One of the most important human organs is the eyes. Thanks to them, we receive information about the outside world. The structure of the eyeball is quite complex. This body has its own characteristics. About which ones, we will talk further. We will also dwell in more detail on the structure of the eye as a whole and one of its components - the cornea - in particular. Let's discuss the role of the cornea in the work of the organ of vision and whether there is a relationship between its structure and the functions performed by this element of the eye.
The human organ of vision
A person with the help of the eyes has the ability to receive a large amount of information. Those who, for whatever reason, have lost their sight, have a very hard time. Life loses colors, a person can no longer contemplate the beautiful.
Furthermore, daily activities also become difficult. A person becomes limited, he cannot fully live. Therefore, people who have lost their sight are assigned a disability group.
Functions of the eye
The eye performs the following functions:
- Distinguishing the brightness and color of objects, their shape and size.
- Monitoring the movement of objects.
- Determining the distance to objects.
SoThus, the eyes, along with other organs of a person, help him live a full life, without feeling the need for outside help. If sight is lost, the person becomes helpless.
The eye apparatus is an optical system that helps a person perceive the world around him, process information with high accuracy, and also transmit it. A similar goal is fulfilled by all the constituent parts of the eye, the work of which is coordinated and coordinated.
Light rays are reflected from objects, after which they touch the cornea of the eye, which is an optical lens. As a result of this, the rays are collected at one point. After all, the main functions of the cornea are refractive and protective.
Then light travels through the iris to the pupil of the eye and on to the retina. The result is a finished picture in an inverted position.
The structure of the eye
The human eye has four parts:
- Peripheral, or perceiving part, which includes the eyeball, eye apparatus.
- Conducting paths.
- Subcortical centers.
- Higher visual centers.
The oculomotor muscles are divided into oblique and rectus muscles of the eye, in addition, there is also a circular one and one that raises the eyelid. The functions of the oculomotor muscles are obvious:
- Rotating eyes.
- Raising and lowering the upper eyelid.
- Closing the eyelids.
If all the eye apparatuses work correctly, then the eye functions normally - it is protected from damage and harmfulenvironmental impact. This helps a person to visually perceive reality and live a full life.
Eyeball
The eyeball is a spherical body located in the eye socket. The eye sockets are located on the front surface of the skeleton, their main function is to protect the eyeball from external influences.
The eyeball has three shells: outer, middle and inner.
The first is also called fibrous. Has two departments:
- The cornea is a transparent anterior section. The functions of the cornea of the eye are extremely important.
- Sclera is an opaque back section.
The sclera and cornea are elastic, thanks to them the eye has a certain shape.
The sclera is about 1.1 mm thick and is covered by a thin, transparent mucous membrane called the conjunctiva.
Cornea of the eye
The cornea is called the transparent part of the outer shell. The limbus is where the iris meets the sclera. The thickness of the cornea corresponds to 0.9 mm. The cornea is transparent, its structure is unique. This is explained by the arrangement of cells in a strict optical order, and there are no blood vessels in the cornea.
The shape of the cornea resembles a convex-concave lens. It is often compared to glass for watches that have an opaque frame. The sensitivity of the cornea of the eye is due to the large number of nerve endings. It has the ability to transmit and refract light rays. Its refractive power is enormous.
When a child turnsten years, the parameters of the cornea are equal to the parameters of an adult. These include shape, size and optical power. But when a person becomes elderly, an opaque arc forms on the cornea, which is called senile. The reason for this is s alts and lipids.
What is the function of the cornea? More on that later.
The structure of the cornea and its functions
The cornea has five layers, each with its own functionality. The layers are as follows:
- stroma;
- epithelium, which is divided into anterior and posterior;
- Bowman's membrane;
- Descemet's membrane;
- endothelium.
Next, consider the correspondence between the structure and function of the cornea.
The stroma layer is the thickest. It is filled with the thinnest plates, the fibers of which are collagen. The arrangement of the plates is parallel to the cornea and to each other, but the direction of the fibers in each plate is different. Due to this, the strong cornea of the eye performs the function of protecting the eye from damage. If you try to pierce the cornea with a scalpel that is poorly sharpened, then it will be quite difficult to do this.
The epithelial layer has the ability to self-heal. Its cells regenerate, and even a scar does not remain at the site of damage. Moreover, the recovery is very fast - in one day. The anterior and posterior epithelium is responsible for the fluid content in the stroma. If the integrity of the anterior and posterior epithelium is broken, then the cornea may lose its transparency due tohydration.
The stroma has a special layer - Bowman's membrane, which has no cells, and if it is damaged, scars will definitely remain.
Descemet's membrane is located next to the endothelium. Also composed of collagen fibers, prevents the spread of pathogenic microorganisms.
Endothelium is a single cell layer that nourishes and supports the cornea, does not allow it to swell. It is not a regenerating layer. The older the person, the thinner the endothelial layer.
The trigeminal nerve provides innervation to the cornea. Vascular network, nerves, anterior chamber moisture, tear film - all this provides its nutrition.
Functions of the human cornea
- The cornea is strong and highly sensitive, so it performs a protective function - it protects the eyes from damage.
- The cornea is transparent and has a convex-concave shape, so it conducts and refracts light.
- Epithelium is a protective layer, thanks to which the cornea performs a function similar to a protective one - it prevents infection from getting inside. Such a nuisance can only occur with mechanical damage. But even after that, the anterior epithelium will quickly recover (within 24 hours).
Harmful factors affecting the cornea
Eyes are regularly exposed to the following harmful effects:
- contact with mechanical particles that are suspended in the air;
- chemicals;
- air movement;
- temperature fluctuations.
When foreign particles enter the human eye, the unconditioned reflex closes the eyelids, tears flow intensely, and a reaction to light is observed. Tears help flush out foreign agents from the surface of the eye. As a result, the protective functions of the cornea are fully manifested. There is no serious damage to the shell.
The same protective reaction is observed with chemical exposure, with strong wind, bright sun, cold and heat.
Diseases of the organs of vision
There are a lot of eye diseases. We list some of them:
- Presbyopia is an senile form of farsightedness in which the elasticity of the lens is lost and the ligaments of zirconia that hold it in place weaken. A person can see clearly only objects that are at a far distance. This deviation from the norm appears with age.
- Astigmatism is a disease in which light rays are refracted unevenly in different directions.
- Myopia (myopia) - the rays intersect in front of the retina.
- Far-sightedness (hypermetropia) - the rays intersect behind the retina.
- Protanopia, or color blindness - with this disease, a person is almost unable to see all shades of red.
- Deuteranopia - green color and all its shades are not perceived. The anomaly is congenital.
- Tritanopia - with this refractive error of the eye, a person is unable to see all shades of blue.
If any disturbances occur in the functioning of the organs of vision, it is necessary to contact a specialist - an ophthalmologist. The doctor will conduct all the necessary tests and, based on the results, make a diagnosis. Then you can start treatment. As a rule, most diseases associated with disruption of the eyeball can be corrected. The only exceptions are congenital anomalies.
Science does not stand still, so now the function of the human cornea can be restored by surgery. The operation is quick and painless, but thanks to this, you can get rid of the forced need to wear glasses.
