How eyeball.

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2019-02-17 14:00:27

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Eyeball, or organ of vision, despite its diminutive size, has a very complex anatomical structure. Macroscopically, this body has the form of a ball that is not quite perfect, because its visible front portion has a greater curvature than hidden from the eyes back surface. This fact determines inequality of dimensions of the eyes in different directions. Due to the convexity of the cornea in the anterior-posterior size of the organ of vision greatest. On average, a healthy adult he is close to 24 mm. Transverse and vertical axes are approximately the same: the average size of the transverse axis of the eye is 23.6 mm and 23.3 mm for the vertical.

Structure of the eyeball

In the body there are three important shell, which perform different from each other function.

  1. The Outer or fibrous sheath. In it there are two parts, which are completely different in anatomical relation. The largest portion of the sclera belongs to the sclera, or the tunica albuginea, and the rest – the cornea. The sclera is completely opaque, the fabric having a whitish hue. Thanks to its color, the eyeball, in particular its opaque part, called protein. In clinical practice as the sclera can determine different pathological conditions that occur in the eye and in the organism as a whole. So, redness of the eyeball may indicate acute inflammation in the organ of vision: conjunctivitis, keratitis, uveitis, etc. And yellowing of the tunica indirect evidence of liver disease-hepatitis. The eyeball, which presents also in front the cornea, it seems in this place painted in brown, green or blue color. However, this is not the cornea and translucent across her iris. The cornea is absolutely colorless and transparent, no blood vessels, only a bunch of nerve endings that allow it to be the most sensitive element in the body. If the eyeball to represent the percentage of parts of its fibrous sheath, the share of the cornea accounts for less than 16%.
  2. The Middle, or choroid. It is adjacent to the fibrous, but not in its entirety, but only in its scleral portion. Where the sclera passes into the cornea, vascular tract is separated from her and is at a distance from the cornea. In the middle shell there are three parts: the iris, ciliary (ciliary) body and choroidal. The iris serves as a diaphragm that regulates a light flux coming into the eye, to its photoreceptive structures. Controller function takes over the pupil, which can expand when the lack of light and narrow – in its excess. The ciliary body is necessary for continuous production of intraocular fluid necessary to nourish the eyes, keeping it tone. The choroid, or the choroid shell, represented by a network of blood vessels supplying the internal structures of the eye.
  3. Internal mesh or a shell. This is the most important part of the organ that responds to light and transmits visual information to brain cortical structures. Retina-a very thin and fragile tissue, in which, as a rule, there are two main areas: ciliary, which has highly differentiated cells, and optically active, in which these cells have. Their separation (dentate line) can be seen in the course of such research, as cycloscope when you examine the fundus.

The Eyeball in addition to the shells inside has the vitreous, which gives it a distinctive rounded shape and is involved in the refraction and the crystalline lens, which is involved in accomodating processes and refraction of light beams.


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Alin Trodden - author of the article, editor
"Hi, I'm Alin Trodden. I write texts, read books, and look for impressions. And I'm not bad at telling you about it. I am always happy to participate in interesting projects."

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