Anatomy of the eye
Eye can be called a complicated optical device. Its main objective is “to convey” the right image the optic nerve.
The structure of the eyes suggests the presence of different structures.
The cornea is the transparent skin covering the front of the eye. There are no blood vessels, it has great refracting force. The cornea is bordered by an opaque outer shell of the eye ? sclera. The anterior chamber of the eye is the space between the cornea and iris. It is filled with intraocular fluid. Iris – the shape looks like a circle with a hole inside (pupil). The iris is composed of muscle contraction and relaxation in which the pupil size changes. It is included in the choroid. The iris is responsible for eye color (if he is gay – so there are little pigment cells when brown – a lot). The iris performs the same function as the aperture of the camera, adjusting the light flux. Pupil – the hole in the iris. Its size is usually dependent on the level of illumination. The lighter, the smaller pupil is. Crystalline lens is natural lens’ eyes. It is transparent, elastic – can change its shape, almost instantaneously, “bridging the focus”, due to what one sees is good and near and far. The crystalline lens as the cornea is included in the optical system of the eye. Retin-A – consists of photoreceptors (they are sensitive to light) and nerve cells. Cell receptors located in the retina, are divided into two types: cones and rods. In these cells, which produce the enzyme rhodopsin converts light energy (photons) into electrical energy of nerve tissue ? is the photochemical reaction. Sticks have high sensitivity and allow us to see in low light, and they are responsible for peripheral vision. Cones, on the contrary, demand for its work more light, but they can see fine details (responsible for central vision), make it possible to distinguish colors. Sclera – non-transparent outer shell of the eyeball, passing in front of the eyeball into the transparent cornea. It is a small number of nerve endings and blood vessels. Choroid - lines the back part of the sclera, retina adjacent to it, with which it is closely related. Choroid is responsible for the blood supply to the intraocular structures. In diseases of the retina are often involved in the pathological process. Optic nerve – with the help of the optic nerve signals transmitted from nerve endings in the brain.
Thus a person sees through the eye, where information is transmitted through the optic nerve, chiasma, optic tract in certain areas of the occipital lobes of the cerebral cortex, where a is the picture of the outside world that we see. All these bodies make up our visual analyzer or visual system. The presence of two eyes allows us to make our vision stereoscopy (to form three-dimensional image). The right side of the retina of each eye passes through the optic nerve, “right side” of the image on the right side of the brain, similar acts left side of the retina. Then the two images – left and right – brain connects together.