Retinal pigment cells are involved in. Detachment of the retinal pigment epithelium. Treatment of pigmentary dystrophy

2.Layer of rods and cones

3. Outer boundary plate

4. Outer nuclear layer

5. Outer plexiform layer

6. Inner nuclear layer

7. Inner plexiform layer

8. Ganglion cell layer

9. Nerve fiber layer

10. Internal boundary membrane

The structure of the pigment epithelium

a) Finally, behind the layer of rods and cones is, as we know, a layer pigmented epithelium(1) the retina (or the pigment layer of the retina) located on the basement membrane.

b) Pigment epithelial cells have

processes covering the outer segments of rods and cones

(3-7 processes around each rod and up to 30-40 around the cone).

c) The pigment in cells is contained in melanosomes.

Functions pigmented epithelium:

absorption of excess light (as already noted in Section 16.2.1.2.III),

supply of photoreceptor cells with retinol (vitamin A), which is involved in the formation of light-sensitive proteins - rhodopsin and iodopsin,

phagocytosis spent components of rods and cones (p. 16.2.5.5)

The innervation of the striated muscles, smooth and glands is disturbed.

Option 4

1) Sensory nerve nodes are located along the dorsal roots of the spinal cord and cranial nerves. The source of origin is nerve fibers. In the spinal ganglia, pseudo-unipolar neurons are located, which are characterized by a spherical body, a light nucleus, they secrete large and small cells, according to the conduction of impulses. 2) The posterior horns contain several nuclei formed by multipolar intercalary neurons on which the axons of the pseudo-unipolar cells of the spinal ganglia end, which carry information from the receptors. Axons of intercalary neurons: end in the gray matter of the spinal cord, form intersegmental connections in the gray matter of the spinal cord, exit into the white matter of the spinal cord while forming outgoing and descending pathways, some of them pass to the opposite side of the spinal cord.

The intermediate zone of the gray matter of the spinal cord is located between the anterior and posterior horns. Here, from the 8th cervical to the 2nd lumbar segment, there is a protrusion of the gray matter - the lateral horn. In the medial part of the base of the lateral horn, a difficult nucleus, well delineated by a layer of white matter, consisting of large nerve cells, is noticeable. This nucleus stretches along the entire posterior column of gray matter in the form of a cellular cord (Clarke nucleus). The largest diameter of this nucleus is at the level from 11 thoracic to 1 lumbar segment. In the lateral horns, there are the centers of the sympathetic part of the autonomic nervous system in the form of several groups of small nerve cells combined into a lateral intermediate (gray) substance. The axons of these cells pass through the anterior horn and exit the spinal cord as part of the anterior roots. In the intermediate zone, the central intermediate (gray) substance is located, the processes of cells of which are involved in the formation of the spinocerebellar pathway. At the level of the cervical segments of the spinal cord between the anterior and posterior horns, and at the level of the upper thoracic segments - between the lateral and posterior horns in the white matter adjacent to the gray, the reticular formation is located. The reticular formation here has the form of thin bars of gray matter, intersecting in different directions, and consists of nerve cells with a large number of processes.

3) Functional apparatuses of the eyeball a) Refractive (cornea, aqueous humor, lens, stele body) b) Accommodation (iris, ciliary body) c) Receptor (retina) The lens is a biconvex body, held by the fibers of the ciliary band, consists of a capsule of the lens a transparent layer covering the lens from the outside, the epithelium of the lens is a layer of cubic cells, lens fibers are epithelial cells of a hexagonal shape lying parallel to the surface of the lens. With the defeat of the anterior roots, paresis and atrophy of the cervical muscles occur,

The innervation of the transversely striated, smooth muscle tissue and glands is disturbed.

Option 5

1) Since the spinal ganglion has a fusiform shape and is covered with a capsule of dense fibrous connective tissue, the accumulation of bodies of pseudo-unipolar neurons is located along its periphery. From the body of the pseudo-unipolar neuron, a process dividing in a T-shaped manner departs, into 2 afferent and efferent branches. The afferent ends at the peripheral receptors. The afferent one enters into the composition of the posterior root in the spinal cord. 2) The granular layer of the cerebellum contains the bodies of grain cells, large grain cells, cerebellar glomeruli-synaptic contact zones, between mossy fibers, dendrites of grain cells. Grain cells - small neurons with poorly developed organelles and short dendrites - axons are directed to the molecular layer, where they divide into 2 branches in a T-shape, forming excitatory synapses on the dendrites of the cells. Large grain cells - contain well-developed organelles. The axons form synapses in the dendrites of the grain cells, while the long ones rise into the molecular layer. There are large stellate neurons of types 1 and 2. In the overwhelming majority, type 1 Golgi cells, the dendrites of which are directed to the molecular layer, forming synapses with axons. Golgi cells of type 2, their dendrites are not numerous, they strongly branch and form contacts with collateral axons of piriform neurons. 3) The lower wall of the membranous canal of the cochlea is the basilar plate, which forms the bottom of the canal, from the side of the tympanic ladder is lined with a single-layer squamous epithelium. It consists of an amorphous substance in which collagen fibers are located, forming 20 thousand auditory strings stretched from the spiral ligament to the spiral bone plate. The strings perceive sound in a range of 16-20 thousand hertz. The spiral organ is formed by sensory-epithelial receptor cells and supporting cells. Sensory epithelial cells are divided into 2 types: internal hair cells (pear-shaped are located in 1 row and surrounded by internal phalangeal cells), external hair cells (prismatic forms lie in the cup-shaped impressions of the outer phalangeal cells). The supporting cells are subdivided into (Column cells, phalanx cells) borderline, external support, Bettcher cells)

TASK - The occipital lobes of the brain determine the capabilities of the human visual system. Damage to this area can lead to partial loss of vision or even complete blindness. Bark type - granular

Option 6

1) Peripheral nerves consist of bundles of myelinated and nonmyelinated nerve fibers, single neurons or their clusters and sheaths. The bodies of neurons are found in the gray matter of the spinal cord and brain and spinal nodes (ganglia). The nerves contain sensory (afferent) and motor (efferent) nerve fibers, but more often both. Endoneurium is located between the nerve fibers, represented by delicate layers of loose fibrous connective tissue with blood vessels. 2) The intermediate zone of the gray matter of the spinal cord is located between the anterior and posterior horns. Here, from the 8th cervical to the 2nd lumbar segment, there is a protrusion of the gray matter - the lateral horn. In the medial part of the base of the lateral horn, a difficult nucleus, well delineated by a layer of white matter, consisting of large nerve cells, is noticeable. This nucleus stretches along the entire posterior column of gray matter in the form of a cellular cord (Clarke nucleus). The largest diameter of this nucleus is at the level from 11 thoracic to 1 lumbar segment. In the lateral horns, there are the centers of the sympathetic part of the autonomic nervous system in the form of several groups of small nerve cells combined into a lateral intermediate (gray) substance. The axons of these cells pass through the anterior horn and exit the spinal cord as part of the anterior roots. In the intermediate zone, the central intermediate (gray) substance is located, the processes of cells of which are involved in the formation of the spinocerebellar pathway. At the level of the cervical segments of the spinal cord between the anterior and posterior horns, and at the level of the upper thoracic segments - between the lateral and posterior horns in the white matter adjacent to the gray, the reticular formation is located. The reticular formation here has the form of thin bars of gray matter, intersecting in different directions, and consists of nerve cells with a large number of processes. 3) The peripheral part of the vestibular analyzer, located in the bony labyrinth of the inner ear, (represented by the sac, the uterus and the ampullae of the semicircular canals) The total number of hair cells is 16-17 thousand. Stereocilia and kinocilia are immersed in a layer of gelatinous substance without otoliths. Functions - Ampullary scallops perceive angular accelerations.

4) With the pathology of the spiral ganglion, an electrical potential will be perceived, which is transmitted at the end of the bipolar cells of the spiral ganglion (their axons form the cochlear nerve), which leads to hearing impairment.

Option-7 1) 1… .. SPINAL NODES (SPINAL GANGLES) - are laid in the embryonic period from the ganglion plate (neurocytes and glial elements) and mesenchyme (microgliocytes, capsule and SDT interlayer). Spinal nodes (SMU) are located along the dorsal roots of the spinal cord. Outside, they are covered with a SDT capsule, from the capsule inwardly there are interlayers-septa of loose SDT with blood vessels. The bodies of neurocytes are located under the capsule in groups. SMU neurocytes are large, body diameter up to 120 microns. The nuclei of neurocytes are large, with distinct nucleoli, located in the center of the cell; euchromatin predominates in the nuclei. The bodies of neurocytes are surrounded by satellite cells or mantle cells - a type of oligodendrogliocytes. The SMU neurocytes are pseudo-unipolar in structure - the axon and dendrite depart from the cell body together as one process, then diverge in a T-shape. The dendrite goes to the periphery and forms in the skin, in the thickness of the tendons and muscles, in the internal organs, sensitive receptor endings that perceive pain, temperature, tactile stimuli, i.e. SMU neurocytes are sensitive in function. Axons along the dorsal root enter the spinal cord and transmit impulses to the associative neurocytes of the spinal cord. In the central part of the SMU, nerve fibers covered with lemmocytes are located parallel to each other. 2) …… Purkinje cells-form the middle ganglionic layer of the cerebellum. The cell bodies are pear-shaped, located approximately at the same distance from each other, forming a row in one layer. 2-3 dendrites depart from the neuron body into the molecular layer, which intensively branch and occupy the entire thickness of the molecular layer. The terminal branches of the dendrites end with spines. The spine is a collateral of the dendrite to provide contacts. The spine has a thin "stem" that ends with a "button". On all dendrites of one Purkinje cell there are more than 90 thousand spines. Dendrites form contacts with their spines with climbing fibers, axons of grain cells of the inner layer, axons of stellate neurons of the molecular layer. An axon departs from the lower pole of the piriform neuron, which, having passed the granular layer of the cortex, enters the white matter of the cerebellum and goes to the nuclei of the cerebellum, where it forms synapses. collateral departs from the axon of the Purkinje cell, which returns to the ganglionic layer and braids the body of the neighboring Purkinje cell, in the form of a basket, forming synapses. Part of the collaterals reaches the molecular layer, where they contact the bodies of the basket neurons. 3) The retinal neuroglia are represented by radial gliocytes (Müllerian cells), astrocytes and microglia. Radial gliocytes (Müller cells) are large process cells that extend almost the entire thickness of the retina perpendicular to its layers. occupy almost all the spaces between neurons and their processes. Their bases form the inner glial border membrane, which limits the retina from the vitreous body, and by the apical sections, due to the processes, the outer glial border membrane. They also surround the capillaries, forming the blood-retinal barrier together with astrocytes. Astrocytes-glial cells are located mainly in the inner layers of the retina and capillaries covering their processes (form the hemato-retinal barrier). Microglial cells are located in all layers of the retina and are few in number. They perform a phagocytic function. TASK - The occipital lobes of the brain determine the capabilities of the human visual system. Damage to this area can lead to partial loss of vision or even complete blindness. Bark type - granular

Option 8

1) In the spinal cord, gray and white matter are distinguished. On the transverse section of the spinal cord, the gray matter looks like the letter H. Anterior (ventral), lateral, or lateral (lower cervical, thoracic, two lumbar) and posterior (dorsal) horns of the gray matter of the spinal cord are distinguished. The gray matter is represented by the bodies of neurons and their processes, nerve endings with a synaptic apparatus, macro- and microglia and vessels. White matter surrounds the outside of the gray matter and is formed by bundles of pulpy nerve fibers that form pathways throughout the spinal cord. These pathways are directed towards the brain or descend from it. This also includes fibers heading to the higher or lower segments of the spinal cord. In addition, astrocytes, individual neurons, and hemocapillaries are found in the white matter. In the white matter of each half of the spinal cord (on a transverse section), three pairs of pillars (cords) are distinguished: posterior (between the posterior median septum and the medial surface of the posterior horn), lateral (between the anterior and posterior horns) and anterior (between the medial surface of the anterior horn and anterior median fissure). In the center of the spinal cord, there is a canal lined with ependymocytes, among which there are poorly differentiated forms that, according to some authors, are capable of migration and differentiation into neurons. In the lower segments of the spinal cord (lumbar and sacral), after puberty, gliocytes proliferate and the canal is overgrown, and an intraspinal organ is formed. The latter contains gliocytes and secretory cells that produce a vasoactive neuropeptide. The organ undergoes involution after 36 years. The neurons of the gray matter of the spinal cord are multipolar. Among them, there are neurons with a few weakly branching dendrites, neurons with branching dendrites, as well as transitional forms. Depending on where the processes of neurons go, there are: internal neurons, the processes of which end in synapses within the spinal cord; bundle neurons, the neurite of which goes as part of bundles (pathways) to other parts of the spinal cord or to the brain; root neurons, the axons of which leave the spinal cord as part of the anterior roots. 2) The agranular type of the cortex is characteristic of its motor centers and is distinguished by the greatest development of the III, V, VI layers of the cortex with a weak development of II and IV (granular) layers. Such areas of the cortex serve as sources of the descending pathways of the central nervous system. The granular type of the cortex is characteristic of the areas where the sensitive cortical centers are located. It is distinguished by a weak development of layers containing pyramidal cells, with a significant manifestation of granular layers. 3) The olfactory organ is a chemoreceptor. He perceives the action of molecules of odorous substances. This is the most ancient type of reception. As part of the olfactory analyzer, three parts are distinguished: the olfactory region of the nasal cavity (peripheral part), the olfactory bulb (intermediate part), as well as the olfactory centers in the cerebral cortex. Development of the sense of smell. The source of formation of all parts of the olfactory organ is the neural tube, symmetrical local thickenings of the ectoderm - olfactory placodes, located in the anterior part of the head of the embryo and mesenchyme. The placode material invades the underlying mesenchyme, forming olfactory sacs connected to the external environment through openings (future nostrils). The wall of the olfactory sac contains stem cells, which at the 4th month of embryogenesis by divergent differentiation develop into neurosensory (olfactory) cells that support and basal epithelial cells. Part of the cells of the olfactory sac is used to build the olfactory (Bowman's) gland. At the base of the nasal septum, a vomeronasal (Jacobson) organ is formed, the neurosensory cells of which respond to pheromones. The structure of the sense of smell. The olfactory lining of the peripheral part of the olfactory analyzer is located on the upper and partially middle conchas of the nasal cavity. Its total area is about 10 cm2. The olfactory region has an epithelium-like structure. The receptor part of the olfactory analyzer is delimited from the underlying connective tissue by the basement membrane. Olfactory neurosensory cells are spindle-shaped with two processes. In shape, they are divided into rod-shaped and cone-shaped. The total number of olfactory cells in humans reaches 400 million, with a significant predominance of the number of rod-shaped cells. The peripheral process of the olfactory neurosensory cell, 15-20 µm in length, has a thickening at the end, called the olfactory club. On the rounded apex of the olfactory clubs there are 10-12 olfactory hairs - antennae. Their length reaches 2-3 microns. Antennas have an ultrastructure characteristic of cilia, i.e., they contain 9 peripheral and 2 central paired protofibrils extending from typical basal bodies. The antennas perform continuous automatic pendulum-type movements. The top of the antennas moves along a complex trajectory, due to which the possibility of their contact with the molecules of odorous substances increases. At the same time, the antennae are immersed in a liquid medium, which is the secret of the tubular-alveolar olfactory glands (Bowman's). They are characterized by a merocrine type of secretion. The secretion of these glands moisturizes the surface of the olfactory lining. The central process of the olfactory neurosensory cell, the axon, goes to the intermediate part of the olfactory organ, the olfactory bulb, and establishes a synaptic connection there in the form of a glomerulus with mitral neurons. In the olfactory bulb, the following layers are distinguished: 1) a layer of olfactory glomeruli, 2) an outer granular layer, 3) a molecular layer, 4) a layer of mitral cells, 5) an inner granular layer, 6) a layer of centrifugal fibers. The central part of the olfactory organ is localized in the hippocampus and in the hippocampal gyrus of the cerebral cortex, where the axons of mitral cells are directed and form synaptic connections with neurons. Thus, the olfactory organ (the olfactory region of the nasal cavity and the olfactory bulb), like the organ of vision, has a layered arrangement of neurons, which is characteristic of screen nerve centers. The supporting epithelial cells of the olfactory region are highly prismatic cells with microvilli, arranged in the form of a multi-row epithelial layer, providing the spatial organization of neurosensory cells. Some of these cells are secretory and also have phagocytic capacity. Basal epithelial cells of a cubic shape are poorly differentiated (cambial) and serve as a source for the formation of new cells of the olfactory lining.

The posterior horns contain several nuclei formed by small and medium-sized multipolar intercalary neurons, on which the axons of the pre-unipolar cells of the spinal ganglia end. The axons of the intercalary neurons end in the gray matter of the spinal cord on the motor neurons lying in the anterior horns; form intersegmental connections within the gray matter of the spinal cord; exit into the white matter of the spinal cord, where they form ascending and descending wire paths. In case of damage, the transport of these conducting paths is disrupted.

Option-9

1) The intermediate zone of the gray matter of the spinal cord is located between the anterior and posterior horns. Here, from the 8th cervical to the 2nd lumbar segment, there is a protrusion of the gray matter - the lateral horn. In the medial part of the base of the lateral horn, a difficult nucleus, well delineated by a layer of white matter, consisting of large nerve cells, is noticeable. This nucleus stretches along the entire posterior column of gray matter in the form of a cellular cord (Clarke nucleus). The largest diameter of this nucleus is at the level from 11 thoracic to 1 lumbar segment. In the lateral horns, there are the centers of the sympathetic part of the autonomic nervous system in the form of several groups of small nerve cells combined into a lateral intermediate (gray) substance. The axons of these cells pass through the anterior horn and exit the spinal cord as part of the anterior roots. In the intermediate zone, the central intermediate (gray) substance is located, the processes of cells of which are involved in the formation of the spinocerebellar pathway. At the level of the cervical segments of the spinal cord between the anterior and posterior horns, and at the level of the upper thoracic segments - between the lateral and posterior horns in the white matter adjacent to the gray, the reticular formation is located. The reticular formation here has the form of thin bars of gray matter, intersecting in different directions, and consists of nerve cells with a large number of processes. 2) large, giant neurons, formed by large, and in the area of ​​the anterior central gyrus, giant pyramidal neurons. The apical dendrites reach the molecular layer, while the lateral ones extend within their layer, forming numerous synapses. The axons of these cells form pyramidal pathways (tracts) reaching the nuclei of the brainstem and the motor nuclei of the spinal cord.

3) The organ of taste is the peripheral part of the taste analyzer and is located in the oral cavity. Taste receptors are composed of neuroepithelial cells, contain branches of the taste nerve and are called taste buds. Taste bulbs are oval in shape and are located mainly in the leaf-shaped, mushroom-shaped and grooved papillae of the mucous membrane of the tongue (see the section "Digestive system"). They are found in small quantities in the mucous membrane of the anterior surface of the soft palate, epiglottis and posterior pharyngeal wall. Irritations perceived by the bulbs go to the nuclei of the brain stem, and then to the area of ​​the cortical end of the taste analyzer. Receptors are able to distinguish four basic tastes: sweet receptors are perceived at the tip of the tongue, bitter - receptors located at the root of the tongue, salty and sour - receptors at the edges of the tongue.

TASK-......

The ampullary combs perceive angular accelerations: when the body rotates, an endolymph current arises, which deflects the dome, which stimulates the hair cells due to bending of the stereocilia. The movement of the dome towards the kinocilium causes excitation of the receptors, and in the opposite direction, their inhibition. Accordingly, with a pathological process, all these processes will be disrupted.

Option 10

1) the anterior horns contain multipolar motor cells (motoneurons), a total of 2-3 million. Motor neurons are united into nuclei, each of which stretches for several segments. I distinguish large alpha mononeurons and smaller gamma motor neurons scattered among them.

On the processes and bodies of motoneurons there are numerous synapses that exert excitatory and inhibitory effects on us.

A) collaterals of axons of pseudo-unipolar cells of spiral nodes, forming two-neuronal arcs with them

B) axons of intercalary neurons

C) axons of Renshaw cells

D) Downstream Fibers

2) Purkinje cells-form the middle ganglionic layer of the cerebellum. The cell bodies are pear-shaped, located approximately at the same distance from each other, forming a row in one layer. From the neuron body go into the molecular layer 2-3 dendrites, which intensively branch and occupy the entire the thickness of the molecular layer. The terminal branches of the dendrites end with spines. The spine is a collateral of the dendrite to ensure contacts. The spine has a thin "stem" that ends with a "button". All dendrites of one Purkinje cell have over 90 thousand spines. The dendrites, with their spines, form contacts with climbing fibers, axons of grain cells of the inner layer, axons of stellate neurons of the molecular layer. An axon departs from the lower pole of the piriform neuron, which, after passing the granular layer of the cortex, enters the white matter of the cerebellum and goes to the nuclei of the cerebellum, where it forms synapses. Within the granular layer from the axon the Purkinje cell leaves the collateral, which returns to the ganglionic layer and about weaves the body of the neighboring Purkinje cell, in the form of a basket, forming synapses. Part of the collaterals reaches the molecular layer, where they contact the bodies of the basket neurons.

3) The peripheral part of the auditory analyzer is located in front of the labyrinth of the inner ear, namely in the cochlea - a spiraling canal that makes two and a half turns. A spiral plate extends from the central bone shaft of the cochlea along its entire length, protruding into the canal. Between the plate and the outer wall of the canal, the main membrane is stretched, consisting of the finest elastic connective tissue fibers. On the upper side of the main plate is the receptor apparatus of the auditory analyzer - a spiral organ.

Disrupt the function of the descending and ascending paths

Option 11

1 …… The nervous system unites parts of the body into a single whole, ensures the regulation of various processes, coordinates the functions of various organs and tissues, ensures the interaction of the body with the external environment. It perceives a variety of information coming from the external environment and internal organs, processes it and generates signals , providing reciprocal reactions. Anatomically, the nervous system is conventionally divided into –central, which includes the brain and spinal cord and peripheral nerve nodes (ganglia), nerve trunks, nerve endings. Physiologically, the nervous system is divided into –somatic (animal), which regulates the functions of voluntary movement , and autonomic (autonomic), which regulates the activity of internal organs, vessels, glands. In the nervous system, centers, conductors, terminal apparatuses are distinguished. Centers are called clusters of neurons in which synaptic connections between neurons are carried out. By structure and function, they are nervous e centers of the nuclear type are random clusters of neurons, on the dendrites and bodies of which there are synaptic connections with the axons of other neurons. These centers are phylogenetically the most ancient and are located in the spinal cord and some other parts of the brain. Nerve centers of the screen type, in which neurons are located strictly regularly, in the form of layers similar to screens on which nerve impulses are projected. These centers of a later origin, form the surface layer of the cerebral hemispheres of the brain and cerebellum, the so-called cortex 2 ... ..B In the molecular layer, there are two types of neurons: basket and two types of stellate (large and small). Basket neurons are located closer to the middle layer, their body size is from 8 to 20 microns. Numerous dendrites branch in their layer and form synapses with axons of grain cells of the inner A long axon departs from the body of the neuron, which runs parallel to the ganglionic layer above the bodies of piriform neurons. Passing the piriform cell from the axon of the basket neuron, a collateral departs, which goes to the body of the piriform neuron and braids it like a basket, forming numerous baskets. Axon of one basket cell supplies collaterals about 70 pear-shaped neurons. Large stellate neurons have long and highly branched dendrites and axons, which form synapses with axons of grain cells in the inner cortex and with climbing fibers. Axons are in contact with the dendrites of piriform neurons, and many axons reach the bodies of piriform neurons, braid them in the form of a basket, forming numerous synapses. Small stellate neurons have short dendrites and axons. Dendrites form synapses with axons of grain cells of the inner layer of the cortex and with climbing fibers. Axons are in contact with dendrites of piriform neurons. Cells of the molecular layer are intercalated, and functionally are inhibitory, i.e. cause inhibition of piriform neurons. 3 ... ..1) pigment epithelium. 2) A layer of rods and cones. 3) Outer glial border membrane. 4) Outer nuclear 5) Outer reticular 6) Inner nuclear 7) Inner reticular 8) Ganglion 9) layer formed by the axons of opticogangionic neurons. 10) Internal border glial membrane. Pigment epithelium - directly connected with the basement membrane of the choroid and less firmly with the adjacent layers of the retina. This feature causes the possibility of retinal detachment from the pigment epithelium in pathology, which leads to the death of the votosensory layer, which receives nourishment diffusely through the pigment layer. On the periphery of the retina, the pigment epithelium formed by cubic and cells, and in the center of the retina - prismatic hexagonal cells. The cytoplasm has a well-developed synthetic apparatus, many mitochondria. The apical ends of pigmentocytes have long processes that penetrate the photosensory layer and surround the outer segments of photoreceptor cells. One segment of the rod is surrounded by 3- 7 by the processes of these cells. In the cytoplasm of pigmentocytes there are melanosomes containing the pigment melanin, which migrates in the light to the processes, in the dark to the body of the pigmentocyte. Functions-1) Shields the outer segments of photoreceptors, which prevents light scattering. 2) Absorbs up to 90 percent. Light entering the eye, which increases the resolution of the retina. 3) Reduces the breakdown of the visual pigment of rhodopsin in the rods. 4) Carries out phagocytosis of the detached discs of the outer segments of the rods. 5) Deposits the aldehyde of vitamin A-retinal, for the subsequent resynthesis of the visual pigment of rhodopsin and the regeneration of the outer discs. segments of sticks. 4 …… 4 …… Impossible, since approximately on the 27th day of pregnancy, the superficial ectoderm thickens at the point of contact with the ocular vesicle, forming a lens placode. Due to the uneven growth of its constituent cells, the lens placode and the underlying neuroectoderm invaginate. As a result, the anterior wall of the optic bladder descends, as if lining the posterior wall, and a two-layer optic cup is formed from the neuroectoderm. Its layers further differentiate into the neurosensory retina (inner layer) and retinal pigment epithelium (RPE) - the outer layer. That is, in the absence of the lens placode, a bilayer goblet rudiment will not form.

Option 12

1… ..SPINAL NODES (SPINAL GANGLES) - are laid in the embryonic period from the ganglion plate (neurocytes and glial elements) and mesenchyme (microgliocytes, capsule and SDT interlayer). Spinal nodes (SMU) are located along the dorsal roots of the spinal cord. Outside, they are covered with a SDT capsule, from the capsule inwardly there are interlayers-septa of loose SDT with blood vessels. The bodies of neurocytes are located under the capsule in groups. SMU neurocytes are large, body diameter up to 120 microns. The nuclei of neurocytes are large, with distinct nucleoli, located in the center of the cell; euchromatin predominates in the nuclei. The bodies of neurocytes are surrounded by satellite cells or mantle cells - a type of oligodendrogliocytes. The SMU neurocytes are pseudo-unipolar in structure - the axon and dendrite depart from the cell body together as one process, then diverge in a T-shape. The dendrite goes to the periphery and forms in the skin, in the thickness of the tendons and muscles, in the internal organs, sensitive receptor endings that perceive pain, temperature, tactile stimuli, i.e. SMU neurocytes are sensitive in function. Axons along the dorsal root enter the spinal cord and transmit impulses to the associative neurocytes of the spinal cord. In the central part of the SMU, nerve fibers covered with lemmocytes are located parallel to each other. 2 ... .. The granular type of cortex is characterized by a strong development of the outer granular layer and the inner granular layer, they are wide with a large content of stellate neurons. The pyramidal and polymorphic layers, on the contrary, are narrow, contain few cells. In this type of cortex, afferent conductors come to an end. Therefore, the granular type of the cortex is called the sensitive (sensory) cortical centers. The stellate neurons of this layer of the cortex, when excited, are capable of causing a subjective reflection of the external world. And the agranular type has very well developed wide pyramidal, ganglionic and polymorphic salts containing pyramidal and fusiform neurons, and the outer granular and inner granular layers are narrow with a small number of neurons. This type of cortex has motor cortical centers. Such a center is the anterior central gyrus in which they are isolated two fields –4 and 6. In these fields, the cortex is built according to the agranular type. In field 4, giant pyramidal neurons (Betz cells up to 150 µm) are located in the ganglionic layer of the cortex. There are no more Betz cells in any other field of the cortex. 3… ..The peripheral part of the auditory analyzer is located along the entire length of the cochlea, which consists of a bony canal and a membranous canal in it. The organ of hearing is represented by a spiral organ adjacent to the basement membrane, which is part of the lower wall of the membranous canal. 4 …… Ampullary scallops perceive angular accelerations: when the body rotates, an endolymph current arises, which deflects the dome, which stimulates the hair cells due to bending of the stereocilia. The movement of the dome towards the kinocilium causes excitation of the receptors, and in the opposite direction, their inhibition. Accordingly, with a pathological process, all these processes will be disrupted.

Pear-shaped

Pyramidal

Ganglionic

Cones

296. The retinal pigment epithelium is part of:

Retinas

Ciliary body

Choroid

297. Retinal pigment cells are involved in:

supplying photoreceptor cells with retinol

phagocytosis of waste cell membranes

light absorption

synthesis of iodopsin

298. Choroid:

contains large arteries and veins

rich in pigment cells

contains a basal complex

forms the receptor apparatus of the eye

changes blood flow in the dark

does not contain pigment cells

299.The outer segments of photoreceptor cells contain:

pigment rhodopsin

mitochondria

membrane discs

constantly updated

basal body

300. The cornea is characterized by:

outside covered with stratified squamous non-keratinizing epithelium

outside covered with unilamellar epithelium

own substance contains glycosaminoglycans

there is a Bowman membrane

refers to the accommodative apparatus of the eye

301. The bodies of retinal neurons are located in layers:

Domestic nuclear

Rods and cones

Ganglionic

Inner mesh

Outside nuclear

302. The cornea consists of:

Cones and rods

Corneal intrinsic substance

Stratified transitional epithelium

Stratified non-keratinizing epithelium

Bowman's Membrane

Disse space

303. Cones:

color vision receptors

photons activate visual pigment in the outer segments.

there is an ellipsoid in the inner segment

outer segment contains discs

304. The cones contain:

cilia

membrane half-discs

basal body

ellipsoid

membrane discs

305. Light passes through the structures of the eye:

cornea and lens

anterior and posterior chambers of the eye

lens and blind spot

vitreous and retina

vitreous

306. Ependymal neuroglia:

Lines the canal of the spinal cord

Has eyelashes

Secrets cerebrospinal fluid

With congenital hypertrophy of the retinal pigment epithelium, we are talking about a violation of the formation of this layer during intrauterine life. The disease manifests itself with grouped pigmentation, which has an external resemblance to the track of a bear.

Until the end, the pathogenesis of retinal hypertrophy has not been studied. Some scientists believe that as a result of the formation of macromelanosomes in the pathological retina, a change in catabolic function occurs. As a result, the cells of the pigment epithelium die, and lacunas, or foci of hypogigmentation, form in their place.

Clinical manifestations of hypertrophy

With congenital hyperplasia of the retinal pigment layer, focal hyperpigmentation occurs. In their shape, the foci of hyperpigmentation resemble a bear footprint. The color of these spots can be light brown or black. The shape of the spots is round, and the edges are smooth or scalloped. Around the foci of hyperpigmentation, a rather extensive placoid area can be found. Lacunae that form in hyperplasia can be single or multiple. Grouped lesions of hyperpigmentation (small tufts or clusters) are called a bear track. The size of these clusters can be as small as a disk, and sometimes reach an entire quadrant of the fundus. No typical localization for these pathological changes has been identified. The central region of the retina, that is, the macula, is rarely involved in the pathological process.

The disease may be asymptomatic. Sometimes the foci of hyperplasia increase in size or become malignant. When performing fluorescence angiography in the early stages of pathologies, it is possible to consider the large vessels of the choroidal membrane, which intersect the lacunae. In this case, the layer of choriocapillaries is absent. Hypofluorescence can be detected throughout the hypertrophied area.

Diagnostics

Light microscopy

The layer of hypertrophied pigment epithelium is a large oval-shaped pigment granules. Photoreceptors that are adjacent to this zone undergo dystrophy (outer and inner segments). There is also a quenching of Bruch's membrane, and photoreceptors and pigment epithelial cells are absent in hypopigmentation lacunae. The choroid in this disease is not changed.

Instrumental research

During fluorescence angiography, a blockage of background choroidal fluorescence can be seen in the hyperpigmentation area. In hypopigmented lacunae, choroidal blood flow is preserved. The vascular network that covers the lesion is invisible. Sometimes there are signs of obliteration of capillaries, microaneurysms, vascular shunts, rarefaction of structures is noted, fluorescein can leak out.
When examining the visual field, relative scotomas may occur, which increase with age. EOG and ERG remain normal.

Differential diagnosis

It is necessary to distinguish congenital hypertrophy of the pigment epithelial layer of the retina from melanoma, choroidal nevus, melanocytoma. Also, differential diagnosis should be carried out with reactive hyperplasia of this layer of the retina, which occurs as a result of trauma, hemorrhage, inflammation, or the ingestion of toxic substances.

Treatment

There is no treatment for this disease.

Forecast

In the absence of pathological changes in the macular area, visual acuity decrease is not observed.

Retinal pigmentary dystrophy is a disease of a genetic nature. The process of the disease proceeds without the manifestation of obvious symptoms, but its final stages lead to a complete loss of vision.

Pigmented retinal degeneration of the eyeball is a disease resulting in a gradual narrowing of the visual fields. One of the obvious symptoms of the disease is loss of vision at twilight. The disease can be caused by a malfunction of a particular gene. In rare cases, there is a violation of the interaction of several genomes. The disease is hereditary and is transmitted through the male line. The disease may be accompanied by a malfunction of the hearing aid.

The causes of failures in the work of the genetic system of the human body have not yet been identified. Overseas researchers have found that DNA abnormalities are not one hundred percent cause of the development of pigmentary dystrophy. According to experts, the disease provokes the occurrence of disorders in the vascular system of the eyeball.

Despite the fact that the causes of the onset of the disease remain a mystery of medicine, experts have quite reliably studied the issue of its development.

Retinal pigmentosa degeneration is a rather rare condition that causes blurred vision in the dark

At the initial stage of the disease, a metabolic failure occurs in the retina of the eyeball. Also, violations affect the vascular system. As a result of the development of the disease, the retinal layer, which contains the pigment, begins to collapse. Sensitive photoreceptors, rods and cones are located in the same layer. At the first stages, degeneration processes affect only the peripheral areas of the retina. That is why the patient does not experience discomfort and painful sensations. The gradually changed area begins to increase in size until it covers the entire area of ​​the retina. When the retina is completely affected, the first serious symptoms of the disease begin to appear, a deterioration in the perception of colors and their shades.

The disease can spread to only one eye, but it is not uncommon for the disease to affect two visual organs at once. The first symptoms of the disease appear in early childhood, and by the age of twenty a person may become disabled. Severe stages of retinal pigmentary dystrophy can be accompanied by complications such as cataracts and glaucoma.

Symptoms

The sluggish development of the disease leads to the fact that most patients seek the help of specialists when pathological changes began their rapid development. The first serious symptom of the disease is difficulty navigating in low light conditions. Pathologies occurring on the peripheral part of the retina lead to narrowing of the visual fields.

Given the peculiarity of the disease, the main group of patients is children who have not reached school age. At this age, minor vision problems are not noticed, which means that parents may not know about the development of the disease.

The first stages of development can take a long time - up to five years. Subsequently, the degeneration of the peripheral region of the retina begins to progress. The visual fields at this point are strongly narrowed, in some patients there is a complete absence of lateral vision. Examination by an ophthalmologist can reveal areas with pathological changes, but if inactive, they will soon spread throughout the retina. At this stage, in some parts of the retina, gaps may appear. The vitreous humor begins to lose its transparency, becoming dull yellow. At this stage, central vision is not affected.

The exact cause of the disease has not been established, but ophthalmologists only name versions of the development of retinal pigment degeneration

The disease in an advanced stage can be complicated by the occurrence of diseases such as glaucoma and cataracts. With complications, central vision very sharply loses its acuity, and over time it can be irretrievably lost. Complications lead to the development of vitreous atrophy.

There is another form of retinal degeneration - atypical. As a result of the disease, the appearance and structure of the vascular system changes. The patient is experiencing difficulty orienting in low light conditions.

One of the rarest types of retinal degeneration is the unilateral form, and the patient will necessarily develop a cataract.

Treatment of pigmentary dystrophy

Treatment of pigment money generation of the retina of the eye, which is in the stage of development, is most often carried out with the help of medications. The actions of drugs should be aimed at normalizing blood circulation and metabolism of nutrients in the retina and the vascular system. In most cases, the following drugs are prescribed by specialists:

1. "Emoxipin". This drug corrects microcirculation in the body.
2. "Taufon"... Drops for eyes stimulate regeneration processes in the eye tissues.
3. Retinalamin. The drug prescribed for retinal dystrophy has a regenerative effect.
4. A nicotinic acid. Vitamin that stimulates the metabolism of nutrients in the body and blood circulation.
5. No-shpa with papaverine. An antispasmodic that relieves pressure in the vascular system.

These drugs can be prescribed by a doctor in the form of pills, as well as in the form of injections or eye drops.

With the development of the disease, the loss of peripheral vision is determined

Very often, in addition to medication treatment, a course of physiotherapy is prescribed to stimulate the processes of recovery and regeneration of the retina. Taking this course can activate the work of photoreceptors. Some of the popular methods today are stimulation with electrical impulses, magnetic resonance and ozone therapy. If the choroid was affected as a result of the disease, it makes sense to carry out a surgical intervention.

With the help of the operation, specialists normalize blood circulation in the reticular layer of the eyeball. To achieve this goal, it may be necessary to transplant certain tissues of the eyeball, under the perichoroidal space.

The use of vision correcting devices

Some experts recommend the treatment of retinal pigmentary degeneration with photostimulation devices. Their work is based on a technique that causes excitement in certain areas of the eyeball and slows down the process of the development of the disease.

The radiation emitted by the equipment stimulates blood circulation in the vascular system of the eyeball, and also normalizes the metabolism of nutrients. Using this technique, it is also possible to remove puffiness from the retina of the eyeball. Photostimulation of the retina of the visual organs can have a beneficial effect on strengthening the retina and improving the circulation of nutrients in the inner layers of the eyeball.

Damage begins at the periphery and spreads over several decades to the central retinal area

Forecast

Unfortunately, today medicine is still quite far from solving the issue when the disease is in a state of neglect. Very often there is news that foreign researchers have found a way to restore certain genes responsible for the onset of the disease. Already today, special implants capable of replacing the mesh are undergoing the final stage of testing.

Another approach of specialists revealed that it is possible to completely restore lost vision with the help of injections of a special substance containing cells that are sensitive to light. However, this technique is still at the stage of experiments, and it is still unknown whether scientists will be able to achieve the desired result.

Many of those who are faced with this disease know that the prognosis for the success of treatment in most cases is poor. But if the disease is detected at an early stage, using certain methods of treatment, you can stop its progression. In some cases, specialists have achieved really tangible results. People who have been diagnosed with the disease need to avoid prolonged physical exertion, as well as stress on the visual organs.

In contact with

(i.e. pigmentosum, LNH) E., whose cells contain a large number of pigment inclusions (eg, in the retina).

"pigment epithelium" in books

1. Epithelium of the skin and intestines

the author

1. Epithelium of the skin and intestines

From the book Genes and the Development of the Body the author Neifakh Alexander Alexandrovich

1. Epithelium of the skin and intestines The epithelium of the skin is multilayered, and its stem cells are located in the lower (basal) layer, which lies on the membrane that separates the epithelium from the connective tissue. Cell divisions occur in the basal layer, and some of the cells are displaced into

Ciliated epithelium

From the book Great Soviet Encyclopedia (ME) of the author TSB

Epithelium

From the book Great Soviet Encyclopedia (EP) of the author TSB

Epithelium

From the book Analyzes. Complete reference the author Ingerleib Mikhail Borisovich

Epithelium

From the book The Complete Handbook of Analyzes and Research in Medicine the author Ingerleib Mikhail Borisovich

Epithelium Epithelial cells are constantly present in urine sediment. In this case, epithelial cells originating from different parts of the genitourinary system differ in shape and structure (they secrete squamous, transitional and renal epithelium).