More than 80% of all information man gets eyes (visually). We distinguish color, shape, distance to items, movement of various objects. However, we do not think about the fact that the eyes are the most complicated body of perception and information transfer. Let's understand how it works.
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Eyes structure
Human eye has a spherical shape, hence his name Eye Apple. It consists of three shells: outer, vascular and retina, as well as internal content.
Front of the outer shell cornea Like a transparent window into the outside world, through it the rays of light fall inside the eye. Having a convex form, it not only misses, but also refracts these rays. The rest of the outer shell sclera opaque and externally similar to boiled egg whites.
Second shell vascular consists of a plurality of small vessels by which the blood supplies the eye with oxygen and nutrients. In this shell also allocate several parts: front - Rainbow, Middle - ciliary body and rear - Horioidey. The color of our eyes is determined by the pigment content in the iris, which is visible through the cornea. In the center of the iris is a round hole pupil. Its dimensions change depending on the illumination: it increases in the dark, in bright light decreases.
Space between the cornea and iris call Front camera. Ciliary body It produces intraocular fluid, which circulates inside the eye, washing and feeding the cornea, crystal, vitreous body. This liquid flows through a special drainage system in the angle of the anterior chamber. In the thicker of the ciliary body there is an accommodation muscle, which adjusts the form of lens using ligaments.
Horioide the back of the vascular shell directly contacts the retina, providing it with the necessary food.
Third shell eye Mesh (or retina) consists of several layers of nerve cells and lins it from the inside. It is she who provides us with vision. On the retina display the items that we see. Information about them is then transmitted by visual nerve in the brain. However, not the whole retina sees the same: the greatest visual ability possesses the central part of the retina, where the main amount of visual cells is located (colums).
Inside the shells are concluded Front and rear (Between the iris and crystal) Cameras, filled with intraocular liquid, and most importantly Crystalik and Vitreous body. Crystal has the shape of a double lens. Like a cornea, it misses and refracts the rays of light, focusing the image on the retina. The vitreous body has a gauge consistency and separates the crystal from the eye bottom.
The coordinated job of all departments of the eye allows us to see in the distance and near, day and at dusk, perceive the variety of colors, orient in space.
