Traditional myths suggest that people cry when they are sad, while feeling lonely, after fighting with their loved ones, in frustration, after a death of loved ones, in a marriage ceremony, when girls leave her husband, or sometimes when we are extremely happy. But tears tend to flow out of eyes and we are unable to control them.
Every person cry, but did you ever thought why? In addition, you’ll be surprised to know that there are different types of tears. Let’s dive into reasons and types of tears.
Biologically, crying is inhibited by a hormone called testosterone in men in prolactin in women. Men have more Testosterone while women have more prolactin which stimulates tears. Apart, from these two hormones, other hormones and neurotransmitters also contributes in crying. Serotonin (5-hydroxytryptamine, 5-HT) is a neurotransmitter or a chemical found in the human body which carries signals along and between nerves is induces by the emotion of love and make tears fall from eyes. While ACTH (adrenocorticotropic hormone) activates in stress and contributes to crying.
There are four types of tears:-
Continuous or basil tears: It has three levels — a nutrient-rich mucus that sticks to the eyeball, a watery in-between layer and a thin veneer of antioxidant vitamin, mineral and essential-fatty-acid-rich oil. These tears are constantly secreted by the lacrimal gland present in the outer edge of the eyeball and is released whenever we blink our eyes. It basically protects our eyes by lubricating it every time we blink.
Reflex Tears: These are also protective tears which protect our eyes from chemicals. When fast blowing winds strike our eyes like at the time of riding a bike or when smoke creates itching in our eyes, reflex tears are secreted in limited amount to protect eyes. Another example is while chopping onion our eyes get automatically lubricated and tears start flowing from eyes.
Induced tears: an allergically or chemically mediated response and
Psychogenic tears or tears of emotion: Only humans have this type of tears and it comes depending on emotions like frustration, sad, stress, happy, etc. In addition, these tears come out in large quantity that too with a continuous flow and are most easily observed.
According to experts, only humans are gifted with the Psychogenic tears and these tears don’t come out when we are upset (or any other emotion) but they help in overcoming the feeling of disappointment. Also, only humans have tears of emotion while other species like animals cry by making peculiar sound without any tears. Similar case is with new born babies, they cry without tears.