Did you know? There are three types of tears. In this article, we will discover the three types of tears. But what is the purpose of the tears? Who has never cried in his life? Who has never shed tears? All we cry; Sometimes for one reason, sometimes for another.
Tears help to relieve psychic tensions. Crying is often a reflex action that relieves strong psychic tension, such as anxiety, fear, sadness, or any other overflow of even positive tension (“crying” with joy). Tears thus also have a psychic protective role. They are one of the means of nonverbal communication available to man, especially when he is a baby, child or elderly person or is unable to speak. So the purpose of the tears is some kind of call for help.
The tears of the emotion of an individual could thus contain a volatile chemical signal whose perception by another individual, through the receivers of the olfaction, would be at the origin of an effect on his state of mind (decreased sexual tension, testosterone in humans …).
*** The Purpose of the Tears
Tears thus have the role of psychic protector. They also have a role of non-verbal communication that men have, especially when they are babies, or children … or unable to express themselves clearly.
Emotional tears are hormone-related. There are hormones that affect the mood and make you sensitive to some really strong emotions. The latter seems to need to evacuate in the form of tears. The tears result from a mechanism of liberation during emotional tensions more or less important according to the people.
Let’s talk more specifically about nerve impulses. A strong emotion will trigger a message that will give order to the lachrymal glands to increase their tear fluid production. Tears flow on the face when the lachrymal passages fill up and saturate: it is thus this excess of liquid that comes out.
It is, therefore, our nervous system which is in charge of establishing a right balance with our emotional reactions. Weeping, we release the body of its tensions. One study has even shown that crying reduces sadness or anger by about 40%.
Crying thus avoids the infernal spiral of anxieties and permanent depression.
The tear fluid allows oxygenation and protection of the cornea.
*** Composition of Tears
Tears are water, of course, but not only! They also consist of tear fluid, secreted during tearing. It is produced from the filtration of blood but it also contains:
– mineral salts
– sodium chloride (NaCl)
– antiseptics (intended to destroy microbes)
– and lactotransferrins and lysozymes.
However, some components of this fluid (such as lysozyme) are not present in the blood and are synthesized directly by the main lacrimal gland located behind the upper edge of the orbit. A team from the University of Ohio (USA) analyzed the structure of the tear film: a thin layer of mucus, then a film of water covered with a fat envelope, called meibum. The superficial layer is secreted by the Meibomian glands located on the inner surface of the eyelid, this layer is mainly aqueous (consisting of water) but contains fatty substances. Among them, scientists have discovered a new family of lipids, including oleic amide.
Let start to discover the 3 types of tears.
1. The Reflex Tears
Reflex tears: Designed to remove harmful substances or particles, they are released in much larger amounts, and their aqueous layer contains more antibodies to stop microorganisms that might also try to enter. These are the ones that flow when peeling an onion.
Reflex tears are secreted during external aggression. They consist of water but not only, but they also contain:
– Lactotransferrins and lysozymes
– Other proteins
– sodium ions (Na +)
– chloride ions (Cl-)
– Other ions such as potassium ions (K +)
Some components of tears, such as lysozymes and lactotransferrins, are not present in the blood and are therefore synthesized directly by the main lacrimal gland during its secretion. Lactotransferrins and lysozymes are the most important proteins in tears. They are the most present in terms of quantity.
The ions Na + and Cl-, whose union creates the chemical formula of the salt (NaCl), are at the origin of the salinity of the tears. The salt concentration is about 78 g.L-1.
Other kinds of ions are also present such as K + potassium ions as well as electrically charged toxins.
It also contains glucose, urea, and proteins such as albumins or globulins.
The pH of the tears is about 7: they are therefore neutral.
2. The Basal Tears
There are basal tears, which permanently cover our eye and provide protection against external aggressions such as dirt, debris, and corneal damage. These tears, also called tear film, are therefore essential to protect our eyesight. Then we also produce what we call reflex tears.
*** Composition and the Purpose of the Basal Tears
The tear film is, as we said before, composed of three layers, themselves having different compositions:
– The lipid or superficial layer is composed of water but it mainly contains fatty substances.
– The lipid or surface layer is responsible for lubricating the surface of the tear film and preventing its evaporation too fast.
– The aqueous or intermediate layer contains, as its name suggests, a lot of water (98 to 99% approximately) it is also composed of different nutrients, oxygen and carbon dioxide. It also includes proteins, antibodies – released in basal tears – and a plasma filtrate made of lipocalins for transporting small hydrophobic molecules such as lipids. The proteins synthesized directly during secretion are lactotransferrins and lysozymes, which are antibacterials.
The aqueous or intermediate layer is the main component of the tear film; it cleans, evacuates foreign bodies and has the role of oxygenating the cornea.
The mucinic or internal layer is a thin viscous film containing mucins which are proteins used in the composition of many mucus, such as here the mucus of glycoproteins, that is to say, carbohydrates having, in addition, a protein complex.
The mucinic or internal layer has a function of surfactant, that is to say, that it allows the adhesion of the layers together through the mucins that moisten the cornea, which tends to repel water. The mucins also have the role of adhering the entire tear film to the cornea. They thus control the distribution of basal tears on the whole of this last.
*** Usefulness of Basal Tears
The tear film is responsible for feeding the conjunctiva and the cornea. It moisturizes, nourishes and lubricates the eye.
Its quantity rises to about 6 milliliters and is renewed by the blinking of the eyes approximately every 10 seconds.
When sleeping and the eyelid wink is zero, the lachrymal glands increase their secretions so that the fluid flows alone.
In parallel, the blood vessels of the cornea dilate to ensure oxygenation. Basal tears bring, as we said earlier, oxygen to the cornea in the absence of vascularization, but also other essential elements: glucose, amino acids, minerals…
Basal tears also play a vital role in the stability of vision and refraction, but this role has only recently been recognized by scientists.
3. Emotional Tears
Tears can also be caused by emotions. Indeed, certain events create tensions within our organization. The loss of a loved one, separation or disappointment reaches our morale and triggers the influx of hypothalamus. It is part of the autonomic nervous system and supervises hormonal secretions, the functioning of internal organs, and the triggering of reflexes. It is also the seat of emotions (also called the limbic system).
The creation of hypothalamus impulses releases stress hormones such as cortisone and creates epigastric tension: this is what you feel when you have “stomach or throat knotted. Sometimes the breathing becomes heavy by the nervous tension of the diaphragm and other muscles. The hypothalamus then triggers its role of regulator of tensions. The facial nerve VII (which has the role of connecting the parasympathetic fibers to different glands of the face) connected to the main lachrymal gland allows its stimulation by sending nerve messages.
Some people cry in silence, for a brief moment and in a discreet solitude. However, the only way to renew ourselves and drain our sadness, our frustrations and our tensions is through emotional tears.
Experts in psychobiology tell us that few behaviors make us as humane as laughter and crying. In fact, these two emotional expressions have many common aspects. They have, for example, a component of “perseveration”; in other words, when we laugh or weep, it is difficult for a fixed period of time to shorten. In addition, laughter and crying have the same goal: to make us feel better.
*** Composition and the Purpose of the Emotional Tears
Tears secreted during an emotion are richer in protein than those shed for external aggression. In addition to the composition of reflex tears, emotional tears contain hormones such as:
– and encephalic leucine.
The nerve messages causing the tears also lead to the production of natural analgesics.
*** Utilities of Emotional Tears
It is important that the accumulated tensions are released because a repressed emotion can have repercussions on the body. Tears can be used to relieve this stress, thanks to their analgesic that helps eliminate the toxins caused by the disorders and the emotion. Leucine and prolactin help relieve tension and soothe the crying individual.
Scientists even went so far as to calculate that crying reduces sadness or anger by about 40%.
Similarly, the sobs (uncontrollable spasms caused by crying) can loosen the multiple tensions accumulated in the body, such as epigastric tension: it is the phase of emotional discharge after which one generally feels relieved and relaxed.
The eye produces a briny liquid overflowing on the cheeks in the form of drops: tears. Its production is sometimes due to reflexes led by pain and irritation of the eye and other times by psychological and emotional situations.
Tears are essential to the proper functioning of the eye and also protect against all these new stimuli and foreign bodies present on Earth. So everyone is crying, so tears are really part of our daily lives.
The tears consist of tear fluid that is secreted by the lachrymal glands above the eyes, they are manufactured in greater or lesser quantities depending on different factors…