Life without It is only Silence

We use your eyes to perceive the things that speak with the wavelengths of light. We use ears to perceive other wavelengths called "sound," caused by vibration of molecules.

Wavelength of sounds that ear can perceive ranges between 20 and 20,000 Hertz. It can sense frequencies of sound that are above or below those limits. Indeed, it would be better to call this advantage rather than "inability." If it had not been created with this limited capacity, we would have been facing unbearable pain in our head. If an ear had been made to work with a wider range of hearing, we would have been disturbed with the footsteps of a little ant, the moaning of an insect laying eggs, the buzzing of beehives, and the sound of the fluttering birds. Therefore, the fact that it has sufficient sensitivity for us to meet our needs is an advantage.

Do not ever think that ear’s outer, visible pan is too simple. Its outer ear, which sometimes turns red when we are nervous, is placed in the best position according to the shape of our head so that it can receive sounds in a most efficient way. Because it is made up of elastic cartilage, its outer ear (A) is very flexible, and it won't break when we lie on it. The curves on it (known as the helix) and the hairs inside its channel are not made without a reason, either. Its cartilages have the perfect shape to channel sounds down towards its middle ear according to sound intensity and the direction it comes from. Because this special shape is formed according to the genetic code of a person, it is different in every person. The hairs in the canal serve to protect it from foreign objects like insects or dust. The canal that connects its outer part to a middle part is pretty wide, but if too much fatty wax accumulates here, it might experience temporary hearing loss.

The outer part is followed by the middle ear, which begins with the ear drum (tympanic membrane). Attached to this thin ear drum are three bones: the malleus, the incus, and the stapes, which are all placed in order. These little bones are jointed to each other at an angle of 105 degrees. With an action like a piston, they amplify even the smallest sound vibration coming from the ear drum and transmit it to the middle ear. Middle ear space is connected to our pharynx by a very thin canal called the Eustachian tube. In order to protect the ear drum from rupture, it is recommended that you open your mouth during an explosion or an intense sound. In that way, the sound waves that enter through our mouth will balance with the sound waves in ear’s canals so that the ear drum is protected.

The inner part, followed by ear’s middle part, is the most viral and sensitive area. Therefore, it is surrounded and protected by the bones of our skull. This inner part, which is an amazing piece of art and technology, comprises two wonderful receptor components. Those two little parts are placed in the same narrow area inside the temporal bone, but they perform different tasks. One of them is the cochlea, which is involved in hearing. The other part is the balance (vestibular) canals, consisting of semicircular canals, saccule and utricle. This balance organ enables you to stand straight and walk, run, or move without bumping or falling.

Like carved marble or forged metal, those parts are crafted out of bones that form a beautiful and intricate whole. Its cochlea is divided widthwise by a bony tube. The upper compartment above the tube is connected to an oval window, which is an outlet to the middle ear. The lower compartment below the tube is connected to a round window. Its inner part is a labyrinth of fluid-filled tubes. The fluid in the bony labyrinth, between the bone and membranes, is called perilymph, and the other fluid within the membranous structure is called endolymph.

Situated on the basilar membrane of its cochlea is a very small and special organ that is called the Corti’s organ. The organ of Corti contains the hearing cells (or hair cells), the receptors that are sensitive to sound waves, and other supporting cells. Because the length of the cells in the organ of Corti varies, different parts of ear’s cochlea are sensitive to sounds of different wavelengths.

The sound waves travel via the malleus, incus and the stapes and through its oval window, agitating the perilymph of cochlea. After that, the sound waves cause Reissner's membrane in cochlea to vibrate, which then results in wave movement in endolymph. The wave movement continues along this membrane until it reaches Corti’s organ. Special receptor cells (or hair cells) of Corti’s organ are the ultimate vibration receptors. Their surfaces consist of very small strands (cilia). Those little strands bend and twist when sound waves are received. Right at this point, a very important event occurs: it is movement of these strands which converts mechanical energy (that is produced by vibrations of sound waves) into electrical impulses. Those electrical impulses are then sent to our brain via the auditory nerve (nervus cochlearis) of the brain, where they are perceived as "sound." The same sound waves continue their way to the perilymph and pass into the round window, section between the middle ear and inner ear. The round window pushes out to dissipate sound vibrations in the perilymph and thus lessens their pressure.

Speed of hearing depends on speed of the sound that travels through membrane and little bones. However, once sound waves begin to pass to our brain as an electrical impulse along the auditory nerve, the hearing process increases its speed. Then our brain immediately interprets and reacts to the sound waves. We are not aware of all these rapid activities which are done perfectly in fractions of a second. We only say that we can hear something ordinarily.

Maintaining our balance

Have you ever seen an acrobat walking on a rope or a mountain climber in action? Or its better to give a better example that might be more familiar to you? Remember what you do on your bicycle to keep from falling off. At the slightest mistake, the acrobat might topple from the rope, the climber might slip off the cliff face, and you might fall off your bicycle. While you are making unconscious (reflex) movements to keep your balance, have you ever thought about what busy operations are going on in the ear’s system? It has been equipped with very sensitive receptors which help you stay stable during your continual, different movements. Those receptors immediately recognize the changes occurring as a result of your slightest motion; they warn your body to adjust to your new position by sending out information to the spinal cord and to brain about the new situation.

How do you feel the sensation of balance and how do you react with the right reflex action? To find an answer to that, you need to re-examine ear’s anatomical structures mentioned before. At the base of its semi­circular canals there is a bulb-like enlargement which opens to the saccule and the utricle. Three semicircular canals are situated at 90-degree angles to each other in three-dimensional space.

Semicircular canals contain few sensory hair cells but there are plenty of them in the bulb-like enlargement. The strands of these cells, placed delicately, have enough elasticity to twist and bend during movement. The receptors for balance in saccule and utricle are covered with a thin membrane containing gelatinous layer and tiny calcite crystals (cupula terminalis). Depending on its density, the endolymph fluid in semicircular canals moves against the direction that your head and body move in. Similar to the uncontrolled movement of passengers in an accelerating or moving vehicle, depending on speed and direction, movement and speed of endolymph differs from general movement of your body. For example, when a car turns right, passengers move to the left with turning acceleration, and when a fast-moving car brakes suddenly, the passengers are thrown forward. Similarly, depending on its acceleration and momentum, every change in your movement causes fluid in semicircular canals to move. Triggered by movement of endolymph fluid, gelatinous mass with the calcite pieces is displaced, causing strands of the receptors to twist. Every movement of your head warns cells of different parts, and via the vestibular nerve (nervus vestibularis) the nervous system is notified of changes occurring in your balance.

Thankfulness and contemplation

Serious ear illnesses include middle ear infection (otitis media), which is frequently seen in children; otosclerosis, which is the limited ability of stapes to transmit sound waves because its base becomes fixed to the oval window; and several hearing disorders which might be present at birth or occur later in life, depending on the level of damage to the auditory nerve. Witnessing the effects of those illnesses, you would understand how important it is to be able to hear and stand straight and balanced.

Practise two-way consecutive translation of the text:

nature's building blocks

будівельні цеглинки природи

What are atoms? Over two thousand years ago, about 400 В. C., the Greek philosopher Democritus tried to figure out what the world is made up of and how it came to be the way it is. He came to the conclusion that all things are made up of tiny particles, too small to be seen. There are many kinds, he thought, and they are always moving about, sometimes combining, and sometimes separating again. Democritus deserves tremendous credit for giving us this theory. The discoveries of science in over two thousand years of work and study show that Democritus was right. Investigations by chemists have shown that every chemical compound, such as salt or water, is made up of many tiny particles called molecules. In solids and liquids they are packed closely together. In gases they are spread out thin, with big spaces separating the molecules from each other. Each molecule in a compound is the same as all the other molecules in the same compound, but it is different from the molecules in other compounds. Since there are thousands of different compounds, there are thousands of different kinds of molecules, ranging from simple ones, like the molecules of salt or water, to very complicated ones found only in living things. Further study has shown that the molecules themselves are made up of still smaller particles known as atoms. Although there are thousands of different molecules, there are only 103 different kinds of atoms. These 103 different atoms, known as the chemical elements are the building blocks out of which all material things are made.

Що таке атоми? Більш ніж дві тисячі років тому, близько 400 р. до н.е., грецький філософ Демокріт спробував розгадати, з чого створено все-світ і чому він саме такий. Він дійшов висновку, ідо всі предме-ти утворені з частинок, надто малих, щоб їх можна було бачи-ти. їх багато видів, при пустив він, і вони весь час рухаються, то сполучаючись, то роз'єднуючись знову. Демокріт заслуговує на вели-чезну пошану за те, що він дав нам цю теорію. Наукові відкриття, зроблені протягом більш ніж двох наступних тисячоліть напруженої дослідницької роботи доводять, що Демокріт був правий. Дослідження в галузі хімії показали, що кожна хімічна сполука, наприклад сіль або вода, складається з багатьох найдрібніших частинок, що називаються молекулами. У твердих тілах і рідинах вони щільно розміщені. У газах вони розміщені вільніше, з великими проміжками, що відокремлюють молекули одну від одної. Кожна молекула сполуки така само, як і всі інші молекули у цій сполуці, але відрізняється від молекул в інших сполуках. Оскільки є тисячі різних сполук, є й тисячі різних видів молекул – від прос-тих, таких як молекули солі й води, до дуже складних, виявле-них тільки в живих істотах. Подальші дослідження показа-ли, що самі молекули складають-ся з ще менших частинок, відомих як атоми. Хоча існують тисячі різних молекул, є лише 103 різних види атомів. Ці 103 різних атоми, відомі як хімічні елементи, є будівельними цег-линками, з яких складається весь матеріальний світ.