What is the eye? What functions does the eye in the human body do?

The ability to perceive information about the world through vision is the most amazing and useful ability of a person. We capture the picture of what is happening, like a photo. The eye is that "optical device" that allows us to see the world around us and send information about it.

The eye is the organ of human sight

According to psychologists, from 70 to 80% of the information we perceive visually. The optical system of the eye, like a camera, has special mechanisms for capturing light reflected from the object, and processing the information obtained. So what is the eye and how is our organ of vision organized?

In the human skull the organ of vision is located in the eye sockets. These cavities are formed at once by several bones, among which the upper jaw, wedge-shaped, latticed, zygomatic, frontal. The glaznica is a pyramid, the top of which is turned into the cranial cavity, and here there are a visual canal and a visual gap through which the nerves and vessels with the organ of vision communicate.

What is the eye? It is a globular organ with a diameter of about 24-25 mm, which is filled with liquid inside and consists of three membranes. Movement of the eyeball due to the work of six muscles: the upper, lower, inner, outer, upper oblique and lower oblique. The auxiliary apparatus also includes eyelids, eyelashes, eyebrows. Do not forget about the lacrimal gland, the secret of which washes and thus moisturizes the surface of the eye.

Structure of the eyeball

What is the eye in terms of biology? It is the organ of vision, which is filled with a transparent liquid. The eye is covered by three shells: a sclera, a vascular membrane and a retina. Functions largely determine the structure of the eye, the photo of which is shown below.

Sclera is the thickest shell of the eye. It performs a protective function, and also in the front part forms a cornea that enters the optical apparatus of the organ of vision. At the border of the cornea and actually the sclera is the limb zone.

The vascular membrane is permeated with numerous vessels, the task of which is to feed the entire organ. This shell forms a ciliary, or ciliary, body (muscle), which is responsible for changing the curvature of the lens, i.e. For accommodation. Also, the derivative of the choroid is the iris, which has a hole in the middle - the pupil. The color of the iris determines in many ways the color of the eyes themselves: they will be brown, green, gray or blue.

The retina is the innermost layer of the eye. Here are located visual pigments in the composition of rods and cones, which are responsible for the perception of the picture. Actually, on the retina, an initially inverted image is formed, the information about which is then transferred to the occipital zone of the cerebral cortex.

The iris divides the area between the cornea and the lens into two chambers: anterior and posterior, which are filled with watery moisture. The functions of this fluid are the feeding of the lens and the cornea, as well as in the refraction of the light beam.

Basic visual pigments

The optical system of the eye allows you to perceive a color image during the day and black and white at night. For the first, such structures as cones are responsible. Most of all, their concentration is in the area of the yellow body, where the overwhelming majority of the light is focused.

In the cones are the following pigments:

1. Erythrab - is responsible for the perception of shades of red and yellow.

2. Chlorolab - responsible for the perception of the green spectrum of light.

3. Yodopsin - responsible for the perception of cold blue and violet shades.

In the dark, cones cease to function, and instead of them, sticks are included in the work. These structures form a black and white image, and the pigment, which is responsible for this, is called rhodopsin. It is proved that people with impaired vision are better seen in the dark.

What is the eye like an optical system?

In order for the image to appear, a beam of light reflected from the object must reach the retina of the eye. This beam is refracted and focused with the aid of a complex optical apparatus of the eye. What are its structures?

The cornea has the highest degree of refraction. It is also the first structure in the path of a beam of light. Further, it passes through the pupil and is slightly refracted because of the transition to a liquid medium, because In the chambers of the eye is watery moisture. Then the light is refracted once more, when it comes to the lens of the eye.

Normally, a beam of light must reach the yellow body on the retina of the eye. If he focuses, not reaching the retina, there is a disease - myopia. If light falls on the area behind the retina, then hyperopia occurs. That's what the eye is, and what functions this organ of vision performs.