The 11 Parts of the Eye and Their Functions

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Parts of the Eye and Their Functions

The vision stands out among human sensoperceptive systems because of its high complexity reason you must know the 11 Parts of the Eye and Their Functions. The structure of the eye, the main organ of sight, is a good example of this, to the point that it has come to be used as a supposedly irrefutable argument by those who defend that life was created and designed by a god.

The analysis of the parts of the eye can be extended to a large extent since the organs of vision are composed of many structures. In this article, we will focus on the main ones and the general description of the transduction process that makes light energy come to be perceived as images.

What is the eye?

The eyes are the basis of the visual system. These organs transform light energy into electrical impulses that, when transmitted to the visual cortex of the occipital lobe, allow the three-dimensional perception of shape, movement, color, and depth.

The eyeballs have a spherical shape and an approximate diameter of 2.5 cm. They are divided into two sections: the anterior and posterior chamber filled respectively with aqueous and vitreous humor, fluids that regulate intraocular pressure. The anterior chamber is smaller and is located between the cornea and the iris, while the posterior chamber is made up of the rest of the parts of the eye.

Unlike what happens with other sensory organs, the eye is partially derived from the central nervous system. Specifically, the retina, which receives the light information, develops from the diencephalon, the embryonic structure that also gives rise to the cerebral hemispheres, the thalamus, and the hypothalamus.

In the retina, we find two types of photoreceptors, the rods, and the cones. While the cones allow daytime vision and the perception of color and details, the canes are adapted for night vision and produce low-resolution images in black and white.

Parts of the Eye and Their Functions

The eyes work similarly to photo cameras. The lens is adjusted according to the distance of the stimulus, serving as a kind of lens that allows the refraction of light; The pupil is the diaphragm through which the image enters the eye and projects into the retina, from where it will be sent to the brain through the optic nerve.

Here are the 11 Parts of the Eye and Their Functions, kindly read through carefully:

1. Cornea

The cornea constitutes the anterior part of the eye and is in contact with the outside. It is a transparent structure that covers the iris and the lens and allows light refraction. Tears and aqueous humor allow the cornea to function properly since they perform functions equivalent to those of the blood.

2. Iris

This structure separates the anterior and posterior chambers from the eye. The iris dilator muscle increases the size of the pupil (mydriasis), and the sphincter muscle reduces it (myosis). The iris tissue is pigmented because of the presence of melanin; This results in the color of the eye, by which we can easily identify this structure.

3. Pupil

There is a circular hole in the center of the iris that allows regulating the amount of light that enters the eye when changing size as a result of mydriasis and myosis; This opening is the pupil, the dark part that is located in the center of the iris.

4. Crystalline

The lens is the “lens” that is located behind the iris and allows visual focus. Accommodation is the process by which the curvature and thickness of the lens are modified to focus on objects based on their distance. When the light rays pass through the lens, the image is formed in the retina.

5. Aqueous humor

The aqueous humor is found in the anterior chamber of the eyeball, between the cornea and the lens. It nourishes these two structures and allows the eye pressure to remain constant. This liquid is composed of water, glucose, vitamin C, proteins, and lactic acid.

6. Sclerotic

The sclera covers the eyeball, giving it its characteristic white color and protecting the internal structures. The anterior part of the sclera is attached to the cornea, while the posterior part has an opening that allows the connection between the optic nerve and the retina.

7. Conjunctiva

This membrane covers the sclera. It contributes to the lubrication and disinfection of the eyeball since it produces tears and mucus, although the tear glands are more relevant in this regard.

8. Choroid

We call “choroid” the layer of blood vessels and connective tissue that separates the retina and the sclera. The choroid provides the retina with the nutrients and oxygen it needs to function properly, in addition to maintaining a constant temperature in the eye.

9. Vitreous humor

The posterior chamber of the eye, which is located between the lens and the retina, is full of the vitreous humor, a jelly-like liquid with a density greater than that of the aqueous humor of the anterior chamber. It constitutes the major part of the eyeball, and its functions are to provide it with stiffness, dampen impacts, maintain intraocular pressure, and fix the retina.

10. Retina

The retina is the true receiving organ of the visual system since, in this structure, the rods and the cones, the photoreceptor cells, are located. This membrane covers the back of the eye and has a function similar to that of a screen: the lens projects the images perceived in the retina, from where it will be transmitted to the brain through the optic nerve.

Specifically, the light rays are received by the area of ​​the retina known as the fovea, which is very rich in cones has a great visual acuity and therefore is the main responsible for detailed vision.

11. Optic nerve

The optic nerve is the second of the twelve cranial nerves. It is a set of fibers that transmit the light impulses of the retina to the cerebral optic chiasma. From this point, the visual information is sent to other areas of the brain in the form of electrical signals.

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