optic nerve belongs to the highly specialized nerves and the structure resembles the cerebral cortex.The functions of the optic nerve are in the transmission of nerve impulses, resulting in the exposure to different light stimuli from the retina to the visual center of the cerebral cortex.
Optic Nerve: Structure.
retinal nerve fibers are combined into a single optic nerve.It consists of four departments: intraocular, vnutrikanaltsevoy, intraorbital and intracranial.Intraocular department is a disc with a diameter of about 1.5 mm.The orbital portion has a length of about 3 cm. The optic nerve has a length of 5-6 mm in the bone canal and 4-17 mm in intracranial channel.
Location nerve endings in various areas of the retina is built on a specific structure.Thus, when approaching the disc, nerve fiber layer has a large thickness, while the nerve fibers in the disc are bent at right angles, thus forming an intraocular optic separated.
optic nerve starts from the disk, and is ending in the chiasm.The optic nerve in the adult has a length of 35 to 55 mm.It is covered by three meninges: hard, soft and arachnoid.The space between the shells is filled with a special liquid with complex chemical composition.
Spotting fibers from both eyes are located in the cranial cavity, which are joined in the sella.Place them together is called a chiasm.It partially overlap optic fiber.Crossings shall be those fibers that come from the inner parts of the retina.These intersections are very important for the correct diagnosis of certain diseases.After crossing formed optic tract, which at the base of his brain round the leg and end at crank bodies quadrigemina front and in the rear area of the thalamus.Geniculate body are the most important in the transmission of impulses to the visual cortex.Those fibers which terminate in the thalamus, perform reflex regulation of visceral and somatic reflexes.A front quadrigeminal bodies used to transmit reflexes pupils.Spotting fibers pass to the nuclei of the oculomotor nerve, as part of which they come into the eye, resulting in the muscles of the iris.
pathological processes of nature, which are developed in the optic nerve, have a close relationship with its structure.Due to the large amount of capillaries contained in the partitions and surround the optic nerve, as well as increased sensitivity to toxins, conditions for toxicity optic nerve endings and transmission of infectious diseases.An increase in intraocular pressure becomes the most vulnerable point drive, resulting in glaucoma it is pressed and formed a pit.High intracranial pressure retains any fluid in space interconnect, resulting in nerve compression and swelling of the contained interstitial substance.
The CD also have a detrimental negative impact of hydrodynamic and hemodynamic changes that lead to a decrease in intraocular pressure.Any changes in the optic nerve always lead to dysfunction of the peripheral or central vision, while there may be a deterioration in the twilight of the differences of colors.Diseases related to the optic nerve degenerative wear, allergic or inflammatory in nature.Sometimes there are anomalies in the tumor and the development and structure of the optic nerve.
