Horioid is ensured by blood flow, due to the rear short ciliary arteries. Blood outflow occurs according to the so-called, revigious veins. A small number of veins - just one on each quarter, or quadrant, eyeball and pronounced blood flow contribute to the slowdown of the blood current and the high probability of the development of inflammatory infectious processes due to the sedimentation of pathogenic microbes. The vascular shell is devoid of nerve sensitive expirations, for this reason all its diseases proceed painlessly.
Horioid is rich in a dark pigment, which is located in special cells - chromatophoras. The pigment is very important for vision, as the light rays falling through the open areas of the iris or sclera, would interfere with good vision due to the diffused lighting of the retina or side lights. The amount of pigment contained in this layer, in addition, determines the intensity of the painting of the eye bottom.
Accordingly, its name, mostly, chorioide consists of blood vessels. The horooida includes several layers: a near-suite space, an existence, vascular, vascular-capillar and basal layers.

The occasional or periheroidal space is a narrow slit between the inner surface of the sclera and the vascular plate, which is permeated with gentle endothelial plates. These plates bind the walls among themselves. However, due to weak bonds, the sclera and choroids in this space, the vascular shell is quite easily peeling from the sclera, for example, when the intraocular pressure drops in the process of glaucoma operations. In the perichoroidal space from the rear to the leading, the eyes pass two blood vessels - long rear ciliary arteries, accompanied by nervous trunks.
The superior plate consists of endothelial plates, elastic fibers and chromatophores - cells containing dark pigment. The number of chromatophores in the choroid layers in the direction outside Knutsa is rapidly decreasing, and they are completely absent at the choriocapillary layer. The presence of chromatophores can lead to the emergence of non-units of choroids and even the most aggressive malignant tumors - melan.
The vascular plate has a view of a brown membrane, a thickness of up to 0.4 mm, and the layer thickness depends on the degree of blood flow. The vascular plate consists of two layers: large vessels lying outside with a large number of arteries and vessels of the middle caliber, in which veins prevail.
The vascular capillary plate, or the choriocapillary layer, is the most important layer of choroids, ensuring the functioning of the retinal subject to the retinal. It is formed from small arteries and veins, which are then disintegrated by a set of capillaries that transmit several erythrocytes into one row, which makes it possible to act as a larger amount of oxygen. Particularly expressed a network of capillaries for the functioning of the macular region. The close relationship of the choroid with the retina leads to the fact that inflammatory diseases are usually affected by the retina and vascular shell together.
The membrane of Bruha is a thin plate consisting of two layers. It is very tightly connected to the choriocapillary layer of choroids, participates in regulating oxygen intake in the retina and the exchange products back to the bloodstream. The membrane of Brucha is also associated with the outer retinal layer - pigment epithelium. With age and in the presence of predisposition, there may be a violation of the function of the complex of structures: the choriocapillary layer, the membrane of Bruchi and pigment epithelium, with the development of age macular degeneration.

Methods of diagnosis of diseases of the vascular shell

• Ophthalmoscopy.
• Ultrasound diagnostics.
• Fluorescent angiography is an assessment of the state of the vessels, damage to the membrane of Brucha, the appearance of newly formed vessels.

Symptoms for diseases of the vascular shell

Congenital changes:

• Coloboma vascular shell - complete absence of chorioide on a certain area.

Acquired changes:

• Distrophy vascular shell.
• The inflammation of the vascular shell is choroidites, but more often combined with damage to the retina - chorioretinites.
• Pulling the vascular shell, with intraocular pressure drops during extensive operations on the eyeball.
• Breaks of the vascular shell, hemorrhage - most often due to eye injury.
• Nesus chorioide.
• Tumors of the vascular shell.

The actual vascular shell (choroid) is the largest posterior sector of the vascular shell (2/3 of the volume of the vascular path), throughout the gear line to the optic nerve, is formed by rear short ciliary arteries (6-12), which pass through the rear poles of the eye .

Between the vascular shell and scler there is a perichoroidal space filled with an intraocular fluid.

Horioide has a number of anatomical features:

• deprived of sensitive nerve endings, so the pathological processes developing in it do not cause painful sensations
• its vascular network does not anatomize with front ciliary arteries, as a result, during choroidids, the front eye of the eye remains intact
• an extensive vascular bed with a small number of vessels of vessels (4 uniform veins) promotes the slowdown in the blood flow and sedimentation here the pathogens of various diseases
• it is limited to the retina, which for diseases of the choroids, as a rule, is also involved in the pathological process.
• due to the presence of perichoroidal space, it is fairly easily peeling from the sclera. It is maintained mainly due to the exhaust venous vessels, perforing it in the equator area. A stabilizing role is also played by vessels and nerves penetrating in the chorioide from the same space.

Functions

1. nutrient and exchange - Delivered with blood plasma food to the retina to a depth of it to 130 μm (pigment epithelium, retinal neuroepithelies, an outer plexiform layer, as well as the entire foxal retina) and removes the products of metabolic reactions, which ensures the continuity of the photochemical process. In addition, the peripapillary horooiding feeds the prebaminar region of the optic nerve disk;
2. temoregulation - removes with the blood flow of excess thermal energy, formed during the functioning of photoreceptor cells, as well as when absorbing light energy, the retinal pigment epithelium during the visual work of the eye; The function is associated with a high rate of blood flow in choriocapillary, and presumably with the solo structure of the horoidy and the prevalence of the arterilar component in the macular horoidy;
3. structure-forming - maintaining the turgora of the eyeball due to the blood flow of the shell, which ensures the normal anatomical ratio of the departments of the eye and the required level of exchange;
4. maintaining the integrity of the external hematoretical barrier - maintaining the constant outflow from the subretal space and the removal of "lipid garbage" from the retinal pigment epithelium;
5. regulation of ophthalmotonus, at the expense of:
   • reducing smooth muscle elements located in a layer of large vessels,
   • changes tension vascular shell and its blood flow,
   • influence on the rate of perfusion of ciliary processes (thanks to the front vascular anastomy),
   • heterogeneity of the sizes of venous vessels (volume regulation);
6. auToregulation - regulation of the fovyal and peripapillary horoida of its bulk blood flow by reducing perfusion pressure; The function is allegedly related to nitrrgic vasodilator innervation of the central department of the HoroDeei;
7. bloodstock level stabilization (depreciable) due to the presence of two systems of vascular anastomoses hemodynamics of the eye is held in a certain unity;
8. light absorption - Pigment cells located in the mooring layers absorb the light stream, reduce the light scattering, which helps to obtain a clear image on the retina;
9. structurally barrier - due to the existing segmental (Dolkova) structure of the Horoida retains its functional fullness when the pathological process of one or more segments is damaged;
10. explorer and transport function - Through it takes back long cylinder arterys and long ciliary nerves, it carries out the perichoroidal space of the injequeous outflow of intraocular fluid.

The extracellular matrix of the vascular shell contains a high concentration of plasma proteins, which creates high oncotic pressure and ensures filtering of metabolites through a pigment epithelium in the choroid, as well as through supracillion and suprachoroidal spaces. From the suprahrioide, the liquid diffuses in the scler, the scleral matrix and the perivascular slots of emission and episcople vessels. A person has an injistic outflow of 35%.

Depending on the oscillations of hydrostatic and oncotic pressure, the intraocular fluid may be reabidated by the choriocapillary layer. In the vascular shell, as a rule, contains a constant amount of blood (up to 4 drops). An increase in the size of choroids per drop can cause an increase in intraocular pressure by more than 30 mm RT. Art. A large amount of blood continuously passing through the choroid provides constant nutrition of the retinal pigment epithelium associated with choroid. The thickness of the choroid depends on blood flow and averages 256.3 ± 48.6 μm in the emmetropic eyes and 206.6 ± 55.0 μm in myopic eyes, decreasing up to 100 microns on the periphery.

Vascular sheath with age is thinned. According to B. Lumbroso, the thickness of the choroid is reduced by 2.3 microns per year. The thinning of the choroid is accompanied by a circulatory disorder in the rear pole of the eye, which is one of the risk factors for the development of newly formed vessels. Significant thinning of the vascular shell of the eye, associated with the increase in age in the emmetropic eyes in all points of measurement. People up to 50 years old, the thickness of the choroid is an average of 320 microns. In persons over 50 years old, the thickness of the vascular shell decreases to 230 microns. In the group of persons over 70 years old, the average value of the choroid is 160 microns. In addition, a decrease in choroid thickness with an increase in the degree of myopia is noted. The average thickness of the vascular shell at the emmetrops is 316 microns, in persons with a weak and medium degree of myopia - 233 μm and in persons with a high degree of myopia - 96 microns. Thus, there are large differences in the thickness of the vascular shell depending on age and refraction.

The structure of chorioide

The vascular shell extends from the toothed line to the opening of the visual nerve. In these places, it is tightly connected to the scler. The loose attachment is available in the equator area and in the fields of the vessels and nerves in the vascular shell. Over the rest, she arrives at the scler, separating the narrow slit from it - suprahoroidal proweb. The latter ends at 3 mm from the limb at the same distance from the venue of the visual nerve. A ciliary vessels and nerves pass on the suprachoroidal space, there is an outflow of fluid out of the eye.

Horioide - Education consisting of five layersThe basis of which is a thin connecting stromter with elastic fibers:

• suprahchoroid;
• layer of large vessels (galleri);
• layer of medium vessels (trendler);
• choriocapillary layer;
• floth plate, or membrane Bruha.

On the histological cut, the chorioide consists of the lumen of the vessels of various sizes separated by a loose connective tissue, the process cells with a crumb-shaped brown pigment - melanin are visible. The number of melanocytes, as is known, determines the color of the vascular shell and reflects the nature of human body pigmentation. As a rule, the number of melanocytes in the vascular shell corresponds to the type of body's general pygmentation. Thanks to the pigment, the chorioide forms a peculiar chamber-obscura, which prevents the reflection of the rays incoming through the pupil and ensuring a clear image on the retina. If a pigment in the vascular shell is not enough, for example, in the celery-skinned persons, or at all, which is observed in albinos, its functionality is significantly reduced.

The choroid vessels constitute its main mass and are branches of the rear short ciliary arteries penetrating through the wool at the rear pole of the eye around the visual nerve and the further dichotomous branching, sometimes before the penetration of the arteries in the scler. The number of rear short ciliary arteries ranges from 6 to 12.

The outer layer is formed by large vessels Between which there is a loose connective tissue with melanocytes. The layer of large vessels is mostly formed by arteries, which are distinguished by an unusual width of the lumen and the narrowness of intercupillary gaps. It creates an almost solid vascular bed, separated from the retina only Lamina Vitrea and a thin layer of pigment epithelium. The layer of large vessels of the choroids are located 4-6 revorted veins (V. Vorticosae) through which the venous outflow is carried out mainly from the rear ventilation apple. Large veins are located near the sclera.

Layer of medium vessels It goes outside the outer layer. It has melanocytes and connective tissue much less. Vienna in this layer prevail over the arteries. Behind the middle vascular layer is located layer of small vessels from which branches are departed in the most inner - choriocapillary layer Lamina Choriocapillaris).

Choriocapillary layer On the diameter and number of capillaries per unit area dominates the first two. It is formed by a system of prokapillars and postcases and has a view of wide lacuna. In the lumen of each such lacuna, up to 3-4 red blood cells. On the diameter and number of capillaries per unit area, this layer is the most powerful. The most thick vascular network is located in the backyard of choroids, less intense - in the central macular area and poor - in the field of visual nerve, close to the toothed line.

The arteries and veins of the vascular shell have a common structure inherent in these vessels. Venous blood flows out of choroids through the colors. The venous branches of the choroids flowing into them are connected to each other yet within the vascular shell, forming a bizarre system of the water films and expansion at the site of the merge of the venous branches - an ampoule, from which the trunk venous trunk departs. Virtous veins through oblique gloral channels leave the eyeball on the sides of the vertical meridian behind the equator - two above and two below, sometimes their number reaches 6.

The inner shell of choroids serves fiscame plate, or membrane Bruha , excluding the choroid from the retina pigment epithelium. Conducted electron microscopic studies show that the membrane of Bruch has a layered structure. On the vitreous plate, the cells of the retinal pigment epithelium are tightly connected to it. On the surface, they have the form of regular hexagons, they contain a significant amount of melanin granules.

From the pigment epithelium, the layers are distributed in the following order: the baseal pigment epithelium membrane, the inner collagen layer, layer of elastic fibers, the outer collagen layer and the basal membrane of the choriocapillary endothelium. Elastic fibers are distributed through the membrane by beams and form a network layer somewhat shifted to the outside. In the front departments it is more dense. The fibers of the membrane of Bruchi are immersed in the substance (amorphous substance), which is a mucoid gel-like medium, which includes acidic mucopolysaccharides, glycoproteins, glycogen, lipids and phospholipids. The collagen fibers of the outer layers of the membrane of Bruchi come out between the capillaries and are woven into the connecting structures of the choriocapillary layer, which contributes to the dense contact between these structures.

Supervisoroidal space

The outer boundary of the choroids is separated from the sclera of a narrow capillary slit, through which suprahoroid plates consisting of elastic fibers covered with endothelium and chromatophoras are coming from choroids. Normally, the suprahoroidal space is almost not pronounced, but in conditions of inflammation and edema, this potential space reaches significant sizes due to the accumulation here exudate, spreading suprahrioidal plates and pushing the choroid knutrice.

The suprahoroidal space begins at a distance of 2-3 mm from the yield of an opaque nerve and ends, without reaching about 3 mm to the place of attachment of the ciliary body. Through the suprahoroidal space, long ciliary arteries and ciliary nerves shrouded in a tender fabric of supersturoids pass to the front separation of the vascular tract.

The vascular envelope is easily moving away from the sclera, with the exception of its rear section, where the dichotomically divided vessels entering it bonded the vascular shell with the sclera and prevent its detachment. In addition to the detachment of choroids may interfere with the vessels and nerves on the rest of it, penetrating the choroid and ciliary body from the suprahrioid space. With explicit hemorrhage, the tension and possible separation of these nervous and vascular branches determine the reflex violation of the overall state of the patient - nausea, vomiting, the drop in the pulse.

The structure of vessels of choroids

Arteries

The arteries do not differ from the arteries of other localizations and have an average muscle layer and adventitia containing collagen and thick elastic fibers. The muscular layer of endothelium is separated by an internal elastic membrane. The fibers of the elastic membrane are intertwined with the fibers of the basal membrane of endotheliocytes.

As the caliber decreases, the arteries are converted into arterioles. It disappears the solid muscular layer of the wall of the vessels.

Vienna

Veins are surrounded by perivascular shell, which is located connecting tissue. The lumen of the veins and Vevel was lined with endothelium. The wall contains unevenly distributed smooth muscle cells in a small amount. The diameter of the largest veins is 300 μm, and the smallest, breastpillary veins - 10 microns.

Capillaries

The structure of the choriocapillary network is very peculiar: the capillaries forming this layer are located in the same plane. Melanocytes in the choriocapillary layer are absent.

The capillaries of the choriocapillary layer of the vascular shell have a rather large lumen, which allows for several erythrocytes. They are elected endothelial cells, outside of which pericitis lie. The number of pericitis per endothelial cell of the choriocapillary layer is quite large. So, if in the retinal capillaries, this ratio is 1: 2, then in the vascular shell - 1: 6. Percites are larger in the Fovoyolar region. Pericitis relate to contracting cells and participate in the regulation of blood supply. The feature of the capillaries of choroids is that they are phenostritated, as a result of which their wall is undergoing for small molecules, including fluorosecene and some proteins. The pore diameter ranges from 60 to 80 microns. They are closed with a thin layer of cytoplasm thickened in central sites (30 microns). Fenstras are located in chori-pointers from the side facing the membrane of Brucha. Between endothelial cells, arterioles are detected by typical zones of closures.

There are numerous anastomoses of choroid vessels, in particular, capillaries of the choriocapillary layer, with a capillary network of optic nerve, that is, the central artery of the retina.

The wall of arterial and venous capillaries is formed by a layer of endothelial cells, a thin basal and wide adventitial layer. The ultrastructure of arterial and venous departments of capillaries has certain differences. In arterial capillaries, those endothelial cells that contain the kernel are located on the side of the capillary facing a large vessels. Cells of cells with their long axis are oriented along the capillary.

From the side of the membrane of Bruchi, their wall sharply frozen and fenestrized. Compounds of endothelial cells on the part of the sclera are represented as complex or sealing joints with the presence of obliteration zones (classification of joints in Shahlamov). From the side of the membrane, the Brucha cells are connected by a simple touch of two cytoplasmic processes, between which there is a wide range of (the beam).

In venous capillaries, pericarion of endothelial cells is more often located on the sides of the glued capillaries. The peripheral part of the cytoplasm from the membrane of the Bruch and large vessels is very thinned and fenestrized, i.e. Venous capillaries can have thinned and fenst endothelium on both sides. The organized apparatus of endothelial cells is represented by mitochondria, a plate complex, centrilas, an endoplasmic network, free ribosomes and polysoms, as well as microfibrilles and vesicles. In 5% of the endothelial cells under study, the message channels of the endoplasmic network with basal vessel layers are established.

In the structure of the capillaries of the front, middle and rear shells, small differences are revealed. In the front and middle departments, capillaries with a closed (or semi-closed lumen, in the back, are prevailing capillaries with a wide open lumen, which is characteristic of vessels located in different functional state. Information accumulated to date makes it possible to consider endothelial capillar cells dynamic structures that are continuously changing their shape, diameter and length of intercellular intervals.

The prevalence in the front and middle sections of the shell of capillaries with a closed or semi-closed lumen may indicate the functional ambiguity of its departments.

Innervation Horioidemi

The vascular envelope is innervated by the sympathetic and parasympathetic fibers, outgoing from the ciliary, trigeminal, rope and upper cervical ganglia, in the eyeball, they come with eyelash nerves.

In the stroma of the vascular shell, each nerve barrel contains 50-100 axons, losing myelin shell when penetrating it, but preserving the Schwann shell. Postgangylionic fibers emanating from the ciliary ganglia remain amelinated.

The vessels of the extruded plate and the stroma of the vascular shell are extremely abundantly equipped with both parasympathetic and sympathetic nerve fibers. Sympathetic adrenergic fibers outgoing from cervical sympathetic nodes have a vasoconstrictor effect.

The parasympathetic innervation of the vascular shell comes from the facial nerve (the fibers coming from the Cutting Ganglia), as well as from the eye nerve (fibers coming from the ciliary ganglia).

Recent studies have significantly expanded knowledge regarding the characteristics of the innervation of the vascular shell. In various animals (rat, rabbit) and in humans, the arteries and arterioles of the vascular shell contain a large amount of nitragic and peptide-organic fibers forming a thick network. These fibers come with a facial nerve and pass through the goning gangliy and non-moving parasympathetic branches from the retrocal plexus. In a person, in addition, in the stroma of the vascular shell there is a special network of nitragic ganglion cells (positive when identifying NAP-diaphorazes and nitroxide synthetase), whose neurons are associated with each other and with perivascular network. It is noted that such a plexus is determined only in animals having Fovaol.

Ganglion cells are concentrated mainly in the temporal and central regions of the vascular shell, adjacent to the macular area. The total number of ganglion cells in the vascular shell of about 2000. They are unevenly distributed. The greatest amount is found with the temporal side and centrally. Little diameter cells (10 microns) are located along the periphery. The diameter of ganglion cells increases with age, possibly due to the accumulation of lipofuscin granules in them.

In some organs, the type of vascular shell, nitragic neurotransmitters are detected simultaneously with peptide, also with vasodilators. Peptide ergic fibers are likely to come from a riding ganglium and pass in the face and large rocky nerve. It is likely that nitro and peptide ergic neurotransmitters provide vasodilation when stimulating facial nerve.

Perivascular ganglion nervous plexus expands the vessels of the vascular shell, possibly adjusting the blood flow when changing intraarterial blood pressure. It protects the retina from damage to the thermal energy released during its lighting. Flugel et al. It was proposed that the ganglion cells located in the Fovaol are protected from the damaging action of the world that the area where the greatest focus of light occurs. It was revealed that when illuminated, the eye significantly increases the blood flow in the sections of the vascular shell adjacent to the Fovaole.

4. Eye apple shells. Fibrous shell, Tunica Fibrosa Bulbi. Scler, SCLERA. Cornea, Cornea.
5. Vascular casing of the eyeball. Actually vascular shell, choroidea. Ciliar cord, Corpus Ciliare.
6. Rainbow, Rainbow Shell, IRIS.
7. Vessels and nerves of the vascular shell. Blood supply vascular shell.
8. Retina, Mesh Shell, Retina. Retinal vessels. Retinal blood supply.
9. Inner eye core. Flawy body, Corpus Vitreum. Lesson, Lens. Accommodation.
10. Eye chambers. Front eye camera. Rear eye camera.
11. The auxiliary bodies of the eye. Muscles of the eyeball. Muscles eye.
12. The fiber of the eyeball and the vagina of the eyeball. Eyelids, Palpebrae ..
13. Connecting eye sheath, Tunica Conjunctiva. Conjunctiva eye.
14. Blood vessels and nerves of the eyelids and conjunctiva. Blood supply of the eyelids and conjunctions.
15. Temaric apparatus. Gladlany glaze, Glandula Lacrimalis. Temar bag, Saccus Lacrimalis.

Vascular casing of the eyeball. Actually vascular shell, choroidea. Ciliar cord, Corpus Ciliare.

II. Vascular Eye Apple Sheath, Tunica Vasculosa Bulbi, rich in vessels, soft, dark-colored from the shell-contained pigment, lies immediately under the scler. It distinguishes three departments: Actually vascular shell, ciliary body and iris.

1. Actually vascular shell, choroidea, It is a rear, large semiconductor. Thanks to constant movement choroidea. when accommodation here between both shells is formed slugging lymphatic space, Spatium Perichoroideale.

2. Ciliare Ciliare, Corpus Ciliare, - Front thickened part of the vascular shell, is located in the shape of a circular roller in the sclector crossing. Back with its edge forming the so-called firewall Circle, Orbiculus Ciliaris, the casual body continues directly in Choroidea. This place corresponds to the 6th SERRATA retina (see below). In front, the clarity body is connected to the outer edge of the iris. Corpus Ciliare. About 70 thin, radioly arranged white colors bears ahead of the ciliary mug. ciliaRes Ciliares Processus Ciliares.

Due to the abundance and a special device of vessels of cilma processes, they allocate liquid - camera moisture. This part of the ciliary body is compared with plexus Choroideus. brain and view as a sterling (from lat. Secessio - separation). Another part - accommodation - formed involuntary muscle, m. ciliaris.which lies in the thickness of the ciliary body in the duck from Processus Ciliares.. This muscle is divided into 3 portions: the external meridional, medium radial and internal circular. Meridional fibers that make up the main part of the cereal muscle start from SCLERA and end in the back in choroidea.. With its reduction, they stretch the latter and relax the lens capsule when installing the eye at close distances (accommodation). Circular fibers help accommodation, promoting the front part of the cyiliary processes, as a result of which they are especially developed in hyperamerpets (long-planic), which have to strongly strain the accommodation apparatus. Thanks to the elastic tendon, the muscle after its reduction comes to its original position and the antagonist is not required.

Muscle fibers are intertwined and form a single muscular elastic system, which in children consists more of meridional fibers, and in old age - from circular. At the same time, there is a gradual atrophy of muscle fibers and replacing them with a connective tissue than and the attenuation of accommodation is explained in high age. In women, the degeneration of the ciliac muscle begins on 5 - 10 years earlier than in men, with the onset of menopause.