VASCULAR TEXTURES of a brain (plexus choroidei, plexus chorioidei) — the vascular and epithelial educations located in ventricles of a brain which are derivatives of a soft meninx. A soft meninx (see. Meninx ) gets into ventricles of a brain (see) and participates in S.'s education of page (fig. 1).
A comparative anatomy
Phylogenetic development of S. of page is connected with transformations of a brain, especially its ventricles. At S.'s fishes of page are developed poorly, lie in a roof of the general cavity of a ventricle of a neoncephalon, and also in a roof of ventricles intermediate and a rhombencephalon.
At amphibious S. pages partially are implemented into cavities of two side ventricles of a neoncephalon. Villages of the village of ventricles intermediate (the third ventricle) and a rhombencephalon (the fourth ventricle) are located in their roof.
In the subsequent classes of vertebrata, starting with reptiles, S. pages of side ventricles are implemented into their cavities, connecting through interventricular foramens to S. page of the third ventricle. The vascular basis of the third and fourth ventricles forms the folds with the developed capillary network turned into a cavity of ventricles. The tail of a roof of the fourth ventricle of reptiles represents a thin wall, through to-ruyu cerebrospinal liquid diffuses. At mammals the skladchatost of a vascular basis of the third and fourth ventricles increases. Villages of the village are more developed.
On the 3rd week of embryonic development in a dorsal plate (a plate of a roof) of a neurotubule is available laying of an epithelium of S. of page (epithelium plexus choroidei). During a regional differentiation of front department of a neurotubule on the 4th week of embryonic development 3 brain bubbles form: front, average and rhomboid with the shank bores filled with cerebrospinal liquid. The wall of these cavities is formed by a layer of ependimalny cells. The blood vessels of a soft cover growing to an ependyma wring out it in a cavity of bubbles, forming folds of an ependyma, in to-rye S. of page are implemented. Before others (on 4 — 5th week) S. is formed by page of the fourth ventricle, then (on 6 — 7th week) — the third ventricle and, at last, on 7 — 9th week — side ventricles. At this S. the page of the third ventricle as if turns into similar formations of side ventricles.
the Vascular basis of the fourth ventricle (tela choroidea ventriculi quarti) is a fold of the soft meninx which is stuck out together with an ependyma in the fourth ventricle and has an appearance of a triangular plate adjacent to the lower brain sail. Its basis is directed forward and up, top — to a bottom corner of a rhomboid pole, and edge — to side edges of the lower brain sail. It makes the tail of a roof of the fourth ventricle together with the lower brain sail. In a vascular basis blood vessels, forming S. of page of the fourth ventricle (plexus choroideus ventriculi quarti) branch. In this texture allocate the middle, slanting and longitudinal part lying in the fourth ventricle and the longitudinal part extending in its lateral pockets. The village of the village of the fourth ventricle are formed by lobbies and back fleecy branches of the fourth ventricle (rr. choroidei ventriculi quarti ant. et post.). The front fleecy branch of the fourth ventricle departs from a front lower cerebellar artery (a. cerebelli inferior anterior) about a scrap (flocculus) and, branching in a vascular basis, creates S. of page of a lateral pocket of the fourth ventricle. The back fleecy branch of the fourth ventricle branches off from a back lower cerebellar artery (a. cerebelli inferior posterior) and branches in a middle part of S. of page. Outflow of blood from S. is carried out by page of the fourth ventricle on several veins falling into a basal or big brain vein. From S. of the page located in the field of a lateral pocket blood flows on veins of a lateral pocket of the fourth ventricle (w. recessus lateralis ventriculi quarti) in srednemozgovy veins (vv. mesencephalicae).
The vascular basis of the third ventricle represents itself the lamina located under the arch of a brain between the right and left thalamus (see), to-ruyu it is possible to see after removal of a corpus collosum and the arch of a brain. Its form depends on a form and the sizes of the third ventricle. In a vascular basis of this ventricle allocate 3 departments: average, concluded between brain strips of a thalamus, and two side, the covering upper surfaces of a thalamus; besides, distinguish the right and left edges, top and bottom leaves. Upper closes a triangular crack between legs of the arch of a brain, lower — prilezhit to an ependyma of the third ventricle. Together with an ependyma the vascular basis makes a roof of the third ventricle. Behind leaves of a vascular basis disperse. Upper extends to a corpus collosum, the arch and further to cerebral hemispheres where represents a soft cover of a brain; lower covers upper surfaces of a thalamus. From the lower leaf on each side from the centerline vorsina, segments, nodes C. of page of the third ventricle are implemented into a cavity of the third ventricle. In front the texture approaches interventricular foramens, through to-rye the page of side ventricles connects to S.
In S. of page of the third ventricle medial and lateral back fleecy branches branch (of choroidei posteriores med. et lat.) back brain artery (. cerebri post.) and fleecy branches (rr. choroidei ventriculi tertii) front fleecy artery (. choroidea ant.). Medial back fleecy branches (1 — 3) depart usually from a post-communication part of a back brain artery. One branch with a diameter of 0,4 — 0,8 mm meets more often. It follows medialny to a back brain artery, surrounds a leg of a brain, approaches under the roller of a corpus collosum and branches in a vascular basis of the third ventricle, taking part in S.'s formation by the village. Through interventricular foramens this branch anastomoses with a lateral back fleecy branch. The lateral back fleecy branch (1 — 3) branches off usually from back brain less often from an upper cerebellar artery (a. cerebelli sup.) and, being located along a pillow of a thalamus, extends in a vascular basis of side ventricles. One trunk of a branch meets more often, to-ry in the field of interventricular foramens sends branches to a vascular basis of the third ventricle. The fleecy branches of the third ventricle originating from a front fleecy artery anastomose with back fleecy branches of a back brain artery. Outflow of blood from S.'s veins of page of the third ventricle is carried out by several (3 — 5) thin veins relating to back group of inflows of internal brain veins (vv. cerebri int.).
The village of the village of side ventricles (plexus choroidei ventriculorum lateralium) is S.'s continuation by the village of the third ventricle, a cut is stuck out in side ventricles from the medial parties, through cracks between thalamuses and the arch. From a cavity of each ventricle of S. of page it is covered with a layer of an epithelium (lamina choroidea epithelialis), to-ry it is attached on the one hand to the arch, and with another — to the attached plate of a thalamus (lamina affixa). After S.'s separation of page on the edge of the arch there are a tape of the arch (tenia fornicis) and a small fringe of a hippocampus (fimbria hippocampi), and on the attached plate — a vascular tape (tenia choroidea), edges is located over a thalamus and lasts from an interventricular foramen until the end of the lower horn. The village of the village of each side ventricle is placed in its central part and passes into the lower (temporal) horn. The village of the village forms a front fleecy artery, partially branches of a medial back fleecy branch. The front fleecy artery usually is a branch of an internal carotid artery (see), but can begin from average brain or back connecting arteries. On the way to a side ventricle it gives branches to basal kernels. Veins S. of page of a side ventricle form numerous gyrose channels. Between vorsina of fabric of textures there is a large number of the veins tied between themselves an anastomosis. Many veins which are especially turned into a cavity of a ventricle have sinusoidal expansions, form loops and half rings. S.'s arteries of page are braided by venous vessels. Outflow of blood of page of a side ventricle comes from S. in top and bottom fleecy veins (vv. choroideae sup. et inf.). The upper fleecy vein forms from S.'s veins of page in the lower (temporal) horn and the central part of a side ventricle. It falls more often into a talamostriarny vein, is more rare in internal brain; forms an anastomosis with the lower fleecy vein. Sometimes instead of a trunk of an upper fleecy vein there are numerous small veins falling directly into an internal brain vein. The lower fleecy vein forms in the central part of a side ventricle, passes, receiving inflows, through S. the page in the lower horn and falls into a basal vein.
A vascular basis and S. of page the periarterial neuroplexes of century of N of page extending to fleecy arteries and branches from internal sleepy and the main innervate (basilar, T.) arteries. At the same time sources of sympathetic fibers are upper cervical and star-shaped nodes of a sympathetic trunk, and parasympathetic (see the Autonomic nervous system) — a vagus nerve (see). The sensitive innervation is carried out by the branches of a trifacial (see) forming in a vascular basis and in vessels of textures sensitive nerve terminations.
The vascular texture is covered with a single-layer cubic epithelium — vascular epen-dimotsita (ependymocyti choroidei). At fruits and newborns vascular ependimotsita have the cilia surrounded with microvillis. According to Scott (D. E. Scott) et al. (1974), at adults on an apical surface of cells of an eyelash remain. By data the Tour-repair and to Atya (J. Turchini, V. Ates, 1975), cilia of ependimotsit at fruits have the central tubules, quantity to-rykh in an eyelash can reach four. Vascular ependimotsita are connected by the continuous locking zone (zonula occludens). Near the basis of a cell there is a round or oval kernel. Cytoplasm of cells of a zernist in a basal part, contains many large mitochondrions and pinotsitoz-ny bubbles, lysosomes and other organellas. On the basal party of vascular ependimotsit folds form. Epithelial cells are located on the connecting layer consisting of collagenic and elastic fibers, connective tissue cells. Under a connective tissue layer there is actually S. of page. S.'s arteries of page form kapillyaropodobny vessels with a wide gleam and the wall characteristic of capillaries (fig. 2). Pages have outgrowths, or fibers, S. in the middle the central vessel, a wall to-rogo consists of an endothelium; the vessel is surrounded with connective tissue fibers; the fiber is outside covered with vascular ependimotsi-ta. According to Milorat (T. Mi-lhorat, 1976), a barrier between blood C. of page and cerebrospinal liquid consists of system of the circular hard connections connecting adjacent epithelial cells, heterolytic system of pi-notsitozny bubbles and lysosomes of cytoplasm of ependimotsit and system of the cellular enzymes connected with active transport of substances in both directions between plasma and cerebrospinal liquid.
At newborns and children of early age the epithelial cover of S. of page is developed considerably, in the subsequent; becomes thinner. Due to the general growth of a brain and S. of page blood vessels in them coil, and textures become fleecy. Fibers are especially well-marked at young age. In old age the quantity of fibers and their sizes decrease. The person is more senior, especially tortuosity of textures of veins, including and small is expressed, the venous loops and phlebectasias are formed more.
Basic similarity of ultrastructure of S. of page to such epithelial educations as renal balls suggests that function C. of page is connected with products and transport of cerebrospinal liquid (see). Veyndl and Dzhoynt (A. Weindl, R. J. Joynt, 1972) call S. page okolozheludochkovy body. In addition to secretory function C. of page, the regulation of composition of cerebrospinal liquid which is carried out by the soaking-up mechanisms of ependimotsit is important. By means of phase-contrast microcinematography it is revealed that various particles getting on an epithelial vystilka of S. of page move cilia and microvillis to openings of ventricles. The movements of cilia create the current of cerebrospinal liquid promoting removal of a cellular detritis from a surface of a vascular texture.
S.'s Pathology of page is most often secondary and caused by their defeat at meningitis, tuberculosis, hydrocephaly, sypny and a typhoid, scarlet fever, measles, diphtheria, etc. Actually S.'s pathology of page can be connected with development of tumors, coming from elements of their fabric.
Most often S. of page are surprised at an acute lymphocytic choriomeningitis (see the Choriomeningitis lymphocytic). At the same time the expressed lymphocytic infiltration of fabric C. of page of the third and fourth cerebral cavities, considerable accumulation of cerebrospinal liquid in cerebral cavities and in a subarachnoid space is noted. Treatment is directed to a basic disease.
At tubercular meningitis (see) vascular textures are surprised, according to P. P. Erofeyev (1947), in 73,68%, and according to Kment — in 82%. Extensive perivascular infiltrates of preferential lymphoid character, desquamation and sharp dystrophy of an epithelial cover of fibers, changes of vascular walls are noted up to a fibrinous necrosis, and sometimes tubercular granulomas. At hron. tubercular meningitis the phenomena of sharply expressed choroiditis with formation of a set of tubercles are observed. Process can come to the end with development of a gliosis (see).
At hydrocephaly (see) at the beginning of its development in S. pages occur a lump - pensatorno-adaptive changes — the number of fibers decreases, there comes dystrophy of cells of an epithelium, the vascular network is reconstructed. Further gradually the atrophy of vascular textures develops, they decrease, become thinner, flattened, deformed, quite often turning into scarcely noticeable strips. At gistol. a research define defeat of fibers, quite often death of an epithelium, fibrosis of a connective tissue basis, a sclerosis of blood vessels.
At atherosclerosis (see) in S.'s arteries of page deposits of lipoid, fibrous thickenings and a hyperplasia of an internal cover meet. In the large arterial trunks feeding S. with page there can also be atherosclerotic changes expressed in various degree. At an idiopathic hypertensia (see) in S. villages find the phenomena of plasmatic treatment and a hyalinosis of arterioles, and in large arteries — a thickening of walls and a hyperplasia of an elastic membrane.
At a diabetes mellitus (see a diabetes mellitus) in cellular elements C. of page the increased maintenance of a glycogen is noted, at some other diseases — inclusions of iron, silver. At impact of ionizing radiation and intoxication find sclerous changes of a stroma of S. of page, increase in lipidic inclusions and vacuoles in cytoplasm of cells of an epithelium and accumulation of lipids in the main interstitial substance. At leukoses (see) in S.'s stroma of page define the centers of an extramedullary hemopoiesis (see).
S.'s tumors of page meet very seldom. They make, by data A. L. Polenov and I. S. Bab-chin, apprx. 0,3 — 0,6% of all new growths of a brain at adults and, according to G. P. Kornyansky — to 2% at children. Tumors more often in the fourth are localized or side ventricles, is more rare in the third ventricle. Distinguish a benign tumor — horioid papilloma (see) and malignant — a horioid-carcinoma. Meningososudisty or mesenchymal tumors, coming from stromas of S. of page are much less often observed. Among them distinguish high-quality — a meningioma (see), fibroma (see), an angioma (see) — and malignant — sarcoma (see). Even less often dermoid cysts (see the Dermoid) and metastatic cancer of S. of page meet.
The basic in a wedge, a picture at S.'s tumors of page irrespective of them lo-. kalization the occlusal syndrome is (see). Absence defined nevrol is characteristic of S.'s tumor of page of a side ventricle. symptom complex. The course of a disease the remittiruyushchy, caused by periodic obstruction by a tumor Monroe openings (a median aperture of the IV ventricle, T.). Thereof asymmetric hydrocephaly develops, and children of early age have an asymmetric shape of a skull.
At S.'s tumor of page of the third ventricle vegetative frustration, obesity and an amenorrhea at women (see the Amenorrhea), drowsiness, a hyperthermia (see Gipertermiches-ky a syndrome), a polydipsia (see), epileptic seizures of diencephalic type are noted (see. A hypothalamic syndrome) and special gipertenzionny attacks like a cerebrate rigidity (see). The prematurity of a syndrome of occlusal hydrocephaly with focal symptoms from a bottom of the fourth ventricle and a worm of a cerebellum is characteristic of S.'s tumor of page of the fourth ventricle (see). The most typical symptoms are vomiting, forced position of the head.
The diagnosis of the tumor located in a cavity of the fourth ventricle put on the basis a wedge, yielded and results of additional researches. At S.'s tumors of page of side and third ventricles in diagnosis X-ray contrast methods of a research — a ventrikulografiya (see), an angiography (see), a computer tomography (see the Tomography computer), a gamma encephalography (see the Encephalography) and a ventrikuloskopiya have crucial importance (see). Among the listed methods preference is given to a computer tomography as the most informative and sparing method of a research.
Treatment operational. At malignant tumors after operation apply radiation therapy (see). At impossibility of an oncotomy from a cavity of the third or fourth ventricle make palliative operations for removal of an occlusal syndrome. The forecast is defined by the nature of a tumor and radicalism of its removal.
See also Brain .
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C.C. Mikhaylov; V. I. Rostotskaya (pathology).