Factory of tears
Two tear glands are located at the top of the outer corner of each eye (under the eyelid) quite side by side with each other. In them, actually, the water component of tears is produced (this is about 98%). By special canals, tears come into the thick of the conjunctiva, where they are "enriched" with mucus and fat, also appearing in the composition of bitter droplets. Standing out of the lacrimal papillae, the "salt water" is evenly distributed over the eye surface with each blink. Excesses of it and tears that have fulfilled their functions (namely, purification) flow into the tear ducts in the inner corner of the eye, which, incidentally, are associated with the nasal cavity. That's why, when we cry, it also flows from the nose. Usually tear glands of one eye produce from 0.5 to 1 ml of fluid per day. However, violations of the mental state of a person and some diseases will help to change these indicators. So, a pea of tears consists of three layers: mucinous (mucous), liquid and lipid (fat). The lower mucosal layer is the "foundation" for the entire film (mucins are an important link between the epithelium and the liquid). In water - microelements (sodium, calcium, ions of chlorine, etc.) are dissolved, giving a tear a salty taste, as well as many other valuable substances (albumin, lysozyme, immunoglobulin A), which provide antimicrobial properties. The upper - the thinnest layer of fat - slows the evaporation of the liquid. By the way, the chemical composition of tears is similar to the composition of blood, and they carry information as much. By the "formula" of tears you can "learn" the age and psychological state of a person, and even diagnose many ailments. For example, the Australian oculists determine thus oncological diseases - in the tears of people suffering from this disease, a special "cancer" protein is found.
Living Water
To the eye was keen, it should be regularly moisturized. In addition to "irrigation," drops of joy or despair guarantee the full nutrition of the cornea and oxygen saturation, the reflection of microbial "attacks", the washing out of "waste" products of vital activity and various sorines. All this is possible only if the liquid is evenly distributed over the surface of the eye thanks to the movement of the eyelids, reminiscent of the movement of the car wipers. During crying, a short energetic breath and a long exhalation alternate (training of the circulatory and respiratory systems), then the breathing stabilizes - and a pleasant relaxation (as after physical exertion) is guaranteed. In addition, the secret of tears contains psychotropic substances that reduce feelings of tension and anxiety (through the tears the body part with the excess of hormones that stand out in stressful situations "volley"). According to American scientists, the composition of tears depends on the reason for their shedding. The densest, the most saturated, the salty are grief and despair. They found a lot of protein and special chemical elements formed during stress. It is very harmful to save such "good". The suppressed negative can result in disorders of the nervous system, cardiovascular diseases, ulcer and even cancer. It is no accident that men who "do not cry" live on average seven years less. So cry for health! According to statistics, 74% of women and 20% of men cry without tears, respectively, 36% and 25%, 36% and 25% respectively, 41% and 22% of love and related experiences. 71% of ladies and 40% of macho tend to sob over the work of art. The biggest crypts in the world, according to the Dutch professors, Chileans (in second place - American women, on the third - Turkish women). Ukrainian women in the ranking for some reason no ... Although the crying of our Yaroslavna and without that there are legends. Tears caused by physical pain are analgesics. They contain bioactive substances that act like morphine. In addition, it is a powerful antibacterial and antiviral shield - tears revealed an enzyme lysozyme, which kills 95% of bacteria in 5-10 minutes. Therefore, in the ancient custom to wash the wounds of soldiers, tears were a rational grain.
Why do not they cry?
On average, a person sheds about 70 liters of tears for life. It is believed that the weaker sex is more tearful because of the prolactin hormone contained in the blood, responsible both for the ability to start a tear, and for the production of milk during breastfeeding. In men, its level is low, but the amount of testosterone, which prevents the accumulation of tear fluid, is high.