The sensory organs contribute to the knowledge of the diversity of the surrounding world . Eyes provide us with ninety percent of all incoming information. The human organs of vision are so closely connected with the brain that they are entrusted with the main function of the connection of the nervous system with the outside world. The material for the photosensitive membrane of the eye is the brain nerve tissue. Human organs of vision use the peripheral part of the image analyzer - photoreceptors. The visual analyzer uses the optic nerve as a conductor . This whole complex mechanism works on the central part, which is concentrated in the visual zone, in the occipital lobe of the cerebral cortex.
Speaking of the organs of vision, we often imagine those elements that are outside. First of all, it is a pair of eyeballs (eyes) and organs that perform auxiliary functions. These include the eyelids, eyebrows, eyelashes, lacrimal glands and eye muscles. The eyelids are skin folds, they limit the palpebral fissure and close it if necessary. On the inner surface of the eyelid is the mucous membrane, which ophthalmologists call the conjunctiva. The main function of the eyelid is to lubricate the surface of the eye with tear fluid, as well as protect this surface from drying out and mechanical influences. In a normal state, a person blinks every five seconds.
The pride of any beauty - eyelashes - are on the edges of the eyelids, they are located in 2-3 rows, their number reaches eighty. They perform a protective function, preventing foreign particles from entering the mucous membrane of the eye. A huge role in ensuring the normal functioning of the eye is played by the lacrimal gland. She is located outside in the upper corner of her eye. She constantly and continuously develops a special secret - a tear. The daily volume reaches 100 ml. A tear through the nasolacrimal canal constantly drains into the nasal cavity. Chemically, a tear is a 1.5 percent solution of ordinary table salt (NaCl), which contains a bactericidal substance (lysozyme). A tear performs several functions. The task of removing the substance, the product of nervous tension and emotional stress is added to washing the surface of the eyeball, moisturizing it and protecting it from bacteria and foreign particles.
The human organs of vision are in constant motion. The eye muscles are responsible for the movement of the eyeballs. The arsenal of the human eye has four straight and a pair of oblique muscles. Their synchronous operation ensures the installation of the visual axes of each eye, so that they converge on the subject being examined.
The eyeball is a spherical natural lens, the diameter of which reaches two and a half centimeters. It is limited to three shells. The outer one is called fibrous (protein), the middle one is called vascular, and the inner one is called photosensitive (retina).
The human organs of vision are a complex natural mechanism, which requires proper care for normal functioning. Just like the human circulatory system, the eyes do their job with the only difference being that they take a little rest during the person’s sleep, but their functioning does not stop, but only goes into a more “economical mode”.
For normal eye function, visual hygiene practices must be strictly adhered to. This includes the division of working time into workloads and periods of short-term breaks. A set of exercises has been developed that allows not only to train and tone the muscles of the eyes, but also to stabilize the lens and the course of nervous processes.
Caring for your own vision will guarantee that you can enjoy the variety of colors of the world around us for a long time.